From 73cf07e9a4f1000087118c24ef5d56f621f41160 Mon Sep 17 00:00:00 2001
From: Sebastien Deleuze <sdeleuze@pivotal.io>
Date: Thu, 17 Aug 2017 14:30:14 +0200
Subject: [PATCH] Fix overridden methods nullability

Issue: SPR-15869
---
 .../org/springframework/aop/TargetSource.java |  1 +
 .../AspectJAdviceParameterNameDiscoverer.java |  2 ++
 .../aspectj/SimpleAspectInstanceFactory.java  |  2 ++
 .../SingletonAspectInstanceFactory.java       |  2 ++
 .../AbstractAspectJAdvisorFactory.java        |  2 ++
 .../BeanFactoryAspectInstanceFactory.java     |  2 ++
 ...ngletonAspectInstanceFactoryDecorator.java |  2 ++
 .../ReflectiveAspectJAdvisorFactory.java      |  2 ++
 .../config/AdvisorComponentDefinition.java    |  1 +
 .../AspectJAutoProxyBeanDefinitionParser.java |  2 ++
 .../config/ConfigBeanDefinitionParser.java    |  1 +
 .../aop/config/MethodLocatingFactoryBean.java |  1 +
 .../config/PointcutComponentDefinition.java   |  2 ++
 ...BeanFactoryAwareAspectInstanceFactory.java |  1 +
 .../AbstractSingletonProxyFactoryBean.java    |  1 +
 .../aop/framework/ProxyFactoryBean.java       |  1 +
 .../framework/ReflectiveMethodInvocation.java |  1 +
 .../autoproxy/AbstractAutoProxyCreator.java   |  2 ++
 ...ctBeanFactoryBasedTargetSourceCreator.java |  1 +
 .../target/LazyInitTargetSourceCreator.java   |  2 ++
 .../target/QuickTargetSourceCreator.java      |  2 ++
 .../AsyncExecutionInterceptor.java            |  2 ++
 .../AbstractLazyCreationTargetSource.java     |  2 ++
 .../target/AbstractPoolingTargetSource.java   |  2 ++
 .../aop/target/CommonsPool2TargetSource.java  |  3 ++
 .../aop/target/EmptyTargetSource.java         |  2 ++
 .../aop/target/LazyInitTargetSource.java      |  3 ++
 .../AbstractRefreshableTargetSource.java      |  3 ++
 .../springframework/aop/target/package.html   | 15 ----------
 .../AbstractNestablePropertyAccessor.java     |  3 ++
 .../beans/AbstractPropertyAccessor.java       |  2 ++
 .../beans/BeanMetadataAttributeAccessor.java  |  2 ++
 .../beans/BeanWrapperImpl.java                |  3 ++
 .../beans/DirectFieldAccessor.java            |  2 ++
 .../beans/ExtendedBeanInfoFactory.java        |  2 ++
 .../beans/MutablePropertyValues.java          |  1 +
 .../beans/TypeConverterSupport.java           |  3 ++
 .../AnnotationBeanWiringInfoResolver.java     |  2 ++
 .../AutowiredAnnotationBeanPostProcessor.java |  1 +
 ...erAnnotationAutowireCandidateResolver.java |  1 +
 .../factory/config/AbstractFactoryBean.java   |  1 +
 .../factory/config/BeanDefinitionHolder.java  |  1 +
 .../factory/config/EmbeddedValueResolver.java |  1 +
 .../config/FieldRetrievingFactoryBean.java    |  1 +
 ...ntiationAwareBeanPostProcessorAdapter.java |  4 +++
 .../config/MethodInvokingFactoryBean.java     |  1 +
 .../factory/config/PropertiesFactoryBean.java |  1 +
 .../config/PropertyPathFactoryBean.java       |  1 +
 .../config/PropertyPlaceholderConfigurer.java |  2 ++
 .../config/ServiceLocatorFactoryBean.java     |  1 +
 .../factory/config/YamlMapFactoryBean.java    |  1 +
 .../config/YamlPropertiesFactoryBean.java     |  1 +
 .../serviceloader/ServiceFactoryBean.java     |  2 ++
 .../AbstractAutowireCapableBeanFactory.java   |  8 +++++
 .../support/AbstractBeanDefinition.java       |  3 ++
 .../factory/support/AbstractBeanFactory.java  |  3 ++
 .../support/DefaultListableBeanFactory.java   |  8 +++++
 .../support/DefaultSingletonBeanRegistry.java |  1 +
 .../SimpleAutowireCandidateResolver.java      |  2 ++
 .../support/StaticListableBeanFactory.java    |  1 +
 .../xml/AbstractBeanDefinitionParser.java     |  1 +
 .../xml/DefaultNamespaceHandlerResolver.java  |  1 +
 .../factory/xml/NamespaceHandlerSupport.java  |  2 ++
 .../factory/xml/ResourceEntityResolver.java   |  1 +
 .../SimpleConstructorNamespaceHandler.java    |  2 ++
 .../xml/SimplePropertyNamespaceHandler.java   |  2 ++
 .../cache/caffeine/CaffeineCache.java         |  1 +
 .../cache/caffeine/CaffeineCacheManager.java  |  1 +
 .../cache/ehcache/EhCacheCache.java           |  2 ++
 .../cache/ehcache/EhCacheFactoryBean.java     |  1 +
 .../ehcache/EhCacheManagerFactoryBean.java    |  1 +
 .../cache/jcache/JCacheCache.java             |  2 ++
 .../jcache/JCacheManagerFactoryBean.java      |  1 +
 .../TransactionAwareCacheDecorator.java       |  3 ++
 .../TransactionAwareCacheManagerProxy.java    |  1 +
 .../mail/MailSendException.java               |  1 +
 .../commonj/TimerManagerFactoryBean.java      |  1 +
 .../commonj/TimerManagerTaskScheduler.java    |  1 +
 .../quartz/CronTriggerFactoryBean.java        |  1 +
 .../quartz/JobDetailFactoryBean.java          |  1 +
 .../MethodInvokingJobDetailFactoryBean.java   |  1 +
 .../quartz/SchedulerFactoryBean.java          |  1 +
 .../quartz/SimpleTriggerFactoryBean.java      |  1 +
 .../FreeMarkerConfigurationFactoryBean.java   |  1 +
 .../java/org/springframework/cache/Cache.java |  3 +-
 .../AnnotationCacheOperationSource.java       |  2 ++
 .../annotation/CachingConfigurerSupport.java  |  5 ++++
 .../SpringCacheAnnotationParser.java          |  2 ++
 .../ConcurrentMapCacheFactoryBean.java        |  1 +
 .../concurrent/ConcurrentMapCacheManager.java |  1 +
 ...tationDrivenCacheBeanDefinitionParser.java |  1 +
 .../AbstractFallbackCacheOperationSource.java |  1 +
 ...eanFactoryCacheOperationSourceAdvisor.java |  1 +
 .../interceptor/CacheEvaluationContext.java   |  2 ++
 .../CompositeCacheOperationSource.java        |  1 +
 .../NameMatchCacheOperationSource.java        |  1 +
 .../cache/support/AbstractCacheManager.java   |  1 +
 .../cache/support/CompositeCacheManager.java  |  2 ++
 .../cache/support/NoOpCache.java              |  3 ++
 .../cache/support/NoOpCacheManager.java       |  2 ++
 .../cache/support/SimpleValueWrapper.java     |  1 +
 .../AnnotationConfigBeanDefinitionParser.java |  2 ++
 .../ClassPathBeanDefinitionScanner.java       |  1 +
 .../ComponentScanBeanDefinitionParser.java    |  1 +
 .../annotation/ConfigurationClassParser.java  |  1 +
 ...xtAnnotationAutowireCandidateResolver.java |  1 +
 .../ScannedGenericBeanDefinition.java         |  2 ++
 .../MethodBasedEvaluationContext.java         |  2 ++
 .../StandardBeanExpressionResolver.java       |  1 +
 .../support/AbstractApplicationContext.java   |  3 ++
 .../ApplicationContextAwareProcessor.java     |  2 ++
 .../support/ConversionServiceFactoryBean.java |  1 +
 .../support/GenericApplicationContext.java    |  1 +
 .../PropertySourcesPlaceholderConfigurer.java |  1 +
 ...ReloadableResourceBundleMessageSource.java |  1 +
 .../support/ResourceBundleMessageSource.java  |  1 +
 .../context/support/SimpleThreadScope.java    |  3 ++
 .../context/support/StaticMessageSource.java  |  2 ++
 .../AbstractRemoteSlsbInvokerInterceptor.java |  1 +
 .../access/LocalSlsbInvokerInterceptor.java   |  1 +
 ...LocalStatelessSessionProxyFactoryBean.java |  1 +
 .../SimpleRemoteSlsbInvokerInterceptor.java   |  1 +
 ...emoteStatelessSessionProxyFactoryBean.java |  1 +
 .../joda/DateTimeFormatterFactoryBean.java    |  1 +
 .../DateTimeFormatterFactoryBean.java         |  1 +
 .../support/FormattingConversionService.java  |  3 ++
 ...ormattingConversionServiceFactoryBean.java |  1 +
 .../jmx/access/MBeanProxyFactoryBean.java     |  1 +
 .../jmx/export/MBeanExporter.java             |  1 +
 .../AnnotationJmxAttributeSource.java         |  4 +++
 .../support/ConnectorServerFactoryBean.java   |  1 +
 .../MBeanServerConnectionFactoryBean.java     |  1 +
 .../jmx/support/MBeanServerFactoryBean.java   |  1 +
 .../WebSphereMBeanServerFactoryBean.java      |  1 +
 .../jndi/JndiObjectFactoryBean.java           |  1 +
 .../jndi/JndiObjectTargetSource.java          |  2 ++
 .../jndi/JndiPropertySource.java              |  2 ++
 .../jndi/support/SimpleJndiBeanFactory.java   |  1 +
 .../remoting/rmi/RmiInvocationWrapper.java    |  3 ++
 .../AnnotationAsyncExecutionInterceptor.java  |  1 +
 .../AsyncConfigurationSelector.java           |  2 ++
 .../annotation/AsyncConfigurerSupport.java    |  2 ++
 .../concurrent/ConcurrentTaskScheduler.java   |  1 +
 .../concurrent/ForkJoinPoolFactoryBean.java   |  1 +
 .../ScheduledExecutorFactoryBean.java         |  1 +
 .../ThreadPoolExecutorFactoryBean.java        |  1 +
 .../concurrent/ThreadPoolTaskScheduler.java   |  1 +
 .../AnnotationDrivenBeanDefinitionParser.java |  2 ++
 .../config/TaskExecutorFactoryBean.java       |  1 +
 .../support/SimpleTriggerContext.java         |  3 ++
 .../scripting/bsh/BshScriptFactory.java       |  2 ++
 .../config/ScriptBeanDefinitionParser.java    |  1 +
 .../scripting/groovy/GroovyScriptFactory.java |  3 ++
 .../support/ResourceScriptSource.java         |  1 +
 .../support/ScriptFactoryPostProcessor.java   |  1 +
 .../support/StandardScriptEvaluator.java      |  2 ++
 .../support/StandardScriptFactory.java        |  2 ++
 .../scripting/support/StaticScriptSource.java |  1 +
 .../support/DelegatingThemeSource.java        |  1 +
 .../support/ResourceBundleThemeSource.java    |  1 +
 .../validation/AbstractBindingResult.java     |  9 ++++++
 .../validation/AbstractErrors.java            |  5 +++-
 .../AbstractPropertyBindingResult.java        |  3 ++
 .../validation/BindException.java             |  6 ++++
 .../validation/DataBinder.java                |  4 +++
 .../validation/MapBindingResult.java          |  2 ++
 .../SpringValidatorAdapter.java               |  1 +
 .../core/AttributeAccessorSupport.java        |  2 ++
 .../core/GenericTypeResolver.java             |  1 +
 ...lVariableTableParameterNameDiscoverer.java |  2 ++
 .../PrioritizedParameterNameDiscoverer.java   |  4 +++
 .../springframework/core/ResolvableType.java  |  2 ++
 .../core/SerializableTypeWrapper.java         |  2 ++
 ...dardReflectionParameterNameDiscoverer.java |  5 ++++
 ...liasAwareAnnotationAttributeExtractor.java |  1 +
 .../AnnotationAwareOrderComparator.java       |  5 ++++
 .../DefaultAnnotationAttributeExtractor.java  |  2 ++
 .../MapAnnotationAttributeExtractor.java      |  2 ++
 .../converter/ConvertingComparator.java       |  2 ++
 .../support/ArrayToArrayConverter.java        |  1 +
 .../support/GenericConversionService.java     |  4 +++
 .../convert/support/MapToMapConverter.java    |  1 +
 .../support/ObjectToOptionalConverter.java    |  1 -
 .../core/env/AbstractEnvironment.java         |  4 +++
 .../core/env/AbstractPropertyResolver.java    |  1 +
 .../core/env/CommandLinePropertySource.java   |  1 +
 .../core/env/CompositePropertySource.java     |  2 ++
 .../env/JOptCommandLinePropertySource.java    |  3 ++
 .../core/env/MapPropertySource.java           |  2 ++
 .../core/env/MutablePropertySources.java      |  1 +
 .../core/env/PropertySource.java              |  2 ++
 .../env/PropertySourcesPropertyResolver.java  |  3 ++
 .../env/SimpleCommandLinePropertySource.java  |  3 ++
 .../env/SystemEnvironmentPropertySource.java  |  1 +
 .../core/io/AbstractResource.java             |  2 ++
 .../core/io/ClassPathResource.java            |  1 +
 .../core/io/DefaultResourceLoader.java        |  1 +
 .../PathMatchingResourcePatternResolver.java  |  1 +
 .../core/type/StandardAnnotationMetadata.java |  4 +++
 .../core/type/StandardClassMetadata.java      |  3 ++
 .../core/type/StandardMethodMetadata.java     |  5 ++++
 .../AnnotationMetadataReadingVisitor.java     |  4 +++
 .../MethodMetadataReadingVisitor.java         |  4 +++
 .../type/filter/AnnotationTypeFilter.java     |  2 ++
 .../type/filter/AssignableTypeFilter.java     |  2 ++
 .../org/springframework/lang/Nullable.java    |  5 ++--
 .../springframework/util/CollectionUtils.java |  1 +
 .../util/ConcurrentReferenceHashMap.java      |  2 ++
 .../util/LinkedMultiValueMap.java             |  1 +
 .../util/SystemPropertyUtils.java             |  3 ++
 .../common/CompositeStringExpression.java     |  4 +++
 .../expression/common/LiteralExpression.java  |  4 +++
 .../expression/spel/ast/SpelNodeImpl.java     |  2 ++
 .../spel/standard/SpelExpression.java         | 16 ++++++++++
 .../ReflectiveConstructorResolver.java        |  2 ++
 .../support/ReflectiveMethodResolver.java     |  1 +
 .../support/ReflectivePropertyAccessor.java   |  2 ++
 .../support/StandardEvaluationContext.java    |  1 +
 .../spel/support/StandardTypeConverter.java   |  1 +
 .../jdbc/core/JdbcOperations.java             |  4 +++
 .../jdbc/core/JdbcTemplate.java               | 23 +++++++++++++++
 .../jdbc/core/ParameterMapper.java            |  3 --
 .../jdbc/core/SingleColumnRowMapper.java      |  1 +
 .../metadata/Db2CallMetaDataProvider.java     |  1 +
 .../metadata/DerbyCallMetaDataProvider.java   |  1 +
 .../metadata/GenericCallMetaDataProvider.java |  6 ++++
 .../GenericTableMetaDataProvider.java         |  6 ++++
 .../metadata/OracleCallMetaDataProvider.java  |  2 ++
 .../metadata/OracleTableMetaDataProvider.java |  1 +
 .../PostgresCallMetaDataProvider.java         |  1 +
 .../SqlServerCallMetaDataProvider.java        |  1 +
 .../metadata/SybaseCallMetaDataProvider.java  |  1 +
 .../AbstractSqlParameterSource.java           |  2 ++
 .../BeanPropertySqlParameterSource.java       |  1 +
 .../namedparam/EmptySqlParameterSource.java   |  4 +++
 .../namedparam/MapSqlParameterSource.java     |  1 +
 .../NamedParameterJdbcOperations.java         |  2 ++
 .../NamedParameterJdbcTemplate.java           | 10 +++++++
 ...bstractLobStreamingResultSetExtractor.java |  2 ++
 .../embedded/EmbeddedDatabaseFactoryBean.java |  1 +
 .../IsolationLevelDataSourceRouter.java       |  2 ++
 .../jdbc/object/MappingSqlQuery.java          |  1 +
 .../object/MappingSqlQueryWithParameters.java |  1 +
 .../jdbc/object/SqlFunction.java              |  1 +
 ...bstractFallbackSQLExceptionTranslator.java |  1 +
 .../jdbc/support/GeneratedKeyHolder.java      |  3 ++
 .../SQLErrorCodeSQLExceptionTranslator.java   |  1 +
 .../SQLStateSQLExceptionTranslator.java       |  1 +
 .../jdbc/support/lob/AbstractLobHandler.java  |  6 ++++
 .../jdbc/support/lob/DefaultLobHandler.java   |  3 ++
 .../jdbc/support/xml/Jdbc4SqlXmlHandler.java  |  8 +++++
 .../jdbc/core/JdbcOperationsExtensions.kt     |  2 +-
 .../org/springframework/jms/JmsException.java |  1 +
 .../AbstractListenerContainerParser.java      |  1 +
 ...notationDrivenJmsBeanDefinitionParser.java |  1 +
 .../connection/ConnectionFactoryUtils.java    |  6 ++++
 .../jms/core/JmsMessagingTemplate.java        | 14 +++++++++
 .../springframework/jms/core/JmsTemplate.java | 29 ++++++++++++++++++-
 ...stractPollingMessageListenerContainer.java |  2 ++
 .../adapter/MessageListenerAdapter.java       |  1 -
 .../endpoint/JmsMessageEndpointManager.java   |  3 ++
 .../remoting/JmsInvokerProxyFactoryBean.java  |  1 +
 .../converter/AbstractMessageConverter.java   |  4 +++
 .../converter/CompositeMessageConverter.java  |  4 +++
 .../converter/DefaultContentTypeResolver.java |  1 +
 .../converter/GenericMessageConverter.java    |  2 ++
 .../MappingJackson2MessageConverter.java      |  1 +
 .../converter/SimpleMessageConverter.java     |  1 +
 .../converter/StringMessageConverter.java     |  1 +
 ...DestinationResolvingMessagingTemplate.java |  7 +++++
 .../AbstractMessageReceivingTemplate.java     |  4 +++
 .../core/AbstractMessagingTemplate.java       |  8 +++++
 .../core/GenericMessagingTemplate.java        |  4 +++
 .../DestinationPatternsMessageCondition.java  |  1 +
 ...tractNamedValueMethodArgumentResolver.java |  1 +
 ...inationVariableMethodArgumentResolver.java |  2 ++
 .../support/HeaderMethodArgumentResolver.java |  1 +
 .../HeadersMethodArgumentResolver.java        |  2 ++
 .../support/PayloadArgumentResolver.java      |  1 +
 ...andlerMethodArgumentResolverComposite.java |  1 +
 ...dlerMethodReturnValueHandlerComposite.java |  1 +
 .../simp/SimpMessageMappingInfo.java          |  1 +
 .../simp/SimpMessageTypeMessageCondition.java |  2 ++
 .../messaging/simp/SimpSessionScope.java      |  3 ++
 .../SendToMethodReturnValueHandler.java       |  1 +
 .../SimpAnnotationMethodMessageHandler.java   |  3 ++
 .../simp/stomp/DefaultStompSession.java       |  1 +
 .../simp/stomp/StompHeaderAccessor.java       |  2 ++
 .../messaging/simp/stomp/StompHeaders.java    |  1 +
 .../user/DefaultUserDestinationResolver.java  |  1 +
 .../simp/user/MultiServerUserRegistry.java    |  2 ++
 .../MonoToListenableFutureAdapter.java        |  1 +
 .../HibernateExceptionTranslator.java         |  2 ++
 .../orm/hibernate5/HibernateTemplate.java     |  5 ++++
 .../hibernate5/LocalSessionFactoryBean.java   |  1 +
 .../jpa/AbstractEntityManagerFactoryBean.java |  4 +++
 .../orm/jpa/DefaultJpaDialect.java            |  4 +++
 ...ocalContainerEntityManagerFactoryBean.java |  1 +
 .../jpa/support/SharedEntityManagerBean.java  |  1 +
 .../jpa/vendor/AbstractJpaVendorAdapter.java  |  3 ++
 .../orm/jpa/vendor/EclipseLinkJpaDialect.java |  1 +
 .../orm/jpa/vendor/HibernateJpaDialect.java   |  1 +
 .../HibernateJpaSessionFactoryBean.java       |  2 ++
 .../mock/web/MockServletContext.java          |  1 +
 .../context/cache/DefaultContextCache.java    |  1 +
 .../context/support/DefaultTestContext.java   |  3 ++
 .../TestContextTransactionUtils.java          |  1 +
 ...rverContainerContextCustomizerFactory.java |  2 ++
 .../reactive/server/FluxExchangeResult.java   |  3 ++
 .../setup/MockMvcConfigurerAdapter.java       |  2 ++
 .../setup/StandaloneMockMvcBuilder.java       |  1 +
 .../setup/StubWebApplicationContext.java      |  4 +++
 ...ChainedPersistenceExceptionTranslator.java |  2 ++
 .../dao/support/DataAccessUtils.java          |  1 +
 .../jca/cci/core/CciTemplate.java             |  3 ++
 .../support/LocalConnectionFactoryBean.java   |  1 +
 .../support/ResourceAdapterFactoryBean.java   |  1 +
 .../AnnotationTransactionAttributeSource.java |  2 ++
 .../Ejb3TransactionAnnotationParser.java      |  2 ++
 .../JtaTransactionAnnotationParser.java       |  2 ++
 .../SpringTransactionAnnotationParser.java    |  2 ++
 .../AnnotationDrivenBeanDefinitionParser.java |  2 ++
 .../JtaTransactionManagerFactoryBean.java     |  1 +
 ...actFallbackTransactionAttributeSource.java |  1 +
 ...toryTransactionAttributeSourceAdvisor.java |  1 +
 .../DelegatingTransactionAttribute.java       |  2 ++
 ...MatchAlwaysTransactionAttributeSource.java |  1 +
 .../MethodMapTransactionAttributeSource.java  |  1 +
 .../NameMatchTransactionAttributeSource.java  |  1 +
 .../interceptor/TransactionAspectSupport.java |  1 +
 .../TransactionAttributeSourceAdvisor.java    |  1 +
 .../jta/WebLogicJtaTransactionManager.java    |  2 ++
 .../jta/WebSphereUowTransactionManager.java   |  1 +
 .../DelegatingTransactionDefinition.java      |  2 ++
 .../support/SimpleTransactionScope.java       |  4 +++
 .../TransactionCallbackWithoutResult.java     |  2 ++
 .../support/TransactionTemplate.java          |  1 +
 .../org/springframework/http/HttpHeaders.java |  1 +
 .../BufferingClientHttpRequestWrapper.java    |  2 ++
 .../client/support/HttpRequestWrapper.java    |  2 ++
 .../http/client/support/ProxyFactoryBean.java |  1 +
 .../ResourceHttpMessageConverter.java         |  1 +
 .../AbstractJackson2HttpMessageConverter.java |  1 +
 .../http/converter/json/GsonFactoryBean.java  |  1 +
 .../json/Jackson2ObjectMapperFactoryBean.java |  1 +
 .../server/ServletServerHttpResponse.java     |  2 ++
 .../DefaultServerHttpRequestBuilder.java      |  1 +
 .../reactive/ServerHttpRequestDecorator.java  |  2 ++
 .../reactive/ServletServerHttpRequest.java    |  1 +
 .../reactive/UndertowServerHttpRequest.java   |  1 +
 .../caucho/HessianClientInterceptor.java      |  1 +
 .../caucho/HessianProxyFactoryBean.java       |  1 +
 .../HttpInvokerProxyFactoryBean.java          |  1 +
 .../jaxws/JaxWsPortProxyFactoryBean.java      |  1 +
 .../jaxws/LocalJaxWsServiceFactoryBean.java   |  1 +
 .../ContentNegotiationManagerFactoryBean.java |  1 +
 .../ParameterContentNegotiationStrategy.java  |  2 ++
 ...thExtensionContentNegotiationStrategy.java |  1 +
 ...thExtensionContentNegotiationStrategy.java |  1 +
 .../web/bind/EscapedErrors.java               |  5 ++++
 .../support/DefaultSessionAttributeStore.java |  1 +
 .../support/WebExchangeBindException.java     |  8 +++++
 .../web/client/AsyncRestTemplate.java         |  3 ++
 .../web/client/RestTemplate.java              | 15 ++++++++++
 .../AbstractRequestAttributesScope.java       |  3 ++
 .../web/context/request/FacesWebRequest.java  |  6 ++++
 .../web/context/request/RequestScope.java     |  3 ++
 .../context/request/ServletWebRequest.java    |  6 ++++
 .../web/context/request/SessionScope.java     |  2 ++
 .../context/request/async/DeferredResult.java |  2 ++
 ...tractRefreshableWebApplicationContext.java |  1 +
 .../ContextExposingHttpServletRequest.java    |  1 +
 .../support/GenericWebApplicationContext.java |  3 ++
 .../support/ServletConfigPropertySource.java  |  2 ++
 .../ServletContextAttributeFactoryBean.java   |  1 +
 .../ServletContextParameterFactoryBean.java   |  1 +
 .../support/ServletContextPropertySource.java |  2 ++
 .../support/ServletContextResource.java       |  2 ++
 .../context/support/ServletContextScope.java  |  4 +++
 .../support/StaticWebApplicationContext.java  |  1 +
 .../cors/UrlBasedCorsConfigurationSource.java |  1 +
 .../UrlBasedCorsConfigurationSource.java      |  1 +
 ...tractNamedValueMethodArgumentResolver.java |  1 +
 .../AbstractWebArgumentResolverAdapter.java   |  1 +
 .../ErrorsMethodArgumentResolver.java         |  1 +
 ...ExpressionValueMethodArgumentResolver.java |  1 +
 .../method/annotation/MapMethodProcessor.java |  1 +
 .../ModelAttributeMethodProcessor.java        |  1 +
 .../annotation/ModelMethodProcessor.java      |  1 +
 .../RequestHeaderMethodArgumentResolver.java  |  1 +
 .../RequestParamMethodArgumentResolver.java   |  1 +
 ...andlerMethodArgumentResolverComposite.java |  1 +
 .../web/server/ResponseStatusException.java   |  1 +
 .../i18n/FixedLocaleContextResolver.java      |  1 +
 .../web/util/HierarchicalUriComponents.java   |  2 ++
 .../web/util/OpaqueUriComponents.java         |  5 ++++
 .../web/util/ServletContextPropertyUtils.java |  2 ++
 .../server/ResourceHandlerFunction.java       |  2 ++
 .../resource/GzipResourceResolver.java        | 13 +++++++++
 .../resource/VersionResourceResolver.java     |  1 +
 .../AbstractNameValueExpression.java          |  3 ++
 .../condition/HeadersRequestCondition.java    |  2 ++
 .../result/condition/NameValueExpression.java |  3 ++
 .../condition/ProducesRequestCondition.java   |  2 ++
 .../RequestMethodsRequestCondition.java       |  2 ++
 .../result/method/RequestMappingInfo.java     |  2 ++
 .../web/reactive/result/view/Rendering.java   |  1 -
 .../AbstractListenerWebSocketSession.java     |  1 +
 .../AnnotationDrivenBeanDefinitionParser.java |  2 ++
 .../config/CorsBeanDefinitionParser.java      |  2 ++
 ...ultServletHandlerBeanDefinitionParser.java |  2 ++
 .../InterceptorsBeanDefinitionParser.java     |  2 ++
 .../DelegatingWebMvcConfiguration.java        |  3 ++
 .../annotation/WebMvcConfigurerAdapter.java   |  3 ++
 .../annotation/WebMvcConfigurerComposite.java |  2 ++
 .../AbstractDetectingUrlHandlerMapping.java   |  5 +---
 .../AbstractHandlerExceptionResolver.java     |  1 +
 .../handler/AbstractHandlerMapping.java       |  3 ++
 ...bstractHandlerMethodExceptionResolver.java |  1 +
 .../handler/AbstractUrlHandlerMapping.java    |  1 +
 .../handler/HandlerMappingIntrospector.java   |  1 +
 .../SimpleMappingExceptionResolver.java       |  1 +
 .../handler/SimpleServletHandlerAdapter.java  |  2 ++
 .../servlet/i18n/CookieLocaleResolver.java    |  2 ++
 .../web/servlet/i18n/FixedLocaleResolver.java |  1 +
 .../servlet/i18n/SessionLocaleResolver.java   |  1 +
 .../web/servlet/mvc/AbstractController.java   |  1 +
 .../mvc/HttpRequestHandlerAdapter.java        |  2 ++
 .../mvc/SimpleControllerHandlerAdapter.java   |  2 ++
 .../ResponseStatusExceptionResolver.java      |  1 +
 .../condition/CompositeRequestCondition.java  |  2 ++
 .../condition/ConsumesRequestCondition.java   |  1 +
 .../condition/HeadersRequestCondition.java    |  2 ++
 .../mvc/condition/ParamsRequestCondition.java |  2 ++
 .../condition/PatternsRequestCondition.java   |  1 +
 .../condition/ProducesRequestCondition.java   |  1 +
 .../mvc/condition/RequestConditionHolder.java |  1 +
 .../RequestMethodsRequestCondition.java       |  1 +
 .../method/AbstractHandlerMethodAdapter.java  |  1 +
 .../mvc/method/RequestMappingInfo.java        |  1 +
 ...tractMappingJacksonResponseBodyAdvice.java |  1 +
 .../annotation/HttpEntityMethodProcessor.java |  1 +
 ...trixVariableMapMethodArgumentResolver.java |  1 +
 .../MatrixVariableMethodArgumentResolver.java |  2 ++
 .../PathVariableMethodArgumentResolver.java   |  1 +
 ...equestAttributeMethodArgumentResolver.java |  2 ++
 .../RequestMappingHandlerMapping.java         |  2 ++
 .../RequestPartMethodArgumentResolver.java    |  1 +
 .../RequestResponseBodyAdviceChain.java       |  2 ++
 ...vletCookieValueMethodArgumentResolver.java |  1 +
 ...essionAttributeMethodArgumentResolver.java |  2 ++
 .../DefaultHandlerExceptionResolver.java      |  1 +
 .../resource/AbstractResourceResolver.java    |  2 ++
 .../resource/AbstractVersionStrategy.java     |  4 +++
 .../DefaultResourceResolverChain.java         |  2 ++
 .../resource/GzipResourceResolver.java        | 13 +++++++++
 .../resource/ResourceHttpRequestHandler.java  |  1 +
 .../resource/VersionResourceResolver.java     |  1 +
 .../support/AbstractFlashMapManager.java      |  1 +
 .../support/SessionFlashMapManager.java       |  2 ++
 .../web/servlet/tags/BindTag.java             |  1 +
 .../web/servlet/tags/EvalTag.java             |  1 +
 .../form/AbstractDataBoundFormElementTag.java |  2 ++
 .../view/AbstractCachingViewResolver.java     |  2 ++
 .../servlet/view/BeanNameViewResolver.java    |  2 ++
 .../view/ContentNegotiatingViewResolver.java  |  2 ++
 .../servlet/view/ViewResolverComposite.java   |  2 ++
 .../web/socket/WebSocketHttpHeaders.java      |  1 +
 .../web/socket/WebSocketSession.java          |  1 -
 .../adapter/AbstractWebSocketSession.java     |  1 +
 .../adapter/NativeWebSocketSession.java       |  2 +-
 .../adapter/jetty/JettyWebSocketSession.java  |  1 +
 .../standard/StandardWebSocketSession.java    |  1 +
 .../config/HandlersBeanDefinitionParser.java  |  2 ++
 .../WebSocketConfigurationSupport.java        |  1 +
 .../handler/WebSocketSessionDecorator.java    |  2 ++
 .../messaging/DefaultSimpUserRegistry.java    |  2 ++
 .../StompSubProtocolErrorHandler.java         |  1 +
 .../messaging/StompSubProtocolHandler.java    |  1 +
 ...bSocketAnnotationMethodMessageHandler.java |  1 +
 .../ServletServerContainerFactoryBean.java    |  1 +
 .../client/WebSocketClientSockJsSession.java  |  1 +
 .../frame/Jackson2SockJsMessageCodec.java     |  3 ++
 .../sockjs/support/AbstractSockJsService.java |  1 +
 .../support/SockJsHttpRequestHandler.java     |  2 ++
 .../JsonpReceivingTransportHandler.java       |  2 ++
 .../handler/XhrReceivingTransportHandler.java |  2 ++
 .../session/WebSocketServerSockJsSession.java |  4 ++-
 488 files changed, 1016 insertions(+), 34 deletions(-)
 delete mode 100644 spring-aop/src/main/java/org/springframework/aop/target/package.html

diff --git a/spring-aop/src/main/java/org/springframework/aop/TargetSource.java b/spring-aop/src/main/java/org/springframework/aop/TargetSource.java
index cc4da039b4b..61afc9d4bba 100644
--- a/spring-aop/src/main/java/org/springframework/aop/TargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/TargetSource.java
@@ -42,6 +42,7 @@ public interface TargetSource extends TargetClassAware {
 	 * @return the type of targets returned by this {@link TargetSource}
 	 */
 	@Override
+	@Nullable
 	Class<?> getTargetClass();
 
 	/**
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJAdviceParameterNameDiscoverer.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJAdviceParameterNameDiscoverer.java
index 1ec800eb026..6e0c4ffe3d5 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJAdviceParameterNameDiscoverer.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/AspectJAdviceParameterNameDiscoverer.java
@@ -222,6 +222,7 @@ public class AspectJAdviceParameterNameDiscoverer implements ParameterNameDiscov
 	 * @return the parameter names
 	 */
 	@Override
+	@Nullable
 	public String[] getParameterNames(Method method) {
 		this.argumentTypes = method.getParameterTypes();
 		this.numberOfRemainingUnboundArguments = this.argumentTypes.length;
@@ -310,6 +311,7 @@ public class AspectJAdviceParameterNameDiscoverer implements ParameterNameDiscov
 	 * {@link #setRaiseExceptions(boolean) raiseExceptions} has been set to {@code true}
 	 */
 	@Override
+	@Nullable
 	public String[] getParameterNames(Constructor<?> ctor) {
 		if (this.raiseExceptions) {
 			throw new UnsupportedOperationException("An advice method can never be a constructor");
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/SimpleAspectInstanceFactory.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/SimpleAspectInstanceFactory.java
index 95378f9e67a..c5a22911a82 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/SimpleAspectInstanceFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/SimpleAspectInstanceFactory.java
@@ -20,6 +20,7 @@ import java.lang.reflect.InvocationTargetException;
 
 import org.springframework.aop.framework.AopConfigException;
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 
@@ -76,6 +77,7 @@ public class SimpleAspectInstanceFactory implements AspectInstanceFactory {
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getAspectClassLoader() {
 		return this.aspectClass.getClassLoader();
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/SingletonAspectInstanceFactory.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/SingletonAspectInstanceFactory.java
index d311f620068..71fb7145032 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/SingletonAspectInstanceFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/SingletonAspectInstanceFactory.java
@@ -19,6 +19,7 @@ package org.springframework.aop.aspectj;
 import java.io.Serializable;
 
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -53,6 +54,7 @@ public class SingletonAspectInstanceFactory implements AspectInstanceFactory, Se
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getAspectClassLoader() {
 		return this.aspectInstance.getClass().getClassLoader();
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactory.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactory.java
index 6065e0bed23..70b928ab2fb 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactory.java
@@ -261,6 +261,7 @@ public abstract class AbstractAspectJAdvisorFactory implements AspectJAdvisorFac
 	private static class AspectJAnnotationParameterNameDiscoverer implements ParameterNameDiscoverer {
 
 		@Override
+		@Nullable
 		public String[] getParameterNames(Method method) {
 			if (method.getParameterCount() == 0) {
 				return new String[0];
@@ -283,6 +284,7 @@ public abstract class AbstractAspectJAdvisorFactory implements AspectJAdvisorFac
 		}
 
 		@Override
+		@Nullable
 		public String[] getParameterNames(Constructor<?> ctor) {
 			throw new UnsupportedOperationException("Spring AOP cannot handle constructor advice");
 		}
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/BeanFactoryAspectInstanceFactory.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/BeanFactoryAspectInstanceFactory.java
index e7a2dcd5783..ccd581cf7b6 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/BeanFactoryAspectInstanceFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/BeanFactoryAspectInstanceFactory.java
@@ -91,6 +91,7 @@ public class BeanFactoryAspectInstanceFactory implements MetadataAwareAspectInst
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getAspectClassLoader() {
 		return (this.beanFactory instanceof ConfigurableBeanFactory ?
 				((ConfigurableBeanFactory) this.beanFactory).getBeanClassLoader() :
@@ -103,6 +104,7 @@ public class BeanFactoryAspectInstanceFactory implements MetadataAwareAspectInst
 	}
 
 	@Override
+	@Nullable
 	public Object getAspectCreationMutex() {
 		if (this.beanFactory.isSingleton(this.name)) {
 			// Rely on singleton semantics provided by the factory -> no local lock.
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/LazySingletonAspectInstanceFactoryDecorator.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/LazySingletonAspectInstanceFactoryDecorator.java
index e6bc38f37aa..3a6af19a2ea 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/LazySingletonAspectInstanceFactoryDecorator.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/LazySingletonAspectInstanceFactoryDecorator.java
@@ -74,6 +74,7 @@ public class LazySingletonAspectInstanceFactoryDecorator implements MetadataAwar
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getAspectClassLoader() {
 		return this.maaif.getAspectClassLoader();
 	}
@@ -84,6 +85,7 @@ public class LazySingletonAspectInstanceFactoryDecorator implements MetadataAwar
 	}
 
 	@Override
+	@Nullable
 	public Object getAspectCreationMutex() {
 		return this.maaif.getAspectCreationMutex();
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/ReflectiveAspectJAdvisorFactory.java b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/ReflectiveAspectJAdvisorFactory.java
index 73d58a01b4e..4c319683bc5 100644
--- a/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/ReflectiveAspectJAdvisorFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/ReflectiveAspectJAdvisorFactory.java
@@ -184,6 +184,7 @@ public class ReflectiveAspectJAdvisorFactory extends AbstractAspectJAdvisorFacto
 
 
 	@Override
+	@Nullable
 	public Advisor getAdvisor(Method candidateAdviceMethod, MetadataAwareAspectInstanceFactory aspectInstanceFactory,
 			int declarationOrderInAspect, String aspectName) {
 
@@ -218,6 +219,7 @@ public class ReflectiveAspectJAdvisorFactory extends AbstractAspectJAdvisorFacto
 
 
 	@Override
+	@Nullable
 	public Advice getAdvice(Method candidateAdviceMethod, AspectJExpressionPointcut expressionPointcut,
 			MetadataAwareAspectInstanceFactory aspectInstanceFactory, int declarationOrder, String aspectName) {
 
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/AdvisorComponentDefinition.java b/spring-aop/src/main/java/org/springframework/aop/config/AdvisorComponentDefinition.java
index 44d9f34c4b3..03034f48fbe 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/AdvisorComponentDefinition.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/AdvisorComponentDefinition.java
@@ -110,6 +110,7 @@ public class AdvisorComponentDefinition extends AbstractComponentDefinition {
 	}
 
 	@Override
+	@Nullable
 	public Object getSource() {
 		return this.advisorDefinition.getSource();
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/AspectJAutoProxyBeanDefinitionParser.java b/spring-aop/src/main/java/org/springframework/aop/config/AspectJAutoProxyBeanDefinitionParser.java
index e84ecea24ec..527f0504fb5 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/AspectJAutoProxyBeanDefinitionParser.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/AspectJAutoProxyBeanDefinitionParser.java
@@ -25,6 +25,7 @@ import org.springframework.beans.factory.config.TypedStringValue;
 import org.springframework.beans.factory.support.ManagedList;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link BeanDefinitionParser} for the {@code aspectj-autoproxy} tag,
@@ -38,6 +39,7 @@ import org.springframework.beans.factory.xml.ParserContext;
 class AspectJAutoProxyBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		AopNamespaceUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(parserContext, element);
 		extendBeanDefinition(element, parserContext);
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/ConfigBeanDefinitionParser.java b/spring-aop/src/main/java/org/springframework/aop/config/ConfigBeanDefinitionParser.java
index 08c8a2591e2..90fe0f0543a 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/ConfigBeanDefinitionParser.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/ConfigBeanDefinitionParser.java
@@ -97,6 +97,7 @@ class ConfigBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		CompositeComponentDefinition compositeDef =
 				new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/MethodLocatingFactoryBean.java b/spring-aop/src/main/java/org/springframework/aop/config/MethodLocatingFactoryBean.java
index 78407f87dc0..993bad509e8 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/MethodLocatingFactoryBean.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/MethodLocatingFactoryBean.java
@@ -84,6 +84,7 @@ public class MethodLocatingFactoryBean implements FactoryBean<Method>, BeanFacto
 
 
 	@Override
+	@Nullable
 	public Method getObject() throws Exception {
 		return this.method;
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/PointcutComponentDefinition.java b/spring-aop/src/main/java/org/springframework/aop/config/PointcutComponentDefinition.java
index 3cbf472e588..7b82314e64f 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/PointcutComponentDefinition.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/PointcutComponentDefinition.java
@@ -18,6 +18,7 @@ package org.springframework.aop.config;
 
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.parsing.AbstractComponentDefinition;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -62,6 +63,7 @@ public class PointcutComponentDefinition extends AbstractComponentDefinition {
 	}
 
 	@Override
+	@Nullable
 	public Object getSource() {
 		return this.pointcutDefinition.getSource();
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/config/SimpleBeanFactoryAwareAspectInstanceFactory.java b/spring-aop/src/main/java/org/springframework/aop/config/SimpleBeanFactoryAwareAspectInstanceFactory.java
index 2afacfe91ba..b432821bf36 100644
--- a/spring-aop/src/main/java/org/springframework/aop/config/SimpleBeanFactoryAwareAspectInstanceFactory.java
+++ b/spring-aop/src/main/java/org/springframework/aop/config/SimpleBeanFactoryAwareAspectInstanceFactory.java
@@ -69,6 +69,7 @@ public class SimpleBeanFactoryAwareAspectInstanceFactory implements AspectInstan
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getAspectClassLoader() {
 		if (this.beanFactory instanceof ConfigurableBeanFactory) {
 			return ((ConfigurableBeanFactory) this.beanFactory).getBeanClassLoader();
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/AbstractSingletonProxyFactoryBean.java b/spring-aop/src/main/java/org/springframework/aop/framework/AbstractSingletonProxyFactoryBean.java
index 76264439479..f26af490880 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/AbstractSingletonProxyFactoryBean.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/AbstractSingletonProxyFactoryBean.java
@@ -221,6 +221,7 @@ public abstract class AbstractSingletonProxyFactoryBean extends ProxyConfig
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getObjectType() {
 		if (this.proxy != null) {
 			return this.proxy.getClass();
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/ProxyFactoryBean.java b/spring-aop/src/main/java/org/springframework/aop/framework/ProxyFactoryBean.java
index d224a93a1a6..a806b4037e8 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/ProxyFactoryBean.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/ProxyFactoryBean.java
@@ -247,6 +247,7 @@ public class ProxyFactoryBean extends ProxyCreatorSupport
 	 * @return a fresh AOP proxy reflecting the current state of this factory
 	 */
 	@Override
+	@Nullable
 	public Object getObject() throws BeansException {
 		initializeAdvisorChain();
 		if (isSingleton()) {
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/ReflectiveMethodInvocation.java b/spring-aop/src/main/java/org/springframework/aop/framework/ReflectiveMethodInvocation.java
index bad0ad68196..c8a2ece2731 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/ReflectiveMethodInvocation.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/ReflectiveMethodInvocation.java
@@ -262,6 +262,7 @@ public class ReflectiveMethodInvocation implements ProxyMethodInvocation, Clonea
 	}
 
 	@Override
+	@Nullable
 	public Object getUserAttribute(String key) {
 		return (this.userAttributes != null ? this.userAttributes.get(key) : null);
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java
index 81b4714d3a8..ee7d751b7f2 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java
@@ -218,6 +218,7 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 
 
 	@Override
+	@Nullable
 	public Class<?> predictBeanType(Class<?> beanClass, String beanName) {
 		if (this.proxyTypes.isEmpty()) {
 			return null;
@@ -227,6 +228,7 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 	}
 
 	@Override
+	@Nullable
 	public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName) throws BeansException {
 		return null;
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/AbstractBeanFactoryBasedTargetSourceCreator.java b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/AbstractBeanFactoryBasedTargetSourceCreator.java
index 09c2bff44d8..e339e716b4d 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/AbstractBeanFactoryBasedTargetSourceCreator.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/AbstractBeanFactoryBasedTargetSourceCreator.java
@@ -89,6 +89,7 @@ public abstract class AbstractBeanFactoryBasedTargetSourceCreator
 	//---------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public final TargetSource getTargetSource(Class<?> beanClass, String beanName) {
 		AbstractBeanFactoryBasedTargetSource targetSource =
 				createBeanFactoryBasedTargetSource(beanClass, beanName);
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/LazyInitTargetSourceCreator.java b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/LazyInitTargetSourceCreator.java
index 55d091394cb..47872f6cada 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/LazyInitTargetSourceCreator.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/LazyInitTargetSourceCreator.java
@@ -20,6 +20,7 @@ import org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource;
 import org.springframework.aop.target.LazyInitTargetSource;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.lang.Nullable;
 
 /**
  * TargetSourceCreator that enforces a LazyInitTargetSource for each bean
@@ -59,6 +60,7 @@ public class LazyInitTargetSourceCreator extends AbstractBeanFactoryBasedTargetS
 	}
 
 	@Override
+	@Nullable
 	protected AbstractBeanFactoryBasedTargetSource createBeanFactoryBasedTargetSource(
 			Class<?> beanClass, String beanName) {
 
diff --git a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/QuickTargetSourceCreator.java b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/QuickTargetSourceCreator.java
index 46d6fdbd607..6101658fa45 100644
--- a/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/QuickTargetSourceCreator.java
+++ b/spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/target/QuickTargetSourceCreator.java
@@ -20,6 +20,7 @@ import org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource;
 import org.springframework.aop.target.CommonsPool2TargetSource;
 import org.springframework.aop.target.PrototypeTargetSource;
 import org.springframework.aop.target.ThreadLocalTargetSource;
+import org.springframework.lang.Nullable;
 
 /**
  * Convenient TargetSourceCreator using bean name prefixes to create one of three
@@ -41,6 +42,7 @@ public class QuickTargetSourceCreator extends AbstractBeanFactoryBasedTargetSour
 	public static final String PREFIX_PROTOTYPE = "!";
 
 	@Override
+	@Nullable
 	protected final AbstractBeanFactoryBasedTargetSource createBeanFactoryBasedTargetSource(
 			Class<?> beanClass, String beanName) {
 
diff --git a/spring-aop/src/main/java/org/springframework/aop/interceptor/AsyncExecutionInterceptor.java b/spring-aop/src/main/java/org/springframework/aop/interceptor/AsyncExecutionInterceptor.java
index 1e260f26d42..d69442e4743 100644
--- a/spring-aop/src/main/java/org/springframework/aop/interceptor/AsyncExecutionInterceptor.java
+++ b/spring-aop/src/main/java/org/springframework/aop/interceptor/AsyncExecutionInterceptor.java
@@ -138,6 +138,7 @@ public class AsyncExecutionInterceptor extends AsyncExecutionAspectSupport imple
 	 * @see #determineAsyncExecutor(Method)
 	 */
 	@Override
+	@Nullable
 	protected String getExecutorQualifier(Method method) {
 		return null;
 	}
@@ -151,6 +152,7 @@ public class AsyncExecutionInterceptor extends AsyncExecutionAspectSupport imple
 	 * @see #DEFAULT_TASK_EXECUTOR_BEAN_NAME
 	 */
 	@Override
+	@Nullable
 	protected Executor getDefaultExecutor(@Nullable BeanFactory beanFactory) {
 		Executor defaultExecutor = super.getDefaultExecutor(beanFactory);
 		return (defaultExecutor != null ? defaultExecutor : new SimpleAsyncTaskExecutor());
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/AbstractLazyCreationTargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/AbstractLazyCreationTargetSource.java
index 97f3ae8732d..4c23c54c365 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/AbstractLazyCreationTargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/AbstractLazyCreationTargetSource.java
@@ -20,6 +20,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.aop.TargetSource;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link org.springframework.aop.TargetSource} implementation that will
@@ -65,6 +66,7 @@ public abstract class AbstractLazyCreationTargetSource implements TargetSource {
 	 * @see #isInitialized()
 	 */
 	@Override
+	@Nullable
 	public synchronized Class<?> getTargetClass() {
 		return (this.lazyTarget != null ? this.lazyTarget.getClass() : null);
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/AbstractPoolingTargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/AbstractPoolingTargetSource.java
index 897c05aa37b..bfd4a5f147d 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/AbstractPoolingTargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/AbstractPoolingTargetSource.java
@@ -22,6 +22,7 @@ import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanInitializationException;
 import org.springframework.beans.factory.DisposableBean;
+import org.springframework.lang.Nullable;
 
 /**
  * Abstract base class for pooling {@link org.springframework.aop.TargetSource}
@@ -100,6 +101,7 @@ public abstract class AbstractPoolingTargetSource extends AbstractPrototypeBased
 	 * APIs, so we're forgiving with our exception signature
 	 */
 	@Override
+	@Nullable
 	public abstract Object getTarget() throws Exception;
 
 	/**
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/CommonsPool2TargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/CommonsPool2TargetSource.java
index 67748223213..3e8183be219 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/CommonsPool2TargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/CommonsPool2TargetSource.java
@@ -23,6 +23,8 @@ import org.apache.commons.pool2.impl.DefaultPooledObject;
 import org.apache.commons.pool2.impl.GenericObjectPool;
 import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@link org.springframework.aop.TargetSource} implementation that holds
  * objects in a configurable Apache Commons2 Pool.
@@ -78,6 +80,7 @@ public class CommonsPool2TargetSource extends AbstractPoolingTargetSource implem
 	/**
 	 * The Apache Commons {@code ObjectPool} used to pool target objects
 	 */
+	@Nullable
 	private ObjectPool pool;
 
 
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/EmptyTargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/EmptyTargetSource.java
index fa2e6ad9f00..344d33a8bb3 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/EmptyTargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/EmptyTargetSource.java
@@ -92,6 +92,7 @@ public class EmptyTargetSource implements TargetSource, Serializable {
 	 * Always returns the specified target Class, or {@code null} if none.
 	 */
 	@Override
+	@Nullable
 	public Class<?> getTargetClass() {
 		return this.targetClass;
 	}
@@ -108,6 +109,7 @@ public class EmptyTargetSource implements TargetSource, Serializable {
 	 * Always returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	public Object getTarget() {
 		return null;
 	}
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/LazyInitTargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/LazyInitTargetSource.java
index bad59acf1b0..e31a83c1922 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/LazyInitTargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/LazyInitTargetSource.java
@@ -17,6 +17,7 @@
 package org.springframework.aop.target;
 
 import org.springframework.beans.BeansException;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link org.springframework.aop.TargetSource} that lazily accesses a
@@ -59,10 +60,12 @@ import org.springframework.beans.BeansException;
 @SuppressWarnings("serial")
 public class LazyInitTargetSource extends AbstractBeanFactoryBasedTargetSource {
 
+	@Nullable
 	private Object target;
 
 
 	@Override
+	@Nullable
 	public synchronized Object getTarget() throws BeansException {
 		if (this.target == null) {
 			this.target = getBeanFactory().getBean(getTargetBeanName());
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/dynamic/AbstractRefreshableTargetSource.java b/spring-aop/src/main/java/org/springframework/aop/target/dynamic/AbstractRefreshableTargetSource.java
index 7bab7e07711..75d698db9d8 100644
--- a/spring-aop/src/main/java/org/springframework/aop/target/dynamic/AbstractRefreshableTargetSource.java
+++ b/spring-aop/src/main/java/org/springframework/aop/target/dynamic/AbstractRefreshableTargetSource.java
@@ -20,6 +20,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.aop.TargetSource;
+import org.springframework.lang.Nullable;
 
 /**
  * Abstract {@link org.springframework.aop.TargetSource} implementation that
@@ -41,6 +42,7 @@ public abstract class AbstractRefreshableTargetSource implements TargetSource, R
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	protected Object targetObject;
 
 	private long refreshCheckDelay = -1;
@@ -80,6 +82,7 @@ public abstract class AbstractRefreshableTargetSource implements TargetSource, R
 	}
 
 	@Override
+	@Nullable
 	public final synchronized Object getTarget() {
 		if ((refreshCheckDelayElapsed() && requiresRefresh()) || this.targetObject == null) {
 			refresh();
diff --git a/spring-aop/src/main/java/org/springframework/aop/target/package.html b/spring-aop/src/main/java/org/springframework/aop/target/package.html
deleted file mode 100644
index 26f9d79a879..00000000000
--- a/spring-aop/src/main/java/org/springframework/aop/target/package.html
+++ /dev/null
@@ -1,15 +0,0 @@
-<html>
-<body>
-
-This package contains implementations of the org.springframework.aop.TargetSource interface.
-<br>
-The simplest implementation is the SingletonTargetSource, used by default in the AOP framework
-to wrap a single target instance. This is normally appropriate.
-
-<br>
-Other provided implementations include pooling implementations, that provide a target
-from a pool for each request, ensuring a single threaded programming model; and a 
-"prototype" implementation, that uses a new target instance for each invocation.
-
-</body>
-</html>
diff --git a/spring-beans/src/main/java/org/springframework/beans/AbstractNestablePropertyAccessor.java b/spring-beans/src/main/java/org/springframework/beans/AbstractNestablePropertyAccessor.java
index 5ab67b7558e..bf960b1ba67 100644
--- a/spring-beans/src/main/java/org/springframework/beans/AbstractNestablePropertyAccessor.java
+++ b/spring-beans/src/main/java/org/springframework/beans/AbstractNestablePropertyAccessor.java
@@ -483,6 +483,7 @@ public abstract class AbstractNestablePropertyAccessor extends AbstractPropertyA
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getPropertyType(String propertyName) throws BeansException {
 		try {
 			PropertyHandler ph = getPropertyHandler(propertyName);
@@ -510,6 +511,7 @@ public abstract class AbstractNestablePropertyAccessor extends AbstractPropertyA
 	}
 
 	@Override
+	@Nullable
 	public TypeDescriptor getPropertyTypeDescriptor(String propertyName) throws BeansException {
 		try {
 			AbstractNestablePropertyAccessor nestedPa = getPropertyAccessorForPropertyPath(propertyName);
@@ -603,6 +605,7 @@ public abstract class AbstractNestablePropertyAccessor extends AbstractPropertyA
 	}
 
 	@Override
+	@Nullable
 	public Object getPropertyValue(String propertyName) throws BeansException {
 		AbstractNestablePropertyAccessor nestedPa = getPropertyAccessorForPropertyPath(propertyName);
 		PropertyTokenHolder tokens = getPropertyNameTokens(getFinalPath(nestedPa, propertyName));
diff --git a/spring-beans/src/main/java/org/springframework/beans/AbstractPropertyAccessor.java b/spring-beans/src/main/java/org/springframework/beans/AbstractPropertyAccessor.java
index eb551fbd663..34310708f7f 100644
--- a/spring-beans/src/main/java/org/springframework/beans/AbstractPropertyAccessor.java
+++ b/spring-beans/src/main/java/org/springframework/beans/AbstractPropertyAccessor.java
@@ -127,6 +127,7 @@ public abstract class AbstractPropertyAccessor extends TypeConverterSupport impl
 
 	// Redefined with public visibility.
 	@Override
+	@Nullable
 	public Class<?> getPropertyType(String propertyPath) {
 		return null;
 	}
@@ -141,6 +142,7 @@ public abstract class AbstractPropertyAccessor extends TypeConverterSupport impl
 	 * accessor method failed
 	 */
 	@Override
+	@Nullable
 	public abstract Object getPropertyValue(String propertyName) throws BeansException;
 
 	/**
diff --git a/spring-beans/src/main/java/org/springframework/beans/BeanMetadataAttributeAccessor.java b/spring-beans/src/main/java/org/springframework/beans/BeanMetadataAttributeAccessor.java
index 644655902a5..d68c5769b5d 100644
--- a/spring-beans/src/main/java/org/springframework/beans/BeanMetadataAttributeAccessor.java
+++ b/spring-beans/src/main/java/org/springframework/beans/BeanMetadataAttributeAccessor.java
@@ -74,12 +74,14 @@ public class BeanMetadataAttributeAccessor extends AttributeAccessorSupport impl
 	}
 
 	@Override
+	@Nullable
 	public Object getAttribute(String name) {
 		BeanMetadataAttribute attribute = (BeanMetadataAttribute) super.getAttribute(name);
 		return (attribute != null ? attribute.getValue() : null);
 	}
 
 	@Override
+	@Nullable
 	public Object removeAttribute(String name) {
 		BeanMetadataAttribute attribute = (BeanMetadataAttribute) super.removeAttribute(name);
 		return (attribute != null ? attribute.getValue() : null);
diff --git a/spring-beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java b/spring-beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java
index aaff2e63c51..3225a458f4b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java
+++ b/spring-beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java
@@ -225,6 +225,7 @@ public class BeanWrapperImpl extends AbstractNestablePropertyAccessor implements
 	}
 
 	@Override
+	@Nullable
 	protected BeanPropertyHandler getLocalPropertyHandler(String propertyName) {
 		PropertyDescriptor pd = getCachedIntrospectionResults().getPropertyDescriptor(propertyName);
 		if (pd != null) {
@@ -284,11 +285,13 @@ public class BeanWrapperImpl extends AbstractNestablePropertyAccessor implements
 		}
 
 		@Override
+		@Nullable
 		public TypeDescriptor nested(int level) {
 			return TypeDescriptor.nested(property(pd), level);
 		}
 
 		@Override
+		@Nullable
 		public Object getValue() throws Exception {
 			final Method readMethod = this.pd.getReadMethod();
 			if (System.getSecurityManager() != null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/DirectFieldAccessor.java b/spring-beans/src/main/java/org/springframework/beans/DirectFieldAccessor.java
index 912f32e0775..bffe0eec2d1 100644
--- a/spring-beans/src/main/java/org/springframework/beans/DirectFieldAccessor.java
+++ b/spring-beans/src/main/java/org/springframework/beans/DirectFieldAccessor.java
@@ -117,11 +117,13 @@ public class DirectFieldAccessor extends AbstractNestablePropertyAccessor {
 		}
 
 		@Override
+		@Nullable
 		public TypeDescriptor nested(int level) {
 			return TypeDescriptor.nested(this.field, level);
 		}
 
 		@Override
+		@Nullable
 		public Object getValue() throws Exception {
 			try {
 				ReflectionUtils.makeAccessible(this.field);
diff --git a/spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfoFactory.java b/spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfoFactory.java
index f3759739bf9..c48dbd1890b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfoFactory.java
+++ b/spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfoFactory.java
@@ -22,6 +22,7 @@ import java.beans.Introspector;
 import java.lang.reflect.Method;
 
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link BeanInfoFactory} implementation that evaluates whether bean classes have
@@ -42,6 +43,7 @@ public class ExtendedBeanInfoFactory implements BeanInfoFactory, Ordered {
 	 * Return an {@link ExtendedBeanInfo} for the given bean class, if applicable.
 	 */
 	@Override
+	@Nullable
 	public BeanInfo getBeanInfo(Class<?> beanClass) throws IntrospectionException {
 		return (supports(beanClass) ? new ExtendedBeanInfo(Introspector.getBeanInfo(beanClass)) : null);
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java b/spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java
index af3ff3ad923..49a84cb60aa 100644
--- a/spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java
+++ b/spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.java
@@ -250,6 +250,7 @@ public class MutablePropertyValues implements PropertyValues, Serializable {
 	}
 
 	@Override
+	@Nullable
 	public PropertyValue getPropertyValue(String propertyName) {
 		for (PropertyValue pv : this.propertyValueList) {
 			if (pv.getName().equals(propertyName)) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/TypeConverterSupport.java b/spring-beans/src/main/java/org/springframework/beans/TypeConverterSupport.java
index 9c875389618..809cd61250b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/TypeConverterSupport.java
+++ b/spring-beans/src/main/java/org/springframework/beans/TypeConverterSupport.java
@@ -39,11 +39,13 @@ public abstract class TypeConverterSupport extends PropertyEditorRegistrySupport
 
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType) throws TypeMismatchException {
 		return doConvert(value, requiredType, null, null);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType, @Nullable MethodParameter methodParam)
 			throws TypeMismatchException {
 
@@ -51,6 +53,7 @@ public abstract class TypeConverterSupport extends PropertyEditorRegistrySupport
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType, @Nullable Field field)
 			throws TypeMismatchException {
 
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AnnotationBeanWiringInfoResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AnnotationBeanWiringInfoResolver.java
index 78fe8fe86af..78a690b475f 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AnnotationBeanWiringInfoResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AnnotationBeanWiringInfoResolver.java
@@ -18,6 +18,7 @@ package org.springframework.beans.factory.annotation;
 
 import org.springframework.beans.factory.wiring.BeanWiringInfo;
 import org.springframework.beans.factory.wiring.BeanWiringInfoResolver;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
@@ -37,6 +38,7 @@ import org.springframework.util.ClassUtils;
 public class AnnotationBeanWiringInfoResolver implements BeanWiringInfoResolver {
 
 	@Override
+	@Nullable
 	public BeanWiringInfo resolveWiringInfo(Object beanInstance) {
 		Assert.notNull(beanInstance, "Bean instance must not be null");
 		Configurable annotation = beanInstance.getClass().getAnnotation(Configurable.class);
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessor.java b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessor.java
index 10055b9c500..3c256571354 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessor.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/AutowiredAnnotationBeanPostProcessor.java
@@ -234,6 +234,7 @@ public class AutowiredAnnotationBeanPostProcessor extends InstantiationAwareBean
 	}
 
 	@Override
+	@Nullable
 	public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, final String beanName)
 			throws BeanCreationException {
 
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/QualifierAnnotationAutowireCandidateResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/QualifierAnnotationAutowireCandidateResolver.java
index 35fc98e21ff..19a64242314 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/annotation/QualifierAnnotationAutowireCandidateResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/annotation/QualifierAnnotationAutowireCandidateResolver.java
@@ -330,6 +330,7 @@ public class QualifierAnnotationAutowireCandidateResolver extends GenericTypeAwa
 	 * @see Value
 	 */
 	@Override
+	@Nullable
 	public Object getSuggestedValue(DependencyDescriptor descriptor) {
 		Object value = findValue(descriptor.getAnnotations());
 		if (value == null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/AbstractFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/AbstractFactoryBean.java
index 7f230919cd9..fe1dcf8bdd4 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/AbstractFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/AbstractFactoryBean.java
@@ -206,6 +206,7 @@ public abstract class AbstractFactoryBean<T>
 	 * @see org.springframework.beans.factory.FactoryBean#getObjectType()
 	 */
 	@Override
+	@Nullable
 	public abstract Class<?> getObjectType();
 
 	/**
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java
index 26e02b62af9..8556c3affbf 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/BeanDefinitionHolder.java
@@ -113,6 +113,7 @@ public class BeanDefinitionHolder implements BeanMetadataElement {
 	 * @see BeanDefinition#getSource()
 	 */
 	@Override
+	@Nullable
 	public Object getSource() {
 		return this.beanDefinition.getSource();
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/EmbeddedValueResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/EmbeddedValueResolver.java
index 99925990a9f..c4fb65d55dc 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/EmbeddedValueResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/EmbeddedValueResolver.java
@@ -49,6 +49,7 @@ public class EmbeddedValueResolver implements StringValueResolver {
 
 
 	@Override
+	@Nullable
 	public String resolveStringValue(String strVal) {
 		String value = this.exprContext.getBeanFactory().resolveEmbeddedValue(strVal);
 		if (this.exprResolver != null && value != null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBean.java
index ec6b9dd95cb..c537ee2f85b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/FieldRetrievingFactoryBean.java
@@ -208,6 +208,7 @@ public class FieldRetrievingFactoryBean
 
 
 	@Override
+	@Nullable
 	public Object getObject() throws IllegalAccessException {
 		if (this.fieldObject == null) {
 			throw new FactoryBeanNotInitializedException();
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/InstantiationAwareBeanPostProcessorAdapter.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/InstantiationAwareBeanPostProcessorAdapter.java
index 3f7e1746b70..abe387968c9 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/InstantiationAwareBeanPostProcessorAdapter.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/InstantiationAwareBeanPostProcessorAdapter.java
@@ -21,6 +21,7 @@ import java.lang.reflect.Constructor;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.PropertyValues;
+import org.springframework.lang.Nullable;
 
 /**
  * Adapter that implements all methods on {@link SmartInstantiationAwareBeanPostProcessor}
@@ -40,11 +41,13 @@ import org.springframework.beans.PropertyValues;
 public abstract class InstantiationAwareBeanPostProcessorAdapter implements SmartInstantiationAwareBeanPostProcessor {
 
 	@Override
+	@Nullable
 	public Class<?> predictBeanType(Class<?> beanClass, String beanName) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName) throws BeansException {
 		return null;
 	}
@@ -55,6 +58,7 @@ public abstract class InstantiationAwareBeanPostProcessorAdapter implements Smar
 	}
 
 	@Override
+	@Nullable
 	public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
 		return null;
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/MethodInvokingFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/MethodInvokingFactoryBean.java
index 8091ed3a51e..f3d1243f23a 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/MethodInvokingFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/MethodInvokingFactoryBean.java
@@ -116,6 +116,7 @@ public class MethodInvokingFactoryBean extends MethodInvokingBean implements Fac
 	 * specified method on the fly.
 	 */
 	@Override
+	@Nullable
 	public Object getObject() throws Exception {
 		if (this.singleton) {
 			if (!this.initialized) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertiesFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertiesFactoryBean.java
index 17fbc9c4edf..444ca98ba93 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertiesFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertiesFactoryBean.java
@@ -75,6 +75,7 @@ public class PropertiesFactoryBean extends PropertiesLoaderSupport
 	}
 
 	@Override
+	@Nullable
 	public final Properties getObject() throws IOException {
 		if (this.singleton) {
 			return this.singletonInstance;
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPathFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPathFactoryBean.java
index 0e903911f02..c9a8d42cedd 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPathFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPathFactoryBean.java
@@ -201,6 +201,7 @@ public class PropertyPathFactoryBean implements FactoryBean<Object>, BeanNameAwa
 
 
 	@Override
+	@Nullable
 	public Object getObject() throws BeansException {
 		BeanWrapper target = this.targetBeanWrapper;
 		if (target != null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.java
index 6aa5551fd24..34fe7ec5f5b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.java
@@ -239,6 +239,7 @@ public class PropertyPlaceholderConfigurer extends PlaceholderConfigurerSupport
 		}
 
 		@Override
+		@Nullable
 		public String resolveStringValue(String strVal) throws BeansException {
 			String resolved = this.helper.replacePlaceholders(strVal, this.resolver);
 			if (trimValues) {
@@ -258,6 +259,7 @@ public class PropertyPlaceholderConfigurer extends PlaceholderConfigurerSupport
 		}
 
 		@Override
+		@Nullable
 		public String resolvePlaceholder(String placeholderName) {
 			return PropertyPlaceholderConfigurer.this.resolvePlaceholder(placeholderName, props, systemPropertiesMode);
 		}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/ServiceLocatorFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/ServiceLocatorFactoryBean.java
index 24707690420..d507556fbf4 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/ServiceLocatorFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/ServiceLocatorFactoryBean.java
@@ -329,6 +329,7 @@ public class ServiceLocatorFactoryBean implements FactoryBean<Object>, BeanFacto
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.proxy;
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlMapFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlMapFactoryBean.java
index 38e846a4d98..d8f6e41a996 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlMapFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlMapFactoryBean.java
@@ -97,6 +97,7 @@ public class YamlMapFactoryBean extends YamlProcessor implements FactoryBean<Map
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getObject() {
 		return (this.map != null ? this.map : createMap());
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlPropertiesFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlPropertiesFactoryBean.java
index c4dc698b07e..dec79025063 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlPropertiesFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/config/YamlPropertiesFactoryBean.java
@@ -108,6 +108,7 @@ public class YamlPropertiesFactoryBean extends YamlProcessor implements FactoryB
 	}
 
 	@Override
+	@Nullable
 	public Properties getObject() {
 		return (this.properties != null ? this.properties : createProperties());
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/ServiceFactoryBean.java b/spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/ServiceFactoryBean.java
index c337ba19b46..3c546e96759 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/ServiceFactoryBean.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/ServiceFactoryBean.java
@@ -20,6 +20,7 @@ import java.util.Iterator;
 import java.util.ServiceLoader;
 
 import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link org.springframework.beans.factory.FactoryBean} that exposes the
@@ -43,6 +44,7 @@ public class ServiceFactoryBean extends AbstractServiceLoaderBasedFactoryBean im
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getObjectType() {
 		return getServiceType();
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java
index cb5403f6f1d..40270cb502f 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java
@@ -340,6 +340,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	}
 
 	@Override
+	@Nullable
 	public Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName) throws BeansException {
 		return resolveDependency(descriptor, requestingBeanName, null, null);
 	}
@@ -409,11 +410,13 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	}
 
 	@Override
+	@Nullable
 	public Object initializeBean(Object existingBean, String beanName) {
 		return initializeBean(beanName, existingBean, null);
 	}
 
 	@Override
+	@Nullable
 	public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName)
 			throws BeansException {
 
@@ -428,6 +431,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	}
 
 	@Override
+	@Nullable
 	public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
 			throws BeansException {
 
@@ -457,6 +461,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 * @see #doCreateBean
 	 */
 	@Override
+	@Nullable
 	protected Object createBean(String beanName, RootBeanDefinition mbd, @Nullable Object[] args)
 			throws BeanCreationException {
 
@@ -634,6 +639,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	}
 
 	@Override
+	@Nullable
 	protected Class<?> predictBeanType(String beanName, RootBeanDefinition mbd, Class<?>... typesToMatch) {
 		Class<?> targetType = determineTargetType(beanName, mbd, typesToMatch);
 
@@ -800,6 +806,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 * it will be fully created to check the type of its exposed object.
 	 */
 	@Override
+	@Nullable
 	protected Class<?> getTypeForFactoryBean(String beanName, RootBeanDefinition mbd) {
 		String factoryBeanName = mbd.getFactoryBeanName();
 		String factoryMethodName = mbd.getFactoryMethodName();
@@ -1177,6 +1184,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	 * @see #obtainFromSupplier
 	 */
 	@Override
+	@Nullable
 	protected Object getObjectForBeanInstance(
 			@Nullable Object beanInstance, String name, String beanName, @Nullable RootBeanDefinition mbd) {
 
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java
index 346b11cb271..581e2673912 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanDefinition.java
@@ -358,6 +358,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	 * Return the current bean class name of this bean definition.
 	 */
 	@Override
+	@Nullable
 	public String getBeanClassName() {
 		Object beanClassObject = this.beanClass;
 		if (beanClassObject instanceof Class) {
@@ -971,6 +972,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	 * came from (for the purpose of showing context in case of errors).
 	 */
 	@Override
+	@Nullable
 	public String getResourceDescription() {
 		return (this.resource != null ? this.resource.getDescription() : null);
 	}
@@ -989,6 +991,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	 * originator chain to find the original BeanDefinition as defined by the user.
 	 */
 	@Override
+	@Nullable
 	public BeanDefinition getOriginatingBeanDefinition() {
 		return (this.resource instanceof BeanDefinitionResource ?
 				((BeanDefinitionResource) this.resource).getBeanDefinition() : null);
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java
index 8118772eb25..a55b541655b 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractBeanFactory.java
@@ -599,6 +599,7 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getType(String name) throws NoSuchBeanDefinitionException {
 		String beanName = transformedBeanName(name);
 
@@ -840,6 +841,7 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	}
 
 	@Override
+	@Nullable
 	public String resolveEmbeddedValue(@Nullable String value) {
 		if (value == null) {
 			return null;
@@ -926,6 +928,7 @@ public abstract class AbstractBeanFactory extends FactoryBeanRegistrySupport imp
 	}
 
 	@Override
+	@Nullable
 	public Scope getRegisteredScope(String scopeName) {
 		Assert.notNull(scopeName, "Scope identifier must not be null");
 		return this.scopes.get(scopeName);
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java
index 6547d004e56..03ff2b76df3 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java
@@ -570,6 +570,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 	 * if not found on the exposed bean reference (e.g. in case of a proxy).
 	 */
 	@Override
+	@Nullable
 	public <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType)
 			throws NoSuchBeanDefinitionException{
 
@@ -1037,6 +1038,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 	}
 
 	@Override
+	@Nullable
 	public Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName,
 			@Nullable Set<String> autowiredBeanNames, @Nullable TypeConverter typeConverter) throws BeansException {
 
@@ -1613,6 +1615,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		}
 
 		@Override
+		@Nullable
 		public Object getObject() throws BeansException {
 			if (this.optional) {
 				return createOptionalDependency(this.descriptor, this.beanName);
@@ -1623,6 +1626,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		}
 
 		@Override
+		@Nullable
 		public Object getObject(final Object... args) throws BeansException {
 			if (this.optional) {
 				return createOptionalDependency(this.descriptor, this.beanName, args);
@@ -1639,6 +1643,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		}
 
 		@Override
+		@Nullable
 		public Object getIfAvailable() throws BeansException {
 			if (this.optional) {
 				return createOptionalDependency(this.descriptor, this.beanName);
@@ -1655,6 +1660,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		}
 
 		@Override
+		@Nullable
 		public Object getIfUnique() throws BeansException {
 			DependencyDescriptor descriptorToUse = new DependencyDescriptor(descriptor) {
 				@Override
@@ -1662,6 +1668,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 					return false;
 				}
 				@Override
+				@Nullable
 				public Object resolveNotUnique(Class<?> type, Map<String, Object> matchingBeans) {
 					return null;
 				}
@@ -1720,6 +1727,7 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 		}
 
 		@Override
+		@Nullable
 		public Object getOrderSource(Object obj) {
 			RootBeanDefinition beanDefinition = getRootBeanDefinition(this.instancesToBeanNames.get(obj));
 			if (beanDefinition == null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java
index 52320a452e7..62a0105e30c 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java
@@ -171,6 +171,7 @@ public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements
 	}
 
 	@Override
+	@Nullable
 	public Object getSingleton(String beanName) {
 		return getSingleton(beanName, true);
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/SimpleAutowireCandidateResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/SimpleAutowireCandidateResolver.java
index ddbf3b4127c..2d4577e81a7 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/SimpleAutowireCandidateResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/SimpleAutowireCandidateResolver.java
@@ -41,11 +41,13 @@ public class SimpleAutowireCandidateResolver implements AutowireCandidateResolve
 	}
 
 	@Override
+	@Nullable
 	public Object getSuggestedValue(DependencyDescriptor descriptor) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public Object getLazyResolutionProxyIfNecessary(DependencyDescriptor descriptor, @Nullable String beanName) {
 		return null;
 	}
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java b/spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java
index d72031c8b08..21a5318445c 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/support/StaticListableBeanFactory.java
@@ -355,6 +355,7 @@ public class StaticListableBeanFactory implements ListableBeanFactory {
 	}
 
 	@Override
+	@Nullable
 	public <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType)
 			throws NoSuchBeanDefinitionException{
 
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/AbstractBeanDefinitionParser.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/AbstractBeanDefinitionParser.java
index aeba4e7741c..2300573a213 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/AbstractBeanDefinitionParser.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/AbstractBeanDefinitionParser.java
@@ -58,6 +58,7 @@ public abstract class AbstractBeanDefinitionParser implements BeanDefinitionPars
 
 
 	@Override
+	@Nullable
 	public final BeanDefinition parse(Element element, ParserContext parserContext) {
 		AbstractBeanDefinition definition = parseInternal(element, parserContext);
 		if (definition != null && !parserContext.isNested()) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/DefaultNamespaceHandlerResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/DefaultNamespaceHandlerResolver.java
index 24744dc7942..cd4a9399af7 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/DefaultNamespaceHandlerResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/DefaultNamespaceHandlerResolver.java
@@ -113,6 +113,7 @@ public class DefaultNamespaceHandlerResolver implements NamespaceHandlerResolver
 	 * @return the located {@link NamespaceHandler}, or {@code null} if none found
 	 */
 	@Override
+	@Nullable
 	public NamespaceHandler resolve(String namespaceUri) {
 		Map<String, Object> handlerMappings = getHandlerMappings();
 		Object handlerOrClassName = handlerMappings.get(namespaceUri);
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/NamespaceHandlerSupport.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/NamespaceHandlerSupport.java
index 4869d095274..5582837fa93 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/NamespaceHandlerSupport.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/NamespaceHandlerSupport.java
@@ -68,6 +68,7 @@ public abstract class NamespaceHandlerSupport implements NamespaceHandler {
 	 * registered for that {@link Element}.
 	 */
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		BeanDefinitionParser parser = findParserForElement(element, parserContext);
 		return (parser != null ? parser.parse(element, parserContext) : null);
@@ -93,6 +94,7 @@ public abstract class NamespaceHandlerSupport implements NamespaceHandler {
 	 * is registered to handle that {@link Node}.
 	 */
 	@Override
+	@Nullable
 	public BeanDefinitionHolder decorate(
 			Node node, BeanDefinitionHolder definition, ParserContext parserContext) {
 
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/ResourceEntityResolver.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/ResourceEntityResolver.java
index 2882ac7ce3a..53d9e807caa 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/ResourceEntityResolver.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/ResourceEntityResolver.java
@@ -71,6 +71,7 @@ public class ResourceEntityResolver extends DelegatingEntityResolver {
 
 
 	@Override
+	@Nullable
 	public InputSource resolveEntity(String publicId, @Nullable String systemId) throws SAXException, IOException {
 		InputSource source = super.resolveEntity(publicId, systemId);
 		if (source == null && systemId != null) {
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimpleConstructorNamespaceHandler.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimpleConstructorNamespaceHandler.java
index 3f305146984..da1f062dbee 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimpleConstructorNamespaceHandler.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimpleConstructorNamespaceHandler.java
@@ -28,6 +28,7 @@ import org.springframework.beans.factory.config.ConstructorArgumentValues;
 import org.springframework.beans.factory.config.ConstructorArgumentValues.ValueHolder;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.core.Conventions;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -68,6 +69,7 @@ public class SimpleConstructorNamespaceHandler implements NamespaceHandler {
 	}
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		parserContext.getReaderContext().error(
 				"Class [" + getClass().getName() + "] does not support custom elements.", element);
diff --git a/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimplePropertyNamespaceHandler.java b/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimplePropertyNamespaceHandler.java
index e6716d2900b..7a1e1604da1 100644
--- a/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimplePropertyNamespaceHandler.java
+++ b/spring-beans/src/main/java/org/springframework/beans/factory/xml/SimplePropertyNamespaceHandler.java
@@ -25,6 +25,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinitionHolder;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.core.Conventions;
+import org.springframework.lang.Nullable;
 
 /**
  * Simple {@code NamespaceHandler} implementation that maps custom attributes
@@ -57,6 +58,7 @@ public class SimplePropertyNamespaceHandler implements NamespaceHandler {
 	}
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		parserContext.getReaderContext().error(
 				"Class [" + getClass().getName() + "] does not support custom elements.", element);
diff --git a/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCache.java b/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCache.java
index f7be4ea94ed..fa673b87422 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCache.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCache.java
@@ -83,6 +83,7 @@ public class CaffeineCache extends AbstractValueAdaptingCache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper get(Object key) {
 		if (this.cache instanceof LoadingCache) {
 			Object value = ((LoadingCache<Object, Object>) this.cache).get(key);
diff --git a/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java b/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java
index a886df6b091..bf0ec1ff4cc 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java
@@ -176,6 +176,7 @@ public class CaffeineCacheManager implements CacheManager {
 	}
 
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		Cache cache = this.cacheMap.get(name);
 		if (cache == null && this.dynamic) {
diff --git a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheCache.java b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheCache.java
index 2bcc663a9b6..38b3bd193b7 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheCache.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheCache.java
@@ -64,6 +64,7 @@ public class EhCacheCache implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper get(Object key) {
 		Element element = lookup(key);
 		return toValueWrapper(element);
@@ -125,6 +126,7 @@ public class EhCacheCache implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper putIfAbsent(Object key, @Nullable Object value) {
 		Element existingElement = this.cache.putIfAbsent(new Element(key, value));
 		return toValueWrapper(existingElement);
diff --git a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheFactoryBean.java b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheFactoryBean.java
index a18910b6447..1622741711c 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheFactoryBean.java
@@ -287,6 +287,7 @@ public class EhCacheFactoryBean extends CacheConfiguration implements FactoryBea
 
 
 	@Override
+	@Nullable
 	public Ehcache getObject() {
 		return this.cache;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheManagerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheManagerFactoryBean.java
index bc760edfdb4..4e41ae91a46 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheManagerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/ehcache/EhCacheManagerFactoryBean.java
@@ -169,6 +169,7 @@ public class EhCacheManagerFactoryBean implements FactoryBean<CacheManager>, Ini
 
 
 	@Override
+	@Nullable
 	public CacheManager getObject() {
 		return this.cacheManager;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheCache.java b/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheCache.java
index 4269afb8252..7dfea6c3ab2 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheCache.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheCache.java
@@ -76,6 +76,7 @@ public class JCacheCache extends AbstractValueAdaptingCache {
 	}
 
 	@Override
+	@Nullable
 	public <T> T get(Object key, Callable<T> valueLoader) {
 		try {
 			return this.cache.invoke(key, new ValueLoaderEntryProcessor<T>(), valueLoader);
@@ -91,6 +92,7 @@ public class JCacheCache extends AbstractValueAdaptingCache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper putIfAbsent(Object key, @Nullable Object value) {
 		boolean set = this.cache.putIfAbsent(key, toStoreValue(value));
 		return (set ? null : get(key));
diff --git a/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheManagerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheManagerFactoryBean.java
index 8408d218779..50938bf20eb 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheManagerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/jcache/JCacheManagerFactoryBean.java
@@ -85,6 +85,7 @@ public class JCacheManagerFactoryBean
 
 
 	@Override
+	@Nullable
 	public CacheManager getObject() {
 		return this.cacheManager;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheDecorator.java b/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheDecorator.java
index 1f00abbf39f..bd4da577efb 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheDecorator.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheDecorator.java
@@ -72,6 +72,7 @@ public class TransactionAwareCacheDecorator implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper get(Object key) {
 		return this.targetCache.get(key);
 	}
@@ -82,6 +83,7 @@ public class TransactionAwareCacheDecorator implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public <T> T get(Object key, Callable<T> valueLoader) {
 		return this.targetCache.get(key, valueLoader);
 	}
@@ -102,6 +104,7 @@ public class TransactionAwareCacheDecorator implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper putIfAbsent(Object key, @Nullable Object value) {
 		return this.targetCache.putIfAbsent(key, value);
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheManagerProxy.java b/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheManagerProxy.java
index e56f69d282f..f20f894ea25 100644
--- a/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheManagerProxy.java
+++ b/spring-context-support/src/main/java/org/springframework/cache/transaction/TransactionAwareCacheManagerProxy.java
@@ -76,6 +76,7 @@ public class TransactionAwareCacheManagerProxy implements CacheManager, Initiali
 
 
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		Assert.state(this.targetCacheManager != null, "No target CacheManager set");
 		Cache targetCache = this.targetCacheManager.getCache(name);
diff --git a/spring-context-support/src/main/java/org/springframework/mail/MailSendException.java b/spring-context-support/src/main/java/org/springframework/mail/MailSendException.java
index 5b7fd6e050a..b0c66d26877 100644
--- a/spring-context-support/src/main/java/org/springframework/mail/MailSendException.java
+++ b/spring-context-support/src/main/java/org/springframework/mail/MailSendException.java
@@ -123,6 +123,7 @@ public class MailSendException extends MailException {
 
 
 	@Override
+	@Nullable
 	public String getMessage() {
 		if (ObjectUtils.isEmpty(this.messageExceptions)) {
 			return super.getMessage();
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerFactoryBean.java
index a1fe4568e39..0e63817e3c7 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerFactoryBean.java
@@ -110,6 +110,7 @@ public class TimerManagerFactoryBean extends TimerManagerAccessor
 	//---------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public TimerManager getObject() {
 		return getTimerManager();
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerTaskScheduler.java b/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerTaskScheduler.java
index aabe2226a50..b77a5073fba 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerTaskScheduler.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/commonj/TimerManagerTaskScheduler.java
@@ -56,6 +56,7 @@ public class TimerManagerTaskScheduler extends TimerManagerAccessor implements T
 
 
 	@Override
+	@Nullable
 	public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
 		return new ReschedulingTimerListener(errorHandlingTask(task, true), trigger).schedule();
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/CronTriggerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/CronTriggerFactoryBean.java
index 41ddc931601..ae5cee80076 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/CronTriggerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/CronTriggerFactoryBean.java
@@ -266,6 +266,7 @@ public class CronTriggerFactoryBean implements FactoryBean<CronTrigger>, BeanNam
 
 
 	@Override
+	@Nullable
 	public CronTrigger getObject() {
 		return this.cronTrigger;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/JobDetailFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/JobDetailFactoryBean.java
index 01c79210549..7cc703bdf15 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/JobDetailFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/JobDetailFactoryBean.java
@@ -218,6 +218,7 @@ public class JobDetailFactoryBean
 
 
 	@Override
+	@Nullable
 	public JobDetail getObject() {
 		return this.jobDetail;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/MethodInvokingJobDetailFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/MethodInvokingJobDetailFactoryBean.java
index de36084c922..33992a60321 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/MethodInvokingJobDetailFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/MethodInvokingJobDetailFactoryBean.java
@@ -223,6 +223,7 @@ public class MethodInvokingJobDetailFactoryBean extends ArgumentConvertingMethod
 
 
 	@Override
+	@Nullable
 	public JobDetail getObject() {
 		return this.jobDetail;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerFactoryBean.java
index 35307d5f725..e4923e042d0 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerFactoryBean.java
@@ -708,6 +708,7 @@ public class SchedulerFactoryBean extends SchedulerAccessor implements FactoryBe
 	}
 
 	@Override
+	@Nullable
 	public Scheduler getObject() {
 		return this.scheduler;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SimpleTriggerFactoryBean.java b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SimpleTriggerFactoryBean.java
index c5e6e17e193..8d010bbdd0f 100644
--- a/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SimpleTriggerFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/scheduling/quartz/SimpleTriggerFactoryBean.java
@@ -251,6 +251,7 @@ public class SimpleTriggerFactoryBean implements FactoryBean<SimpleTrigger>, Bea
 
 
 	@Override
+	@Nullable
 	public SimpleTrigger getObject() {
 		return this.simpleTrigger;
 	}
diff --git a/spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactoryBean.java b/spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactoryBean.java
index b9d90101bd6..3f4841ca83a 100644
--- a/spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactoryBean.java
+++ b/spring-context-support/src/main/java/org/springframework/ui/freemarker/FreeMarkerConfigurationFactoryBean.java
@@ -65,6 +65,7 @@ public class FreeMarkerConfigurationFactoryBean extends FreeMarkerConfigurationF
 
 
 	@Override
+	@Nullable
 	public Configuration getObject() {
 		return this.configuration;
 	}
diff --git a/spring-context/src/main/java/org/springframework/cache/Cache.java b/spring-context/src/main/java/org/springframework/cache/Cache.java
index a4b97d3e3f5..37f814181ef 100644
--- a/spring-context/src/main/java/org/springframework/cache/Cache.java
+++ b/spring-context/src/main/java/org/springframework/cache/Cache.java
@@ -157,7 +157,8 @@ public interface Cache {
 		/**
 		 * Return the actual value in the cache.
 		 */
-		@Nullable Object get();
+		@Nullable
+		Object get();
 	}
 
 
diff --git a/spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java b/spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java
index c6fdeaa2afa..0c805052557 100644
--- a/spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java
+++ b/spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java
@@ -106,11 +106,13 @@ public class AnnotationCacheOperationSource extends AbstractFallbackCacheOperati
 
 
 	@Override
+	@Nullable
 	protected Collection<CacheOperation> findCacheOperations(final Class<?> clazz) {
 		return determineCacheOperations(parser -> parser.parseCacheAnnotations(clazz));
 	}
 
 	@Override
+	@Nullable
 	protected Collection<CacheOperation> findCacheOperations(final Method method) {
 		return determineCacheOperations(parser -> parser.parseCacheAnnotations(method));
 	}
diff --git a/spring-context/src/main/java/org/springframework/cache/annotation/CachingConfigurerSupport.java b/spring-context/src/main/java/org/springframework/cache/annotation/CachingConfigurerSupport.java
index de53ffa5850..6719efa137a 100644
--- a/spring-context/src/main/java/org/springframework/cache/annotation/CachingConfigurerSupport.java
+++ b/spring-context/src/main/java/org/springframework/cache/annotation/CachingConfigurerSupport.java
@@ -20,6 +20,7 @@ import org.springframework.cache.CacheManager;
 import org.springframework.cache.interceptor.CacheErrorHandler;
 import org.springframework.cache.interceptor.CacheResolver;
 import org.springframework.cache.interceptor.KeyGenerator;
+import org.springframework.lang.Nullable;
 
 /**
  * An implementation of {@link CachingConfigurer} with empty methods allowing
@@ -32,21 +33,25 @@ import org.springframework.cache.interceptor.KeyGenerator;
 public class CachingConfigurerSupport implements CachingConfigurer {
 
 	@Override
+	@Nullable
 	public CacheManager cacheManager() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public KeyGenerator keyGenerator() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public CacheResolver cacheResolver() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public CacheErrorHandler errorHandler() {
 		return null;
 	}
diff --git a/spring-context/src/main/java/org/springframework/cache/annotation/SpringCacheAnnotationParser.java b/spring-context/src/main/java/org/springframework/cache/annotation/SpringCacheAnnotationParser.java
index 3134029bd61..17874bba4e5 100644
--- a/spring-context/src/main/java/org/springframework/cache/annotation/SpringCacheAnnotationParser.java
+++ b/spring-context/src/main/java/org/springframework/cache/annotation/SpringCacheAnnotationParser.java
@@ -48,12 +48,14 @@ import org.springframework.util.StringUtils;
 public class SpringCacheAnnotationParser implements CacheAnnotationParser, Serializable {
 
 	@Override
+	@Nullable
 	public Collection<CacheOperation> parseCacheAnnotations(Class<?> type) {
 		DefaultCacheConfig defaultConfig = getDefaultCacheConfig(type);
 		return parseCacheAnnotations(defaultConfig, type);
 	}
 
 	@Override
+	@Nullable
 	public Collection<CacheOperation> parseCacheAnnotations(Method method) {
 		DefaultCacheConfig defaultConfig = getDefaultCacheConfig(method.getDeclaringClass());
 		return parseCacheAnnotations(defaultConfig, method);
diff --git a/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheFactoryBean.java b/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheFactoryBean.java
index 1ec7322b663..9b64a041e8e 100644
--- a/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheFactoryBean.java
@@ -92,6 +92,7 @@ public class ConcurrentMapCacheFactoryBean
 
 
 	@Override
+	@Nullable
 	public ConcurrentMapCache getObject() {
 		return this.cache;
 	}
diff --git a/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheManager.java b/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheManager.java
index 7958bc8c24e..217ea350956 100644
--- a/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheManager.java
+++ b/spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheManager.java
@@ -162,6 +162,7 @@ public class ConcurrentMapCacheManager implements CacheManager, BeanClassLoaderA
 	}
 
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		Cache cache = this.cacheMap.get(name);
 		if (cache == null && this.dynamic) {
diff --git a/spring-context/src/main/java/org/springframework/cache/config/AnnotationDrivenCacheBeanDefinitionParser.java b/spring-context/src/main/java/org/springframework/cache/config/AnnotationDrivenCacheBeanDefinitionParser.java
index 26ff1e8021a..a0d3c10200c 100644
--- a/spring-context/src/main/java/org/springframework/cache/config/AnnotationDrivenCacheBeanDefinitionParser.java
+++ b/spring-context/src/main/java/org/springframework/cache/config/AnnotationDrivenCacheBeanDefinitionParser.java
@@ -75,6 +75,7 @@ class AnnotationDrivenCacheBeanDefinitionParser implements BeanDefinitionParser
 	 * register an AutoProxyCreator} with the container as necessary.
 	 */
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		String mode = element.getAttribute("mode");
 		if ("aspectj".equals(mode)) {
diff --git a/spring-context/src/main/java/org/springframework/cache/interceptor/AbstractFallbackCacheOperationSource.java b/spring-context/src/main/java/org/springframework/cache/interceptor/AbstractFallbackCacheOperationSource.java
index db4788c67d4..9cd38014786 100644
--- a/spring-context/src/main/java/org/springframework/cache/interceptor/AbstractFallbackCacheOperationSource.java
+++ b/spring-context/src/main/java/org/springframework/cache/interceptor/AbstractFallbackCacheOperationSource.java
@@ -83,6 +83,7 @@ public abstract class AbstractFallbackCacheOperationSource implements CacheOpera
 	 * is not cacheable
 	 */
 	@Override
+	@Nullable
 	public Collection<CacheOperation> getCacheOperations(Method method, @Nullable Class<?> targetClass) {
 		if (method.getDeclaringClass() == Object.class) {
 			return null;
diff --git a/spring-context/src/main/java/org/springframework/cache/interceptor/BeanFactoryCacheOperationSourceAdvisor.java b/spring-context/src/main/java/org/springframework/cache/interceptor/BeanFactoryCacheOperationSourceAdvisor.java
index 929bc667e2c..9375095c1c5 100644
--- a/spring-context/src/main/java/org/springframework/cache/interceptor/BeanFactoryCacheOperationSourceAdvisor.java
+++ b/spring-context/src/main/java/org/springframework/cache/interceptor/BeanFactoryCacheOperationSourceAdvisor.java
@@ -36,6 +36,7 @@ public class BeanFactoryCacheOperationSourceAdvisor extends AbstractBeanFactoryP
 
 	private final CacheOperationSourcePointcut pointcut = new CacheOperationSourcePointcut() {
 		@Override
+		@Nullable
 		protected CacheOperationSource getCacheOperationSource() {
 			return cacheOperationSource;
 		}
diff --git a/spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContext.java b/spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContext.java
index 7e3ad6078c7..985c55befc0 100644
--- a/spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContext.java
+++ b/spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContext.java
@@ -22,6 +22,7 @@ import java.util.Set;
 
 import org.springframework.context.expression.MethodBasedEvaluationContext;
 import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.lang.Nullable;
 
 /**
  * Cache specific evaluation context that adds a method parameters as SpEL
@@ -69,6 +70,7 @@ class CacheEvaluationContext extends MethodBasedEvaluationContext {
 	 * Load the param information only when needed.
 	 */
 	@Override
+	@Nullable
 	public Object lookupVariable(String name) {
 		if (this.unavailableVariables.contains(name)) {
 			throw new VariableNotAvailableException(name);
diff --git a/spring-context/src/main/java/org/springframework/cache/interceptor/CompositeCacheOperationSource.java b/spring-context/src/main/java/org/springframework/cache/interceptor/CompositeCacheOperationSource.java
index a4fe20c588a..a5baa2cc43e 100644
--- a/spring-context/src/main/java/org/springframework/cache/interceptor/CompositeCacheOperationSource.java
+++ b/spring-context/src/main/java/org/springframework/cache/interceptor/CompositeCacheOperationSource.java
@@ -55,6 +55,7 @@ public class CompositeCacheOperationSource implements CacheOperationSource, Seri
 	}
 
 	@Override
+	@Nullable
 	public Collection<CacheOperation> getCacheOperations(Method method, @Nullable Class<?> targetClass) {
 		Collection<CacheOperation> ops = null;
 
diff --git a/spring-context/src/main/java/org/springframework/cache/interceptor/NameMatchCacheOperationSource.java b/spring-context/src/main/java/org/springframework/cache/interceptor/NameMatchCacheOperationSource.java
index 71b2b173617..515261b9d71 100644
--- a/spring-context/src/main/java/org/springframework/cache/interceptor/NameMatchCacheOperationSource.java
+++ b/spring-context/src/main/java/org/springframework/cache/interceptor/NameMatchCacheOperationSource.java
@@ -75,6 +75,7 @@ public class NameMatchCacheOperationSource implements CacheOperationSource, Seri
 	}
 
 	@Override
+	@Nullable
 	public Collection<CacheOperation> getCacheOperations(Method method, @Nullable Class<?> targetClass) {
 		// look for direct name match
 		String methodName = method.getName();
diff --git a/spring-context/src/main/java/org/springframework/cache/support/AbstractCacheManager.java b/spring-context/src/main/java/org/springframework/cache/support/AbstractCacheManager.java
index 7acb7deb1b2..18ddddb39c8 100644
--- a/spring-context/src/main/java/org/springframework/cache/support/AbstractCacheManager.java
+++ b/spring-context/src/main/java/org/springframework/cache/support/AbstractCacheManager.java
@@ -85,6 +85,7 @@ public abstract class AbstractCacheManager implements CacheManager, Initializing
 	// Lazy cache initialization on access
 
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		Cache cache = this.cacheMap.get(name);
 		if (cache != null) {
diff --git a/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java b/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java
index f10ec707bf8..0d250b83960 100644
--- a/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java
+++ b/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java
@@ -27,6 +27,7 @@ import java.util.Set;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.cache.Cache;
 import org.springframework.cache.CacheManager;
+import org.springframework.lang.Nullable;
 
 /**
  * Composite {@link CacheManager} implementation that iterates over
@@ -98,6 +99,7 @@ public class CompositeCacheManager implements CacheManager, InitializingBean {
 
 
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		for (CacheManager cacheManager : this.cacheManagers) {
 			Cache cache = cacheManager.getCache(name);
diff --git a/spring-context/src/main/java/org/springframework/cache/support/NoOpCache.java b/spring-context/src/main/java/org/springframework/cache/support/NoOpCache.java
index df16dbbc84d..144f69f8e94 100644
--- a/spring-context/src/main/java/org/springframework/cache/support/NoOpCache.java
+++ b/spring-context/src/main/java/org/springframework/cache/support/NoOpCache.java
@@ -58,16 +58,19 @@ public class NoOpCache implements Cache {
 	}
 
 	@Override
+	@Nullable
 	public ValueWrapper get(Object key) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public <T> T get(Object key, @Nullable Class<T> type) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public <T> T get(Object key, Callable<T> valueLoader) {
 		try {
 			return valueLoader.call();
diff --git a/spring-context/src/main/java/org/springframework/cache/support/NoOpCacheManager.java b/spring-context/src/main/java/org/springframework/cache/support/NoOpCacheManager.java
index ce8176ff22e..d6ba68b99f6 100644
--- a/spring-context/src/main/java/org/springframework/cache/support/NoOpCacheManager.java
+++ b/spring-context/src/main/java/org/springframework/cache/support/NoOpCacheManager.java
@@ -25,6 +25,7 @@ import java.util.concurrent.ConcurrentMap;
 
 import org.springframework.cache.Cache;
 import org.springframework.cache.CacheManager;
+import org.springframework.lang.Nullable;
 
 /**
  * A basic, no operation {@link CacheManager} implementation suitable
@@ -50,6 +51,7 @@ public class NoOpCacheManager implements CacheManager {
 	 * Additionally, the request cache will be remembered by the manager for consistency.
 	 */
 	@Override
+	@Nullable
 	public Cache getCache(String name) {
 		Cache cache = this.caches.get(name);
 		if (cache == null) {
diff --git a/spring-context/src/main/java/org/springframework/cache/support/SimpleValueWrapper.java b/spring-context/src/main/java/org/springframework/cache/support/SimpleValueWrapper.java
index 4524dd39350..d44c19a7486 100644
--- a/spring-context/src/main/java/org/springframework/cache/support/SimpleValueWrapper.java
+++ b/spring-context/src/main/java/org/springframework/cache/support/SimpleValueWrapper.java
@@ -45,6 +45,7 @@ public class SimpleValueWrapper implements ValueWrapper {
 	 * Simply returns the value as given at construction time.
 	 */
 	@Override
+	@Nullable
 	public Object get() {
 		return this.value;
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigBeanDefinitionParser.java b/spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigBeanDefinitionParser.java
index de52f2e6d32..24402a48de8 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigBeanDefinitionParser.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigBeanDefinitionParser.java
@@ -26,6 +26,7 @@ import org.springframework.beans.factory.parsing.BeanComponentDefinition;
 import org.springframework.beans.factory.parsing.CompositeComponentDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 
 /**
  * Parser for the &lt;context:annotation-config/&gt; element.
@@ -39,6 +40,7 @@ import org.springframework.beans.factory.xml.ParserContext;
 public class AnnotationConfigBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);
 
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java b/spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java
index aefd00d5beb..085eebdb0d5 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ClassPathBeanDefinitionScanner.java
@@ -173,6 +173,7 @@ public class ClassPathBeanDefinitionScanner extends ClassPathScanningCandidateCo
 	/**
 	 * Return the BeanDefinitionRegistry that this scanner operates on.
 	 */
+	@Override
 	public final BeanDefinitionRegistry getRegistry() {
 		return this.registry;
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java b/spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java
index 4b056d0032c..6b5958eeb8f 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java
@@ -79,6 +79,7 @@ public class ComponentScanBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		String basePackage = element.getAttribute(BASE_PACKAGE_ATTRIBUTE);
 		basePackage = parserContext.getReaderContext().getEnvironment().resolvePlaceholders(basePackage);
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
index a8ed2ad816c..6d72e89e3ce 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
@@ -714,6 +714,7 @@ class ConfigurationClassParser {
 		}
 
 		@Override
+		@Nullable
 		public AnnotationMetadata getImportingClassFor(String importedClass) {
 			List<AnnotationMetadata> list = this.imports.get(importedClass);
 			return (!CollectionUtils.isEmpty(list) ? list.get(list.size() - 1) : null);
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java b/spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java
index ea899bb70ac..6e2ba609a6e 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java
@@ -47,6 +47,7 @@ import org.springframework.util.Assert;
 public class ContextAnnotationAutowireCandidateResolver extends QualifierAnnotationAutowireCandidateResolver {
 
 	@Override
+	@Nullable
 	public Object getLazyResolutionProxyIfNecessary(DependencyDescriptor descriptor, @Nullable String beanName) {
 		return (isLazy(descriptor) ? buildLazyResolutionProxy(descriptor, beanName) : null);
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ScannedGenericBeanDefinition.java b/spring-context/src/main/java/org/springframework/context/annotation/ScannedGenericBeanDefinition.java
index 1b815588459..6a8129702f8 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ScannedGenericBeanDefinition.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ScannedGenericBeanDefinition.java
@@ -22,6 +22,7 @@ import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.MethodMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -68,6 +69,7 @@ public class ScannedGenericBeanDefinition extends GenericBeanDefinition implemen
 	}
 
 	@Override
+	@Nullable
 	public MethodMetadata getFactoryMethodMetadata() {
 		return null;
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/expression/MethodBasedEvaluationContext.java b/spring-context/src/main/java/org/springframework/context/expression/MethodBasedEvaluationContext.java
index 32f904f5f31..a20446fd9cb 100644
--- a/spring-context/src/main/java/org/springframework/context/expression/MethodBasedEvaluationContext.java
+++ b/spring-context/src/main/java/org/springframework/context/expression/MethodBasedEvaluationContext.java
@@ -21,6 +21,7 @@ import java.util.Arrays;
 
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -60,6 +61,7 @@ public class MethodBasedEvaluationContext extends StandardEvaluationContext {
 
 
 	@Override
+	@Nullable
 	public Object lookupVariable(String name) {
 		Object variable = super.lookupVariable(name);
 		if (variable != null) {
diff --git a/spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java b/spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java
index 28a4c8db665..c1767e8baff 100644
--- a/spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java
+++ b/spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java
@@ -132,6 +132,7 @@ public class StandardBeanExpressionResolver implements BeanExpressionResolver {
 
 
 	@Override
+	@Nullable
 	public Object evaluate(@Nullable String value, BeanExpressionContext evalContext) throws BeansException {
 		if (!StringUtils.hasLength(value)) {
 			return value;
diff --git a/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java b/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java
index 76e05a5b45c..276ac7cec5b 100644
--- a/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java
+++ b/spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java
@@ -1137,6 +1137,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getType(String name) throws NoSuchBeanDefinitionException {
 		assertBeanFactoryActive();
 		return getBeanFactory().getType(name);
@@ -1214,6 +1215,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	}
 
 	@Override
+	@Nullable
 	public <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType)
 			throws NoSuchBeanDefinitionException{
 
@@ -1227,6 +1229,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	//---------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public BeanFactory getParentBeanFactory() {
 		return getParent();
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/support/ApplicationContextAwareProcessor.java b/spring-context/src/main/java/org/springframework/context/support/ApplicationContextAwareProcessor.java
index ef071f4b335..c5843342b4e 100644
--- a/spring-context/src/main/java/org/springframework/context/support/ApplicationContextAwareProcessor.java
+++ b/spring-context/src/main/java/org/springframework/context/support/ApplicationContextAwareProcessor.java
@@ -31,6 +31,7 @@ import org.springframework.context.EmbeddedValueResolverAware;
 import org.springframework.context.EnvironmentAware;
 import org.springframework.context.MessageSourceAware;
 import org.springframework.context.ResourceLoaderAware;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringValueResolver;
 
 /**
@@ -74,6 +75,7 @@ class ApplicationContextAwareProcessor implements BeanPostProcessor {
 
 
 	@Override
+	@Nullable
 	public Object postProcessBeforeInitialization(final Object bean, String beanName) throws BeansException {
 		AccessControlContext acc = null;
 
diff --git a/spring-context/src/main/java/org/springframework/context/support/ConversionServiceFactoryBean.java b/spring-context/src/main/java/org/springframework/context/support/ConversionServiceFactoryBean.java
index 4991136b058..f7234203086 100644
--- a/spring-context/src/main/java/org/springframework/context/support/ConversionServiceFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/context/support/ConversionServiceFactoryBean.java
@@ -87,6 +87,7 @@ public class ConversionServiceFactoryBean implements FactoryBean<ConversionServi
 	// implementing FactoryBean
 
 	@Override
+	@Nullable
 	public ConversionService getObject() {
 		return this.conversionService;
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/support/GenericApplicationContext.java b/spring-context/src/main/java/org/springframework/context/support/GenericApplicationContext.java
index f094c231b58..0314b69b722 100644
--- a/spring-context/src/main/java/org/springframework/context/support/GenericApplicationContext.java
+++ b/spring-context/src/main/java/org/springframework/context/support/GenericApplicationContext.java
@@ -245,6 +245,7 @@ public class GenericApplicationContext extends AbstractApplicationContext implem
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getClassLoader() {
 		if (this.resourceLoader != null && !this.customClassLoader) {
 			return this.resourceLoader.getClassLoader();
diff --git a/spring-context/src/main/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurer.java b/spring-context/src/main/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurer.java
index dd6affb72b2..032a0ed5eeb 100644
--- a/spring-context/src/main/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurer.java
+++ b/spring-context/src/main/java/org/springframework/context/support/PropertySourcesPlaceholderConfigurer.java
@@ -132,6 +132,7 @@ public class PropertySourcesPlaceholderConfigurer extends PlaceholderConfigurerS
 				this.propertySources.addLast(
 					new PropertySource<Environment>(ENVIRONMENT_PROPERTIES_PROPERTY_SOURCE_NAME, this.environment) {
 						@Override
+						@Nullable
 						public String getProperty(String key) {
 							return this.source.getProperty(key);
 						}
diff --git a/spring-context/src/main/java/org/springframework/context/support/ReloadableResourceBundleMessageSource.java b/spring-context/src/main/java/org/springframework/context/support/ReloadableResourceBundleMessageSource.java
index e5f5f1a6c0c..1f7f50b2b14 100644
--- a/spring-context/src/main/java/org/springframework/context/support/ReloadableResourceBundleMessageSource.java
+++ b/spring-context/src/main/java/org/springframework/context/support/ReloadableResourceBundleMessageSource.java
@@ -201,6 +201,7 @@ public class ReloadableResourceBundleMessageSource extends AbstractResourceBased
 	 * using a cached MessageFormat instance per message code.
 	 */
 	@Override
+	@Nullable
 	protected MessageFormat resolveCode(String code, Locale locale) {
 		if (getCacheMillis() < 0) {
 			PropertiesHolder propHolder = getMergedProperties(locale);
diff --git a/spring-context/src/main/java/org/springframework/context/support/ResourceBundleMessageSource.java b/spring-context/src/main/java/org/springframework/context/support/ResourceBundleMessageSource.java
index 93f1a68c371..15395a9fd8c 100644
--- a/spring-context/src/main/java/org/springframework/context/support/ResourceBundleMessageSource.java
+++ b/spring-context/src/main/java/org/springframework/context/support/ResourceBundleMessageSource.java
@@ -145,6 +145,7 @@ public class ResourceBundleMessageSource extends AbstractResourceBasedMessageSou
 	 * using a cached MessageFormat instance per message code.
 	 */
 	@Override
+	@Nullable
 	protected MessageFormat resolveCode(String code, Locale locale) {
 		Set<String> basenames = getBasenameSet();
 		for (String basename : basenames) {
diff --git a/spring-context/src/main/java/org/springframework/context/support/SimpleThreadScope.java b/spring-context/src/main/java/org/springframework/context/support/SimpleThreadScope.java
index c0caf4d572b..6101de2a100 100644
--- a/spring-context/src/main/java/org/springframework/context/support/SimpleThreadScope.java
+++ b/spring-context/src/main/java/org/springframework/context/support/SimpleThreadScope.java
@@ -25,6 +25,7 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.config.Scope;
 import org.springframework.core.NamedThreadLocal;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -78,6 +79,7 @@ public class SimpleThreadScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		Map<String, Object> scope = this.threadScope.get();
 		return scope.remove(name);
@@ -90,6 +92,7 @@ public class SimpleThreadScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveContextualObject(String key) {
 		return null;
 	}
diff --git a/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java b/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
index 9efe2b141f6..ec336dd1407 100644
--- a/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
+++ b/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
@@ -21,6 +21,7 @@ import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -47,6 +48,7 @@ public class StaticMessageSource extends AbstractMessageSource {
 	}
 
 	@Override
+	@Nullable
 	protected MessageFormat resolveCode(String code, Locale locale) {
 		String key = code + '_' + locale.toString();
 		String msg = this.messages.get(key);
diff --git a/spring-context/src/main/java/org/springframework/ejb/access/AbstractRemoteSlsbInvokerInterceptor.java b/spring-context/src/main/java/org/springframework/ejb/access/AbstractRemoteSlsbInvokerInterceptor.java
index 4170852332a..8b752d09434 100644
--- a/spring-context/src/main/java/org/springframework/ejb/access/AbstractRemoteSlsbInvokerInterceptor.java
+++ b/spring-context/src/main/java/org/springframework/ejb/access/AbstractRemoteSlsbInvokerInterceptor.java
@@ -95,6 +95,7 @@ public abstract class AbstractRemoteSlsbInvokerInterceptor extends AbstractSlsbI
 	 * @see #refreshAndRetry
 	 */
 	@Override
+	@Nullable
 	public Object invokeInContext(MethodInvocation invocation) throws Throwable {
 		try {
 			return doInvoke(invocation);
diff --git a/spring-context/src/main/java/org/springframework/ejb/access/LocalSlsbInvokerInterceptor.java b/spring-context/src/main/java/org/springframework/ejb/access/LocalSlsbInvokerInterceptor.java
index d54621eb9a7..ece921cadfb 100644
--- a/spring-context/src/main/java/org/springframework/ejb/access/LocalSlsbInvokerInterceptor.java
+++ b/spring-context/src/main/java/org/springframework/ejb/access/LocalSlsbInvokerInterceptor.java
@@ -62,6 +62,7 @@ public class LocalSlsbInvokerInterceptor extends AbstractSlsbInvokerInterceptor
 	 * for example to hold a single shared EJB instance.
 	 */
 	@Override
+	@Nullable
 	public Object invokeInContext(MethodInvocation invocation) throws Throwable {
 		Object ejb = null;
 		try {
diff --git a/spring-context/src/main/java/org/springframework/ejb/access/LocalStatelessSessionProxyFactoryBean.java b/spring-context/src/main/java/org/springframework/ejb/access/LocalStatelessSessionProxyFactoryBean.java
index b0edf884ddf..9d73b7fb444 100644
--- a/spring-context/src/main/java/org/springframework/ejb/access/LocalStatelessSessionProxyFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/ejb/access/LocalStatelessSessionProxyFactoryBean.java
@@ -98,6 +98,7 @@ public class LocalStatelessSessionProxyFactoryBean extends LocalSlsbInvokerInter
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.proxy;
 	}
diff --git a/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteSlsbInvokerInterceptor.java b/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteSlsbInvokerInterceptor.java
index bf7aa03b14b..56681ddcdbc 100644
--- a/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteSlsbInvokerInterceptor.java
+++ b/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteSlsbInvokerInterceptor.java
@@ -93,6 +93,7 @@ public class SimpleRemoteSlsbInvokerInterceptor extends AbstractRemoteSlsbInvoke
 	 * for example to hold a single shared EJB component instance.
 	 */
 	@Override
+	@Nullable
 	protected Object doInvoke(MethodInvocation invocation) throws Throwable {
 		Object ejb = null;
 		try {
diff --git a/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteStatelessSessionProxyFactoryBean.java b/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteStatelessSessionProxyFactoryBean.java
index fd32d9de807..7d9f5221265 100644
--- a/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteStatelessSessionProxyFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/ejb/access/SimpleRemoteStatelessSessionProxyFactoryBean.java
@@ -112,6 +112,7 @@ public class SimpleRemoteStatelessSessionProxyFactoryBean extends SimpleRemoteSl
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.proxy;
 	}
diff --git a/spring-context/src/main/java/org/springframework/format/datetime/joda/DateTimeFormatterFactoryBean.java b/spring-context/src/main/java/org/springframework/format/datetime/joda/DateTimeFormatterFactoryBean.java
index 08b43009034..a5ef98c8352 100644
--- a/spring-context/src/main/java/org/springframework/format/datetime/joda/DateTimeFormatterFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/format/datetime/joda/DateTimeFormatterFactoryBean.java
@@ -47,6 +47,7 @@ public class DateTimeFormatterFactoryBean extends DateTimeFormatterFactory
 	}
 
 	@Override
+	@Nullable
 	public DateTimeFormatter getObject() {
 		return this.dateTimeFormatter;
 	}
diff --git a/spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeFormatterFactoryBean.java b/spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeFormatterFactoryBean.java
index 4c805ab1dc1..ef999079e27 100644
--- a/spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeFormatterFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeFormatterFactoryBean.java
@@ -47,6 +47,7 @@ public class DateTimeFormatterFactoryBean extends DateTimeFormatterFactory
 	}
 
 	@Override
+	@Nullable
 	public DateTimeFormatter getObject() {
 		return this.dateTimeFormatter;
 	}
diff --git a/spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java b/spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java
index 8cf286a2a44..6136727225e 100644
--- a/spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java
+++ b/spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java
@@ -189,6 +189,7 @@ public class FormattingConversionService extends GenericConversionService
 		}
 
 		@Override
+		@Nullable
 		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			String text = (String) source;
 			if (!StringUtils.hasText(text)) {
@@ -247,6 +248,7 @@ public class FormattingConversionService extends GenericConversionService
 
 		@Override
 		@SuppressWarnings("unchecked")
+		@Nullable
 		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			Annotation ann = sourceType.getAnnotation(this.annotationType);
 			if (ann == null) {
@@ -301,6 +303,7 @@ public class FormattingConversionService extends GenericConversionService
 
 		@Override
 		@SuppressWarnings("unchecked")
+		@Nullable
 		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			Annotation ann = targetType.getAnnotation(this.annotationType);
 			if (ann == null) {
diff --git a/spring-context/src/main/java/org/springframework/format/support/FormattingConversionServiceFactoryBean.java b/spring-context/src/main/java/org/springframework/format/support/FormattingConversionServiceFactoryBean.java
index 491a7bf8394..4a9c130fbbd 100644
--- a/spring-context/src/main/java/org/springframework/format/support/FormattingConversionServiceFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/format/support/FormattingConversionServiceFactoryBean.java
@@ -167,6 +167,7 @@ public class FormattingConversionServiceFactoryBean
 
 
 	@Override
+	@Nullable
 	public FormattingConversionService getObject() {
 		return this.conversionService;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jmx/access/MBeanProxyFactoryBean.java b/spring-context/src/main/java/org/springframework/jmx/access/MBeanProxyFactoryBean.java
index d2c4f96d8f3..1f5c0a2e660 100644
--- a/spring-context/src/main/java/org/springframework/jmx/access/MBeanProxyFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jmx/access/MBeanProxyFactoryBean.java
@@ -99,6 +99,7 @@ public class MBeanProxyFactoryBean extends MBeanClientInterceptor
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.mbeanProxy;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java b/spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java
index 97d567b416d..a5825c8fa0e 100644
--- a/spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java
+++ b/spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java
@@ -1102,6 +1102,7 @@ public class MBeanExporter extends MBeanRegistrationSupport implements MBeanExpo
 		}
 
 		@Override
+		@Nullable
 		public Object getTarget() {
 			try {
 				return super.getTarget();
diff --git a/spring-context/src/main/java/org/springframework/jmx/export/annotation/AnnotationJmxAttributeSource.java b/spring-context/src/main/java/org/springframework/jmx/export/annotation/AnnotationJmxAttributeSource.java
index 7beb0eb02ef..7036d867c17 100644
--- a/spring-context/src/main/java/org/springframework/jmx/export/annotation/AnnotationJmxAttributeSource.java
+++ b/spring-context/src/main/java/org/springframework/jmx/export/annotation/AnnotationJmxAttributeSource.java
@@ -63,6 +63,7 @@ public class AnnotationJmxAttributeSource implements JmxAttributeSource, BeanFac
 
 
 	@Override
+	@Nullable
 	public org.springframework.jmx.export.metadata.ManagedResource getManagedResource(Class<?> beanClass) throws InvalidMetadataException {
 		ManagedResource ann = AnnotationUtils.findAnnotation(beanClass, ManagedResource.class);
 		if (ann == null) {
@@ -79,6 +80,7 @@ public class AnnotationJmxAttributeSource implements JmxAttributeSource, BeanFac
 	}
 
 	@Override
+	@Nullable
 	public org.springframework.jmx.export.metadata.ManagedAttribute getManagedAttribute(Method method) throws InvalidMetadataException {
 		ManagedAttribute ann = AnnotationUtils.findAnnotation(method, ManagedAttribute.class);
 		if (ann == null) {
@@ -93,12 +95,14 @@ public class AnnotationJmxAttributeSource implements JmxAttributeSource, BeanFac
 	}
 
 	@Override
+	@Nullable
 	public org.springframework.jmx.export.metadata.ManagedMetric getManagedMetric(Method method) throws InvalidMetadataException {
 		ManagedMetric ann = AnnotationUtils.findAnnotation(method, ManagedMetric.class);
 		return copyPropertiesToBean(ann, org.springframework.jmx.export.metadata.ManagedMetric.class);
 	}
 
 	@Override
+	@Nullable
 	public org.springframework.jmx.export.metadata.ManagedOperation getManagedOperation(Method method) throws InvalidMetadataException {
 		ManagedOperation ann = AnnotationUtils.findAnnotation(method, ManagedOperation.class);
 		return copyPropertiesToBean(ann, org.springframework.jmx.export.metadata.ManagedOperation.class);
diff --git a/spring-context/src/main/java/org/springframework/jmx/support/ConnectorServerFactoryBean.java b/spring-context/src/main/java/org/springframework/jmx/support/ConnectorServerFactoryBean.java
index f26d0ec2d58..9dc4f17a6b4 100644
--- a/spring-context/src/main/java/org/springframework/jmx/support/ConnectorServerFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jmx/support/ConnectorServerFactoryBean.java
@@ -205,6 +205,7 @@ public class ConnectorServerFactoryBean extends MBeanRegistrationSupport
 
 
 	@Override
+	@Nullable
 	public JMXConnectorServer getObject() {
 		return this.connectorServer;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerConnectionFactoryBean.java b/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerConnectionFactoryBean.java
index 034085d639b..274bf0dd9db 100644
--- a/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerConnectionFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerConnectionFactoryBean.java
@@ -157,6 +157,7 @@ public class MBeanServerConnectionFactoryBean
 
 
 	@Override
+	@Nullable
 	public MBeanServerConnection getObject() {
 		return this.connection;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerFactoryBean.java b/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerFactoryBean.java
index b262da33db3..b366214f911 100644
--- a/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jmx/support/MBeanServerFactoryBean.java
@@ -185,6 +185,7 @@ public class MBeanServerFactoryBean implements FactoryBean<MBeanServer>, Initial
 
 
 	@Override
+	@Nullable
 	public MBeanServer getObject() {
 		return this.server;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jmx/support/WebSphereMBeanServerFactoryBean.java b/spring-context/src/main/java/org/springframework/jmx/support/WebSphereMBeanServerFactoryBean.java
index 200bee62bcf..8d22bb87bea 100644
--- a/spring-context/src/main/java/org/springframework/jmx/support/WebSphereMBeanServerFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jmx/support/WebSphereMBeanServerFactoryBean.java
@@ -84,6 +84,7 @@ public class WebSphereMBeanServerFactoryBean implements FactoryBean<MBeanServer>
 
 
 	@Override
+	@Nullable
 	public MBeanServer getObject() {
 		return this.mbeanServer;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jndi/JndiObjectFactoryBean.java b/spring-context/src/main/java/org/springframework/jndi/JndiObjectFactoryBean.java
index 4ce061a6ba9..10c9688b059 100644
--- a/spring-context/src/main/java/org/springframework/jndi/JndiObjectFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/jndi/JndiObjectFactoryBean.java
@@ -266,6 +266,7 @@ public class JndiObjectFactoryBean extends JndiObjectLocator
 	 * Return the singleton JNDI object.
 	 */
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.jndiObject;
 	}
diff --git a/spring-context/src/main/java/org/springframework/jndi/JndiObjectTargetSource.java b/spring-context/src/main/java/org/springframework/jndi/JndiObjectTargetSource.java
index 146306c5e52..c5b24106e68 100644
--- a/spring-context/src/main/java/org/springframework/jndi/JndiObjectTargetSource.java
+++ b/spring-context/src/main/java/org/springframework/jndi/JndiObjectTargetSource.java
@@ -109,6 +109,7 @@ public class JndiObjectTargetSource extends JndiObjectLocator implements TargetS
 
 
 	@Override
+	@Nullable
 	public Class<?> getTargetClass() {
 		if (this.cachedObject != null) {
 			return this.cachedObject.getClass();
@@ -127,6 +128,7 @@ public class JndiObjectTargetSource extends JndiObjectLocator implements TargetS
 	}
 
 	@Override
+	@Nullable
 	public Object getTarget() {
 		try {
 			if (this.lookupOnStartup || !this.cache) {
diff --git a/spring-context/src/main/java/org/springframework/jndi/JndiPropertySource.java b/spring-context/src/main/java/org/springframework/jndi/JndiPropertySource.java
index e2c40f34a89..a55d369226c 100644
--- a/spring-context/src/main/java/org/springframework/jndi/JndiPropertySource.java
+++ b/spring-context/src/main/java/org/springframework/jndi/JndiPropertySource.java
@@ -19,6 +19,7 @@ package org.springframework.jndi;
 import javax.naming.NamingException;
 
 import org.springframework.core.env.PropertySource;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link PropertySource} implementation that reads properties from an underlying Spring
@@ -77,6 +78,7 @@ public class JndiPropertySource extends PropertySource<JndiLocatorDelegate> {
 	 * {@code null} and issues a DEBUG-level log statement with the exception message.
 	 */
 	@Override
+	@Nullable
 	public Object getProperty(String name) {
 		if (getSource().isResourceRef() && name.indexOf(':') != -1) {
 			// We're in resource-ref (prefixing with "java:comp/env") mode. Let's not bother
diff --git a/spring-context/src/main/java/org/springframework/jndi/support/SimpleJndiBeanFactory.java b/spring-context/src/main/java/org/springframework/jndi/support/SimpleJndiBeanFactory.java
index 61fd29d5a3d..42927b64bf4 100644
--- a/spring-context/src/main/java/org/springframework/jndi/support/SimpleJndiBeanFactory.java
+++ b/spring-context/src/main/java/org/springframework/jndi/support/SimpleJndiBeanFactory.java
@@ -187,6 +187,7 @@ public class SimpleJndiBeanFactory extends JndiLocatorSupport implements BeanFac
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getType(String name) throws NoSuchBeanDefinitionException {
 		try {
 			return doGetType(name);
diff --git a/spring-context/src/main/java/org/springframework/remoting/rmi/RmiInvocationWrapper.java b/spring-context/src/main/java/org/springframework/remoting/rmi/RmiInvocationWrapper.java
index df766c67cee..d93ea62ad46 100644
--- a/spring-context/src/main/java/org/springframework/remoting/rmi/RmiInvocationWrapper.java
+++ b/spring-context/src/main/java/org/springframework/remoting/rmi/RmiInvocationWrapper.java
@@ -19,6 +19,7 @@ package org.springframework.remoting.rmi;
 import java.lang.reflect.InvocationTargetException;
 import java.rmi.RemoteException;
 
+import org.springframework.lang.Nullable;
 import org.springframework.remoting.support.RemoteInvocation;
 import org.springframework.util.Assert;
 
@@ -58,6 +59,7 @@ class RmiInvocationWrapper implements RmiInvocationHandler {
 	 * @see RmiBasedExporter#getServiceInterface()
 	 */
 	@Override
+	@Nullable
 	public String getTargetInterfaceName() {
 		Class<?> ifc = this.rmiExporter.getServiceInterface();
 		return (ifc != null ? ifc.getName() : null);
@@ -68,6 +70,7 @@ class RmiInvocationWrapper implements RmiInvocationHandler {
 	 * @see RmiBasedExporter#invoke(org.springframework.remoting.support.RemoteInvocation, Object)
 	 */
 	@Override
+	@Nullable
 	public Object invoke(RemoteInvocation invocation)
 		throws RemoteException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
 
diff --git a/spring-context/src/main/java/org/springframework/scheduling/annotation/AnnotationAsyncExecutionInterceptor.java b/spring-context/src/main/java/org/springframework/scheduling/annotation/AnnotationAsyncExecutionInterceptor.java
index dce1c0182a3..e5700a0d4d2 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/annotation/AnnotationAsyncExecutionInterceptor.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/annotation/AnnotationAsyncExecutionInterceptor.java
@@ -76,6 +76,7 @@ public class AnnotationAsyncExecutionInterceptor extends AsyncExecutionIntercept
 	 * @see #determineAsyncExecutor(Method)
 	 */
 	@Override
+	@Nullable
 	protected String getExecutorQualifier(Method method) {
 		// Maintainer's note: changes made here should also be made in
 		// AnnotationAsyncExecutionAspect#getExecutorQualifier
diff --git a/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurationSelector.java b/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurationSelector.java
index e509f4e7c2d..1263db9ae67 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurationSelector.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurationSelector.java
@@ -18,6 +18,7 @@ package org.springframework.scheduling.annotation;
 
 import org.springframework.context.annotation.AdviceMode;
 import org.springframework.context.annotation.AdviceModeImportSelector;
+import org.springframework.lang.Nullable;
 
 /**
  * Selects which implementation of {@link AbstractAsyncConfiguration} should be used based
@@ -39,6 +40,7 @@ public class AsyncConfigurationSelector extends AdviceModeImportSelector<EnableA
 	 * {@code PROXY} and {@code ASPECTJ} values of {@link EnableAsync#mode()}, respectively
 	 */
 	@Override
+	@Nullable
 	public String[] selectImports(AdviceMode adviceMode) {
 		switch (adviceMode) {
 			case PROXY:
diff --git a/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurerSupport.java b/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurerSupport.java
index 429269f1459..106940fd100 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurerSupport.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncConfigurerSupport.java
@@ -19,6 +19,7 @@ package org.springframework.scheduling.annotation;
 import java.util.concurrent.Executor;
 
 import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
+import org.springframework.lang.Nullable;
 
 /**
  * A convenience {@link AsyncConfigurer} that implements all methods
@@ -36,6 +37,7 @@ public class AsyncConfigurerSupport implements AsyncConfigurer {
 	}
 
 	@Override
+	@Nullable
 	public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
 		return null;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
index 1c9c55c5420..d7ef1698d98 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java
@@ -169,6 +169,7 @@ public class ConcurrentTaskScheduler extends ConcurrentTaskExecutor implements T
 
 
 	@Override
+	@Nullable
 	public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
 		try {
 			if (this.enterpriseConcurrentScheduler) {
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ForkJoinPoolFactoryBean.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ForkJoinPoolFactoryBean.java
index 4801edbbea1..0c6501189a9 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ForkJoinPoolFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ForkJoinPoolFactoryBean.java
@@ -134,6 +134,7 @@ public class ForkJoinPoolFactoryBean implements FactoryBean<ForkJoinPool>, Initi
 
 
 	@Override
+	@Nullable
 	public ForkJoinPool getObject() {
 		return this.forkJoinPool;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ScheduledExecutorFactoryBean.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ScheduledExecutorFactoryBean.java
index 3bc04692041..15c83502b8d 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ScheduledExecutorFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ScheduledExecutorFactoryBean.java
@@ -232,6 +232,7 @@ public class ScheduledExecutorFactoryBean extends ExecutorConfigurationSupport
 
 
 	@Override
+	@Nullable
 	public ScheduledExecutorService getObject() {
 		return this.exposedExecutor;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBean.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBean.java
index 561e3e7e213..d637f374f25 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolExecutorFactoryBean.java
@@ -192,6 +192,7 @@ public class ThreadPoolExecutorFactoryBean extends ExecutorConfigurationSupport
 
 
 	@Override
+	@Nullable
 	public ExecutorService getObject() {
 		return this.exposedExecutor;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
index 2c098b27615..aeb6a973481 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java
@@ -284,6 +284,7 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 	// TaskScheduler implementation
 
 	@Override
+	@Nullable
 	public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
 		ScheduledExecutorService executor = getScheduledExecutor();
 		try {
diff --git a/spring-context/src/main/java/org/springframework/scheduling/config/AnnotationDrivenBeanDefinitionParser.java b/spring-context/src/main/java/org/springframework/scheduling/config/AnnotationDrivenBeanDefinitionParser.java
index f70b84066ee..197a379e68b 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/config/AnnotationDrivenBeanDefinitionParser.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/config/AnnotationDrivenBeanDefinitionParser.java
@@ -27,6 +27,7 @@ import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -46,6 +47,7 @@ public class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParse
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);
 
diff --git a/spring-context/src/main/java/org/springframework/scheduling/config/TaskExecutorFactoryBean.java b/spring-context/src/main/java/org/springframework/scheduling/config/TaskExecutorFactoryBean.java
index 9a9420ce6c2..921600db52e 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/config/TaskExecutorFactoryBean.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/config/TaskExecutorFactoryBean.java
@@ -144,6 +144,7 @@ public class TaskExecutorFactoryBean implements
 
 
 	@Override
+	@Nullable
 	public TaskExecutor getObject() {
 		return this.target;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scheduling/support/SimpleTriggerContext.java b/spring-context/src/main/java/org/springframework/scheduling/support/SimpleTriggerContext.java
index afad1f594f9..e36d0c82b52 100644
--- a/spring-context/src/main/java/org/springframework/scheduling/support/SimpleTriggerContext.java
+++ b/spring-context/src/main/java/org/springframework/scheduling/support/SimpleTriggerContext.java
@@ -72,16 +72,19 @@ public class SimpleTriggerContext implements TriggerContext {
 
 
 	@Override
+	@Nullable
 	public Date lastScheduledExecutionTime() {
 		return this.lastScheduledExecutionTime;
 	}
 
 	@Override
+	@Nullable
 	public Date lastActualExecutionTime() {
 		return this.lastActualExecutionTime;
 	}
 
 	@Override
+	@Nullable
 	public Date lastCompletionTime() {
 		return this.lastCompletionTime;
 	}
diff --git a/spring-context/src/main/java/org/springframework/scripting/bsh/BshScriptFactory.java b/spring-context/src/main/java/org/springframework/scripting/bsh/BshScriptFactory.java
index 074edfa43d6..66bc5c4727d 100644
--- a/spring-context/src/main/java/org/springframework/scripting/bsh/BshScriptFactory.java
+++ b/spring-context/src/main/java/org/springframework/scripting/bsh/BshScriptFactory.java
@@ -122,6 +122,7 @@ public class BshScriptFactory implements ScriptFactory, BeanClassLoaderAware {
 	 * @see BshScriptUtils#createBshObject(String, Class[], ClassLoader)
 	 */
 	@Override
+	@Nullable
 	public Object getScriptedObject(ScriptSource scriptSource, @Nullable Class<?>... actualInterfaces)
 			throws IOException, ScriptCompilationException {
 
@@ -180,6 +181,7 @@ public class BshScriptFactory implements ScriptFactory, BeanClassLoaderAware {
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getScriptedObjectType(ScriptSource scriptSource)
 			throws IOException, ScriptCompilationException {
 
diff --git a/spring-context/src/main/java/org/springframework/scripting/config/ScriptBeanDefinitionParser.java b/spring-context/src/main/java/org/springframework/scripting/config/ScriptBeanDefinitionParser.java
index 1beb649a9b6..e0e906ad931 100644
--- a/spring-context/src/main/java/org/springframework/scripting/config/ScriptBeanDefinitionParser.java
+++ b/spring-context/src/main/java/org/springframework/scripting/config/ScriptBeanDefinitionParser.java
@@ -104,6 +104,7 @@ class ScriptBeanDefinitionParser extends AbstractBeanDefinitionParser {
 	 */
 	@Override
 	@SuppressWarnings("deprecation")
+	@Nullable
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 		// Engine attribute only supported for <lang:std>
 		String engine = element.getAttribute(ENGINE_ATTRIBUTE);
diff --git a/spring-context/src/main/java/org/springframework/scripting/groovy/GroovyScriptFactory.java b/spring-context/src/main/java/org/springframework/scripting/groovy/GroovyScriptFactory.java
index 68b82eddae0..d06d71363b1 100644
--- a/spring-context/src/main/java/org/springframework/scripting/groovy/GroovyScriptFactory.java
+++ b/spring-context/src/main/java/org/springframework/scripting/groovy/GroovyScriptFactory.java
@@ -195,6 +195,7 @@ public class GroovyScriptFactory implements ScriptFactory, BeanFactoryAware, Bea
 	 * @return {@code null} always
 	 */
 	@Override
+	@Nullable
 	public Class<?>[] getScriptInterfaces() {
 		return null;
 	}
@@ -214,6 +215,7 @@ public class GroovyScriptFactory implements ScriptFactory, BeanFactoryAware, Bea
 	 * @see groovy.lang.GroovyClassLoader
 	 */
 	@Override
+	@Nullable
 	public Object getScriptedObject(ScriptSource scriptSource, @Nullable Class<?>... actualInterfaces)
 			throws IOException, ScriptCompilationException {
 
@@ -257,6 +259,7 @@ public class GroovyScriptFactory implements ScriptFactory, BeanFactoryAware, Bea
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getScriptedObjectType(ScriptSource scriptSource)
 			throws IOException, ScriptCompilationException {
 
diff --git a/spring-context/src/main/java/org/springframework/scripting/support/ResourceScriptSource.java b/spring-context/src/main/java/org/springframework/scripting/support/ResourceScriptSource.java
index db8236e3a4b..e6abca378a8 100644
--- a/spring-context/src/main/java/org/springframework/scripting/support/ResourceScriptSource.java
+++ b/spring-context/src/main/java/org/springframework/scripting/support/ResourceScriptSource.java
@@ -128,6 +128,7 @@ public class ResourceScriptSource implements ScriptSource {
 	}
 
 	@Override
+	@Nullable
 	public String suggestedClassName() {
 		String filename = getResource().getFilename();
 		return (filename != null ? StringUtils.stripFilenameExtension(filename) : null);
diff --git a/spring-context/src/main/java/org/springframework/scripting/support/ScriptFactoryPostProcessor.java b/spring-context/src/main/java/org/springframework/scripting/support/ScriptFactoryPostProcessor.java
index 88c22ad6a61..0e379c8ebf6 100644
--- a/spring-context/src/main/java/org/springframework/scripting/support/ScriptFactoryPostProcessor.java
+++ b/spring-context/src/main/java/org/springframework/scripting/support/ScriptFactoryPostProcessor.java
@@ -244,6 +244,7 @@ public class ScriptFactoryPostProcessor extends InstantiationAwareBeanPostProces
 
 
 	@Override
+	@Nullable
 	public Class<?> predictBeanType(Class<?> beanClass, String beanName) {
 		// We only apply special treatment to ScriptFactory implementations here.
 		if (!ScriptFactory.class.isAssignableFrom(beanClass)) {
diff --git a/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptEvaluator.java b/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptEvaluator.java
index e792a1aeb70..112b3400bd3 100644
--- a/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptEvaluator.java
+++ b/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptEvaluator.java
@@ -131,11 +131,13 @@ public class StandardScriptEvaluator implements ScriptEvaluator, BeanClassLoader
 
 
 	@Override
+	@Nullable
 	public Object evaluate(ScriptSource script) {
 		return evaluate(script, null);
 	}
 
 	@Override
+	@Nullable
 	public Object evaluate(ScriptSource script, @Nullable Map<String, Object> argumentBindings) {
 		ScriptEngine engine = getScriptEngine(script);
 		try {
diff --git a/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptFactory.java b/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptFactory.java
index 0c48b931cc0..4c684b35b63 100644
--- a/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptFactory.java
+++ b/spring-context/src/main/java/org/springframework/scripting/support/StandardScriptFactory.java
@@ -139,6 +139,7 @@ public class StandardScriptFactory implements ScriptFactory, BeanClassLoaderAwar
 	 * Load and parse the script via JSR-223's ScriptEngine.
 	 */
 	@Override
+	@Nullable
 	public Object getScriptedObject(ScriptSource scriptSource, @Nullable Class<?>... actualInterfaces)
 			throws IOException, ScriptCompilationException {
 
@@ -259,6 +260,7 @@ public class StandardScriptFactory implements ScriptFactory, BeanClassLoaderAwar
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getScriptedObjectType(ScriptSource scriptSource)
 			throws IOException, ScriptCompilationException {
 
diff --git a/spring-context/src/main/java/org/springframework/scripting/support/StaticScriptSource.java b/spring-context/src/main/java/org/springframework/scripting/support/StaticScriptSource.java
index 839c65aad1f..01f0b72bb37 100644
--- a/spring-context/src/main/java/org/springframework/scripting/support/StaticScriptSource.java
+++ b/spring-context/src/main/java/org/springframework/scripting/support/StaticScriptSource.java
@@ -82,6 +82,7 @@ public class StaticScriptSource implements ScriptSource {
 	}
 
 	@Override
+	@Nullable
 	public String suggestedClassName() {
 		return this.className;
 	}
diff --git a/spring-context/src/main/java/org/springframework/ui/context/support/DelegatingThemeSource.java b/spring-context/src/main/java/org/springframework/ui/context/support/DelegatingThemeSource.java
index a222d11a0ad..7faaac57a5f 100644
--- a/spring-context/src/main/java/org/springframework/ui/context/support/DelegatingThemeSource.java
+++ b/spring-context/src/main/java/org/springframework/ui/context/support/DelegatingThemeSource.java
@@ -51,6 +51,7 @@ public class DelegatingThemeSource implements HierarchicalThemeSource {
 
 
 	@Override
+	@Nullable
 	public Theme getTheme(String themeName) {
 		if (this.parentThemeSource != null) {
 			return this.parentThemeSource.getTheme(themeName);
diff --git a/spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java b/spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java
index 80d1d7cb029..ce47df387b5 100644
--- a/spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java
+++ b/spring-context/src/main/java/org/springframework/ui/context/support/ResourceBundleThemeSource.java
@@ -136,6 +136,7 @@ public class ResourceBundleThemeSource implements HierarchicalThemeSource, BeanC
 	 * @see #createMessageSource
 	 */
 	@Override
+	@Nullable
 	public Theme getTheme(String themeName) {
 		Theme theme = this.themeCache.get(themeName);
 		if (theme == null) {
diff --git a/spring-context/src/main/java/org/springframework/validation/AbstractBindingResult.java b/spring-context/src/main/java/org/springframework/validation/AbstractBindingResult.java
index ec53fbc1f1f..2599919e228 100644
--- a/spring-context/src/main/java/org/springframework/validation/AbstractBindingResult.java
+++ b/spring-context/src/main/java/org/springframework/validation/AbstractBindingResult.java
@@ -168,6 +168,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	}
 
 	@Override
+	@Nullable
 	public ObjectError getGlobalError() {
 		for (ObjectError objectError : this.errors) {
 			if (!(objectError instanceof FieldError)) {
@@ -189,6 +190,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError() {
 		for (ObjectError objectError : this.errors) {
 			if (objectError instanceof FieldError) {
@@ -211,6 +213,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError(String field) {
 		String fixedField = fixedField(field);
 		for (ObjectError objectError : this.errors) {
@@ -225,6 +228,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	}
 
 	@Override
+	@Nullable
 	public Object getFieldValue(String field) {
 		FieldError fieldError = getFieldError(field);
 		// Use rejected value in case of error, current bean property value else.
@@ -244,6 +248,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	 * @see #getActualFieldValue
 	 */
 	@Override
+	@Nullable
 	public Class<?> getFieldType(@Nullable String field) {
 		Object value = getActualFieldValue(fixedField(field));
 		if (value != null) {
@@ -280,6 +285,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	}
 
 	@Override
+	@Nullable
 	public Object getRawFieldValue(String field) {
 		return getActualFieldValue(fixedField(field));
 	}
@@ -290,6 +296,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	 * editor lookup facility, if available.
 	 */
 	@Override
+	@Nullable
 	public PropertyEditor findEditor(@Nullable String field, @Nullable Class<?> valueType) {
 		PropertyEditorRegistry editorRegistry = getPropertyEditorRegistry();
 		if (editorRegistry != null) {
@@ -308,6 +315,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	 * This implementation returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	public PropertyEditorRegistry getPropertyEditorRegistry() {
 		return null;
 	}
@@ -363,6 +371,7 @@ public abstract class AbstractBindingResult extends AbstractErrors implements Bi
 	 * Return the wrapped target object.
 	 */
 	@Override
+	@Nullable
 	public abstract Object getTarget();
 
 	/**
diff --git a/spring-context/src/main/java/org/springframework/validation/AbstractErrors.java b/spring-context/src/main/java/org/springframework/validation/AbstractErrors.java
index be95eb8725e..f432739f02a 100644
--- a/spring-context/src/main/java/org/springframework/validation/AbstractErrors.java
+++ b/spring-context/src/main/java/org/springframework/validation/AbstractErrors.java
@@ -162,6 +162,7 @@ public abstract class AbstractErrors implements Errors, Serializable {
 	}
 
 	@Override
+	@Nullable
 	public ObjectError getGlobalError() {
 		List<ObjectError> globalErrors = getGlobalErrors();
 		return (!globalErrors.isEmpty() ? globalErrors.get(0) : null);
@@ -178,6 +179,7 @@ public abstract class AbstractErrors implements Errors, Serializable {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError() {
 		List<FieldError> fieldErrors = getFieldErrors();
 		return (!fieldErrors.isEmpty() ? fieldErrors.get(0) : null);
@@ -207,13 +209,14 @@ public abstract class AbstractErrors implements Errors, Serializable {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError(String field) {
 		List<FieldError> fieldErrors = getFieldErrors(field);
 		return (!fieldErrors.isEmpty() ? fieldErrors.get(0) : null);
 	}
 
-
 	@Override
+	@Nullable
 	public Class<?> getFieldType(String field) {
 		Object value = getFieldValue(field);
 		return (value != null ? value.getClass() : null);
diff --git a/spring-context/src/main/java/org/springframework/validation/AbstractPropertyBindingResult.java b/spring-context/src/main/java/org/springframework/validation/AbstractPropertyBindingResult.java
index ecedb35fe23..191a68934a0 100644
--- a/spring-context/src/main/java/org/springframework/validation/AbstractPropertyBindingResult.java
+++ b/spring-context/src/main/java/org/springframework/validation/AbstractPropertyBindingResult.java
@@ -88,6 +88,7 @@ public abstract class AbstractPropertyBindingResult extends AbstractBindingResul
 	 * @see #getPropertyAccessor()
 	 */
 	@Override
+	@Nullable
 	public Class<?> getFieldType(@Nullable String field) {
 		return getPropertyAccessor().getPropertyType(fixedField(field));
 	}
@@ -97,6 +98,7 @@ public abstract class AbstractPropertyBindingResult extends AbstractBindingResul
 	 * @see #getPropertyAccessor()
 	 */
 	@Override
+	@Nullable
 	protected Object getActualFieldValue(String field) {
 		return getPropertyAccessor().getPropertyValue(field);
 	}
@@ -150,6 +152,7 @@ public abstract class AbstractPropertyBindingResult extends AbstractBindingResul
 	 * if applicable.
 	 */
 	@Override
+	@Nullable
 	public PropertyEditor findEditor(@Nullable String field, @Nullable Class<?> valueType) {
 		Class<?> valueTypeForLookup = valueType;
 		if (valueTypeForLookup == null) {
diff --git a/spring-context/src/main/java/org/springframework/validation/BindException.java b/spring-context/src/main/java/org/springframework/validation/BindException.java
index 18a5b84bf42..ebf34f3fd14 100644
--- a/spring-context/src/main/java/org/springframework/validation/BindException.java
+++ b/spring-context/src/main/java/org/springframework/validation/BindException.java
@@ -171,6 +171,7 @@ public class BindException extends Exception implements BindingResult {
 	}
 
 	@Override
+	@Nullable
 	public ObjectError getGlobalError() {
 		return this.bindingResult.getGlobalError();
 	}
@@ -191,6 +192,7 @@ public class BindException extends Exception implements BindingResult {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError() {
 		return this.bindingResult.getFieldError();
 	}
@@ -211,16 +213,19 @@ public class BindException extends Exception implements BindingResult {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError(String field) {
 		return this.bindingResult.getFieldError(field);
 	}
 
 	@Override
+	@Nullable
 	public Object getFieldValue(String field) {
 		return this.bindingResult.getFieldValue(field);
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getFieldType(String field) {
 		return this.bindingResult.getFieldType(field);
 	}
@@ -236,6 +241,7 @@ public class BindException extends Exception implements BindingResult {
 	}
 
 	@Override
+	@Nullable
 	public Object getRawFieldValue(String field) {
 		return this.bindingResult.getRawFieldValue(field);
 	}
diff --git a/spring-context/src/main/java/org/springframework/validation/DataBinder.java b/spring-context/src/main/java/org/springframework/validation/DataBinder.java
index 9367f21aa2e..f8fe8df2bc9 100644
--- a/spring-context/src/main/java/org/springframework/validation/DataBinder.java
+++ b/spring-context/src/main/java/org/springframework/validation/DataBinder.java
@@ -672,16 +672,19 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	}
 
 	@Override
+	@Nullable
 	public PropertyEditor findCustomEditor(@Nullable Class<?> requiredType, @Nullable String propertyPath) {
 		return getPropertyEditorRegistry().findCustomEditor(requiredType, propertyPath);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType) throws TypeMismatchException {
 		return getTypeConverter().convertIfNecessary(value, requiredType);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType,
 			@Nullable MethodParameter methodParam) throws TypeMismatchException {
 
@@ -689,6 +692,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType, @Nullable Field field)
 			throws TypeMismatchException {
 
diff --git a/spring-context/src/main/java/org/springframework/validation/MapBindingResult.java b/spring-context/src/main/java/org/springframework/validation/MapBindingResult.java
index 1fc7c5616cb..b2c33732052 100644
--- a/spring-context/src/main/java/org/springframework/validation/MapBindingResult.java
+++ b/spring-context/src/main/java/org/springframework/validation/MapBindingResult.java
@@ -19,6 +19,7 @@ package org.springframework.validation;
 import java.io.Serializable;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -61,6 +62,7 @@ public class MapBindingResult extends AbstractBindingResult implements Serializa
 	}
 
 	@Override
+	@Nullable
 	protected Object getActualFieldValue(String field) {
 		return this.target.get(field);
 	}
diff --git a/spring-context/src/main/java/org/springframework/validation/beanvalidation/SpringValidatorAdapter.java b/spring-context/src/main/java/org/springframework/validation/beanvalidation/SpringValidatorAdapter.java
index 68cb263a141..3483f3f97ec 100644
--- a/spring-context/src/main/java/org/springframework/validation/beanvalidation/SpringValidatorAdapter.java
+++ b/spring-context/src/main/java/org/springframework/validation/beanvalidation/SpringValidatorAdapter.java
@@ -367,6 +367,7 @@ public class SpringValidatorAdapter implements SmartValidator, javax.validation.
 		}
 
 		@Override
+		@Nullable
 		public Object[] getArguments() {
 			return null;
 		}
diff --git a/spring-core/src/main/java/org/springframework/core/AttributeAccessorSupport.java b/spring-core/src/main/java/org/springframework/core/AttributeAccessorSupport.java
index 6b72f9262a3..4595a08ce93 100644
--- a/spring-core/src/main/java/org/springframework/core/AttributeAccessorSupport.java
+++ b/spring-core/src/main/java/org/springframework/core/AttributeAccessorSupport.java
@@ -52,12 +52,14 @@ public abstract class AttributeAccessorSupport implements AttributeAccessor, Ser
 	}
 
 	@Override
+	@Nullable
 	public Object getAttribute(String name) {
 		Assert.notNull(name, "Name must not be null");
 		return this.attributes.get(name);
 	}
 
 	@Override
+	@Nullable
 	public Object removeAttribute(String name) {
 		Assert.notNull(name, "Name must not be null");
 		return this.attributes.remove(name);
diff --git a/spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java b/spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java
index 609567dfa5b..36f5397bd46 100644
--- a/spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java
+++ b/spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java
@@ -282,6 +282,7 @@ public abstract class GenericTypeResolver {
 		}
 
 		@Override
+		@Nullable
 		public ResolvableType resolveVariable(TypeVariable<?> variable) {
 			Type type = this.typeVariableMap.get(variable);
 			return (type != null ? ResolvableType.forType(type) : null);
diff --git a/spring-core/src/main/java/org/springframework/core/LocalVariableTableParameterNameDiscoverer.java b/spring-core/src/main/java/org/springframework/core/LocalVariableTableParameterNameDiscoverer.java
index 1944a342349..1f12d2f2f57 100644
--- a/spring-core/src/main/java/org/springframework/core/LocalVariableTableParameterNameDiscoverer.java
+++ b/spring-core/src/main/java/org/springframework/core/LocalVariableTableParameterNameDiscoverer.java
@@ -65,6 +65,7 @@ public class LocalVariableTableParameterNameDiscoverer implements ParameterNameD
 
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Method method) {
 		Method originalMethod = BridgeMethodResolver.findBridgedMethod(method);
 		Class<?> declaringClass = originalMethod.getDeclaringClass();
@@ -80,6 +81,7 @@ public class LocalVariableTableParameterNameDiscoverer implements ParameterNameD
 	}
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Constructor<?> ctor) {
 		Class<?> declaringClass = ctor.getDeclaringClass();
 		Map<Member, String[]> map = this.parameterNamesCache.get(declaringClass);
diff --git a/spring-core/src/main/java/org/springframework/core/PrioritizedParameterNameDiscoverer.java b/spring-core/src/main/java/org/springframework/core/PrioritizedParameterNameDiscoverer.java
index 0aa80aa9594..9706280ed94 100644
--- a/spring-core/src/main/java/org/springframework/core/PrioritizedParameterNameDiscoverer.java
+++ b/spring-core/src/main/java/org/springframework/core/PrioritizedParameterNameDiscoverer.java
@@ -21,6 +21,8 @@ import java.lang.reflect.Method;
 import java.util.LinkedList;
 import java.util.List;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@link ParameterNameDiscoverer} implementation that tries several discoverer
  * delegates in succession. Those added first in the {@code addDiscoverer} method
@@ -47,6 +49,7 @@ public class PrioritizedParameterNameDiscoverer implements ParameterNameDiscover
 
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Method method) {
 		for (ParameterNameDiscoverer pnd : this.parameterNameDiscoverers) {
 			String[] result = pnd.getParameterNames(method);
@@ -58,6 +61,7 @@ public class PrioritizedParameterNameDiscoverer implements ParameterNameDiscover
 	}
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Constructor<?> ctor) {
 		for (ParameterNameDiscoverer pnd : this.parameterNameDiscoverers) {
 			String[] result = pnd.getParameterNames(ctor);
diff --git a/spring-core/src/main/java/org/springframework/core/ResolvableType.java b/spring-core/src/main/java/org/springframework/core/ResolvableType.java
index f9fabf2c800..66a35ab9830 100644
--- a/spring-core/src/main/java/org/springframework/core/ResolvableType.java
+++ b/spring-core/src/main/java/org/springframework/core/ResolvableType.java
@@ -1419,6 +1419,7 @@ public class ResolvableType implements Serializable {
 	private class DefaultVariableResolver implements VariableResolver {
 
 		@Override
+		@Nullable
 		public ResolvableType resolveVariable(TypeVariable<?> variable) {
 			return ResolvableType.this.resolveVariable(variable);
 		}
@@ -1443,6 +1444,7 @@ public class ResolvableType implements Serializable {
 		}
 
 		@Override
+		@Nullable
 		public ResolvableType resolveVariable(TypeVariable<?> variable) {
 			for (int i = 0; i < this.variables.length; i++) {
 				if (ObjectUtils.nullSafeEquals(SerializableTypeWrapper.unwrap(this.variables[i]),
diff --git a/spring-core/src/main/java/org/springframework/core/SerializableTypeWrapper.java b/spring-core/src/main/java/org/springframework/core/SerializableTypeWrapper.java
index 9cd318b0bbb..272a9c9cbee 100644
--- a/spring-core/src/main/java/org/springframework/core/SerializableTypeWrapper.java
+++ b/spring-core/src/main/java/org/springframework/core/SerializableTypeWrapper.java
@@ -372,6 +372,7 @@ abstract class SerializableTypeWrapper {
 		}
 
 		@Override
+		@Nullable
 		public Type getType() {
 			Object result = this.result;
 			if (result == null) {
@@ -384,6 +385,7 @@ abstract class SerializableTypeWrapper {
 		}
 
 		@Override
+		@Nullable
 		public Object getSource() {
 			return null;
 		}
diff --git a/spring-core/src/main/java/org/springframework/core/StandardReflectionParameterNameDiscoverer.java b/spring-core/src/main/java/org/springframework/core/StandardReflectionParameterNameDiscoverer.java
index 47259fc361a..72e9d859b0a 100644
--- a/spring-core/src/main/java/org/springframework/core/StandardReflectionParameterNameDiscoverer.java
+++ b/spring-core/src/main/java/org/springframework/core/StandardReflectionParameterNameDiscoverer.java
@@ -20,6 +20,8 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@link ParameterNameDiscoverer} implementation which uses JDK 8's reflection facilities
  * for introspecting parameter names (based on the "-parameters" compiler flag).
@@ -32,15 +34,18 @@ import java.lang.reflect.Parameter;
 public class StandardReflectionParameterNameDiscoverer implements ParameterNameDiscoverer {
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Method method) {
 		return getParameterNames(method.getParameters());
 	}
 
 	@Override
+	@Nullable
 	public String[] getParameterNames(Constructor<?> ctor) {
 		return getParameterNames(ctor.getParameters());
 	}
 
+	@Nullable
 	private String[] getParameterNames(Parameter[] parameters) {
 		String[] parameterNames = new String[parameters.length];
 		for (int i = 0; i < parameters.length; i++) {
diff --git a/spring-core/src/main/java/org/springframework/core/annotation/AbstractAliasAwareAnnotationAttributeExtractor.java b/spring-core/src/main/java/org/springframework/core/annotation/AbstractAliasAwareAnnotationAttributeExtractor.java
index d7a7ed3561e..03551e35ee9 100644
--- a/spring-core/src/main/java/org/springframework/core/annotation/AbstractAliasAwareAnnotationAttributeExtractor.java
+++ b/spring-core/src/main/java/org/springframework/core/annotation/AbstractAliasAwareAnnotationAttributeExtractor.java
@@ -85,6 +85,7 @@ abstract class AbstractAliasAwareAnnotationAttributeExtractor<S> implements Anno
 	}
 
 	@Override
+	@Nullable
 	public final Object getAttributeValue(Method attributeMethod) {
 		String attributeName = attributeMethod.getName();
 		Object attributeValue = getRawAttributeValue(attributeMethod);
diff --git a/spring-core/src/main/java/org/springframework/core/annotation/AnnotationAwareOrderComparator.java b/spring-core/src/main/java/org/springframework/core/annotation/AnnotationAwareOrderComparator.java
index f9c07c81f11..0e19e8cf441 100644
--- a/spring-core/src/main/java/org/springframework/core/annotation/AnnotationAwareOrderComparator.java
+++ b/spring-core/src/main/java/org/springframework/core/annotation/AnnotationAwareOrderComparator.java
@@ -24,6 +24,7 @@ import java.util.List;
 
 import org.springframework.core.DecoratingProxy;
 import org.springframework.core.OrderComparator;
+import org.springframework.lang.Nullable;
 
 /**
  * {@code AnnotationAwareOrderComparator} is an extension of
@@ -58,6 +59,8 @@ public class AnnotationAwareOrderComparator extends OrderComparator {
 	 * elements, in addition to the {@link org.springframework.core.Ordered}
 	 * check in the superclass.
 	 */
+	@Override
+	@Nullable
 	protected Integer findOrder(Object obj) {
 		// Check for regular Ordered interface
 		Integer order = super.findOrder(obj);
@@ -97,6 +100,8 @@ public class AnnotationAwareOrderComparator extends OrderComparator {
 	 * annotation: typically, selecting one object over another in case of
 	 * multiple matches but only one object to be returned.
 	 */
+	@Override
+	@Nullable
 	public Integer getPriority(Object obj) {
 		if (obj instanceof Class) {
 			return OrderUtils.getPriority((Class<?>) obj);
diff --git a/spring-core/src/main/java/org/springframework/core/annotation/DefaultAnnotationAttributeExtractor.java b/spring-core/src/main/java/org/springframework/core/annotation/DefaultAnnotationAttributeExtractor.java
index 743444a8607..06d5a8af541 100644
--- a/spring-core/src/main/java/org/springframework/core/annotation/DefaultAnnotationAttributeExtractor.java
+++ b/spring-core/src/main/java/org/springframework/core/annotation/DefaultAnnotationAttributeExtractor.java
@@ -48,12 +48,14 @@ class DefaultAnnotationAttributeExtractor extends AbstractAliasAwareAnnotationAt
 
 
 	@Override
+	@Nullable
 	protected Object getRawAttributeValue(Method attributeMethod) {
 		ReflectionUtils.makeAccessible(attributeMethod);
 		return ReflectionUtils.invokeMethod(attributeMethod, getSource());
 	}
 
 	@Override
+	@Nullable
 	protected Object getRawAttributeValue(String attributeName) {
 		Method attributeMethod = ReflectionUtils.findMethod(getAnnotationType(), attributeName);
 		return (attributeMethod != null ? getRawAttributeValue(attributeMethod) : null);
diff --git a/spring-core/src/main/java/org/springframework/core/annotation/MapAnnotationAttributeExtractor.java b/spring-core/src/main/java/org/springframework/core/annotation/MapAnnotationAttributeExtractor.java
index 6eed1d0d57b..4ef4abd7b12 100644
--- a/spring-core/src/main/java/org/springframework/core/annotation/MapAnnotationAttributeExtractor.java
+++ b/spring-core/src/main/java/org/springframework/core/annotation/MapAnnotationAttributeExtractor.java
@@ -60,11 +60,13 @@ class MapAnnotationAttributeExtractor extends AbstractAliasAwareAnnotationAttrib
 
 
 	@Override
+	@Nullable
 	protected Object getRawAttributeValue(Method attributeMethod) {
 		return getRawAttributeValue(attributeMethod.getName());
 	}
 
 	@Override
+	@Nullable
 	protected Object getRawAttributeValue(String attributeName) {
 		return getSource().get(attributeName);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/convert/converter/ConvertingComparator.java b/spring-core/src/main/java/org/springframework/core/convert/converter/ConvertingComparator.java
index 7dbfed09931..c5af0d7631a 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/converter/ConvertingComparator.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/converter/ConvertingComparator.java
@@ -20,6 +20,7 @@ import java.util.Comparator;
 import java.util.Map;
 
 import org.springframework.core.convert.ConversionService;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.comparator.Comparators;
 
@@ -119,6 +120,7 @@ public class ConvertingComparator<S, T> implements Comparator<S> {
 		}
 
 		@Override
+		@Nullable
 		public T convert(S source) {
 			return this.conversionService.convert(source, this.targetType);
 		}
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/ArrayToArrayConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/ArrayToArrayConverter.java
index fb5962c585a..fbeba2bfa61 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/ArrayToArrayConverter.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/ArrayToArrayConverter.java
@@ -60,6 +60,7 @@ final class ArrayToArrayConverter implements ConditionalGenericConverter {
 	}
 
 	@Override
+	@Nullable
 	public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		if (this.conversionService instanceof GenericConversionService) {
 			TypeDescriptor targetElement = targetType.getElementTypeDescriptor();
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java b/spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java
index 08f2dbfa28b..aca727f40c5 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java
@@ -168,12 +168,14 @@ public class GenericConversionService implements ConfigurableConversionService {
 
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public <T> T convert(@Nullable Object source, Class<T> targetType) {
 		Assert.notNull(targetType, "Target type to convert to cannot be null");
 		return (T) convert(source, TypeDescriptor.forObject(source), TypeDescriptor.valueOf(targetType));
 	}
 
 	@Override
+	@Nullable
 	public Object convert(@Nullable Object source, @Nullable TypeDescriptor sourceType, TypeDescriptor targetType) {
 		Assert.notNull(targetType, "Target type to convert to cannot be null");
 		if (sourceType == null) {
@@ -426,6 +428,7 @@ public class GenericConversionService implements ConfigurableConversionService {
 		}
 
 		@Override
+		@Nullable
 		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			if (source == null) {
 				return convertNullSource(sourceType, targetType);
@@ -694,6 +697,7 @@ public class GenericConversionService implements ConfigurableConversionService {
 		}
 
 		@Override
+		@Nullable
 		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			return source;
 		}
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/MapToMapConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/MapToMapConverter.java
index 28b4fbd1dc9..308ec075921 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/MapToMapConverter.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/MapToMapConverter.java
@@ -62,6 +62,7 @@ final class MapToMapConverter implements ConditionalGenericConverter {
 
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		if (source == null) {
 			return null;
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/ObjectToOptionalConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/ObjectToOptionalConverter.java
index c5e30021c3d..b7564bcb618 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/ObjectToOptionalConverter.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/ObjectToOptionalConverter.java
@@ -60,7 +60,6 @@ final class ObjectToOptionalConverter implements ConditionalGenericConverter {
 	}
 
 	@Override
-	@Nullable
 	public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		if (source == null) {
 			return Optional.empty();
diff --git a/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java b/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
index 5b2db4a4955..b50b8b8242d 100644
--- a/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
+++ b/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
@@ -386,6 +386,7 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
 		catch (AccessControlException ex) {
 			return (Map) new ReadOnlySystemAttributesMap() {
 				@Override
+				@Nullable
 				protected String getSystemAttribute(String attributeName) {
 					try {
 						return System.getenv(attributeName);
@@ -426,6 +427,7 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
 		catch (AccessControlException ex) {
 			return (Map) new ReadOnlySystemAttributesMap() {
 				@Override
+				@Nullable
 				protected String getSystemAttribute(String attributeName) {
 					try {
 						return System.getProperty(attributeName);
@@ -524,6 +526,7 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
 	}
 
 	@Override
+	@Nullable
 	public String getProperty(String key) {
 		return this.propertyResolver.getProperty(key);
 	}
@@ -534,6 +537,7 @@ public abstract class AbstractEnvironment implements ConfigurableEnvironment {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getProperty(String key, Class<T> targetType) {
 		return this.propertyResolver.getProperty(key, targetType);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java b/spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java
index dfec9f14382..62b17613dbb 100644
--- a/spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java
+++ b/spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java
@@ -160,6 +160,7 @@ public abstract class AbstractPropertyResolver implements ConfigurablePropertyRe
 	}
 
 	@Override
+	@Nullable
 	public String getProperty(String key) {
 		return getProperty(key, String.class);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java b/spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java
index f4905331dad..c06d7028df8 100644
--- a/spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java
@@ -266,6 +266,7 @@ public abstract class CommandLinePropertySource<T> extends EnumerablePropertySou
 	 * #getOptionValues(String)} method.
 	 */
 	@Override
+	@Nullable
 	public final String getProperty(String name) {
 		if (this.nonOptionArgsPropertyName.equals(name)) {
 			Collection<String> nonOptionArguments = this.getNonOptionArgs();
diff --git a/spring-core/src/main/java/org/springframework/core/env/CompositePropertySource.java b/spring-core/src/main/java/org/springframework/core/env/CompositePropertySource.java
index 103f92b1197..f54c0e97a46 100644
--- a/spring-core/src/main/java/org/springframework/core/env/CompositePropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/CompositePropertySource.java
@@ -23,6 +23,7 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -54,6 +55,7 @@ public class CompositePropertySource extends EnumerablePropertySource<Object> {
 
 
 	@Override
+	@Nullable
 	public Object getProperty(String name) {
 		for (PropertySource<?> propertySource : this.propertySources) {
 			Object candidate = propertySource.getProperty(name);
diff --git a/spring-core/src/main/java/org/springframework/core/env/JOptCommandLinePropertySource.java b/spring-core/src/main/java/org/springframework/core/env/JOptCommandLinePropertySource.java
index 19733690e5d..161802f7fae 100644
--- a/spring-core/src/main/java/org/springframework/core/env/JOptCommandLinePropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/JOptCommandLinePropertySource.java
@@ -23,6 +23,8 @@ import java.util.List;
 import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@link CommandLinePropertySource} implementation backed by a JOpt {@link OptionSet}.
  *
@@ -94,6 +96,7 @@ public class JOptCommandLinePropertySource extends CommandLinePropertySource<Opt
 	}
 
 	@Override
+	@Nullable
 	public List<String> getOptionValues(String name) {
 		List<?> argValues = this.source.valuesOf(name);
 		List<String> stringArgValues = new ArrayList<>();
diff --git a/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java b/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
index 0a4a173fa0e..0d1dab096a1 100644
--- a/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java
@@ -18,6 +18,7 @@ package org.springframework.core.env;
 
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -36,6 +37,7 @@ public class MapPropertySource extends EnumerablePropertySource<Map<String, Obje
 
 
 	@Override
+	@Nullable
 	public Object getProperty(String name) {
 		return this.source.get(name);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/env/MutablePropertySources.java b/spring-core/src/main/java/org/springframework/core/env/MutablePropertySources.java
index d450ef5fa4e..5a32be44c2d 100644
--- a/spring-core/src/main/java/org/springframework/core/env/MutablePropertySources.java
+++ b/spring-core/src/main/java/org/springframework/core/env/MutablePropertySources.java
@@ -79,6 +79,7 @@ public class MutablePropertySources implements PropertySources {
 	}
 
 	@Override
+	@Nullable
 	public PropertySource<?> get(String name) {
 		int index = this.propertySourceList.indexOf(PropertySource.named(name));
 		return (index != -1 ? this.propertySourceList.get(index) : null);
diff --git a/spring-core/src/main/java/org/springframework/core/env/PropertySource.java b/spring-core/src/main/java/org/springframework/core/env/PropertySource.java
index b6275ac6f13..a983fff3ff8 100644
--- a/spring-core/src/main/java/org/springframework/core/env/PropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/PropertySource.java
@@ -210,6 +210,7 @@ public abstract class PropertySource<T> {
 		 * Always returns {@code null}.
 		 */
 		@Override
+		@Nullable
 		public String getProperty(String name) {
 			return null;
 		}
@@ -239,6 +240,7 @@ public abstract class PropertySource<T> {
 		}
 
 		@Override
+		@Nullable
 		public String getProperty(String name) {
 			throw new UnsupportedOperationException(USAGE_ERROR);
 		}
diff --git a/spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java b/spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java
index d2cf0bfea81..92580212c98 100644
--- a/spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java
+++ b/spring-core/src/main/java/org/springframework/core/env/PropertySourcesPropertyResolver.java
@@ -57,16 +57,19 @@ public class PropertySourcesPropertyResolver extends AbstractPropertyResolver {
 	}
 
 	@Override
+	@Nullable
 	public String getProperty(String key) {
 		return getProperty(key, String.class, true);
 	}
 
 	@Override
+	@Nullable
 	public <T> T getProperty(String key, Class<T> targetValueType) {
 		return getProperty(key, targetValueType, true);
 	}
 
 	@Override
+	@Nullable
 	protected String getPropertyAsRawString(String key) {
 		return getProperty(key, String.class, false);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java b/spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java
index f1b1f8d7b5f..c29e5f5a13c 100644
--- a/spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java
@@ -18,6 +18,8 @@ package org.springframework.core.env;
 
 import java.util.List;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@link CommandLinePropertySource} implementation backed by a simple String array.
  *
@@ -109,6 +111,7 @@ public class SimpleCommandLinePropertySource extends CommandLinePropertySource<C
 	}
 
 	@Override
+	@Nullable
 	protected List<String> getOptionValues(String name) {
 		return this.source.getOptionValues(name);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java b/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
index c942d521c28..bcfd91580ae 100644
--- a/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
+++ b/spring-core/src/main/java/org/springframework/core/env/SystemEnvironmentPropertySource.java
@@ -88,6 +88,7 @@ public class SystemEnvironmentPropertySource extends MapPropertySource {
 	 * any underscore/uppercase variant thereof exists in this property source.
 	 */
 	@Override
+	@Nullable
 	public Object getProperty(String name) {
 		String actualName = resolvePropertyName(name);
 		if (logger.isDebugEnabled() && !name.equals(actualName)) {
diff --git a/spring-core/src/main/java/org/springframework/core/io/AbstractResource.java b/spring-core/src/main/java/org/springframework/core/io/AbstractResource.java
index 9e42a43e18f..6beef08a30d 100644
--- a/spring-core/src/main/java/org/springframework/core/io/AbstractResource.java
+++ b/spring-core/src/main/java/org/springframework/core/io/AbstractResource.java
@@ -27,6 +27,7 @@ import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
 
 import org.springframework.core.NestedIOException;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ResourceUtils;
 
 /**
@@ -202,6 +203,7 @@ public abstract class AbstractResource implements Resource {
 	 * assuming that this resource type does not have a filename.
 	 */
 	@Override
+	@Nullable
 	public String getFilename() {
 		return null;
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java b/spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java
index 2e6be9ddd40..a4384dea9b1 100644
--- a/spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java
+++ b/spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java
@@ -211,6 +211,7 @@ public class ClassPathResource extends AbstractFileResolvingResource {
 	 * @see org.springframework.util.StringUtils#getFilename(String)
 	 */
 	@Override
+	@Nullable
 	public String getFilename() {
 		return StringUtils.getFilename(this.path);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java b/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
index 4b9febb05f0..cde09fe8e54 100644
--- a/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
+++ b/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
@@ -91,6 +91,7 @@ public class DefaultResourceLoader implements ResourceLoader {
 	 * @see ClassPathResource
 	 */
 	@Override
+	@Nullable
 	public ClassLoader getClassLoader() {
 		return (this.classLoader != null ? this.classLoader : ClassUtils.getDefaultClassLoader());
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java b/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java
index 128f532c7f2..1500b179d37 100644
--- a/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java
+++ b/spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java
@@ -244,6 +244,7 @@ public class PathMatchingResourcePatternResolver implements ResourcePatternResol
 	}
 
 	@Override
+	@Nullable
 	public ClassLoader getClassLoader() {
 		return getResourceLoader().getClassLoader();
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/type/StandardAnnotationMetadata.java b/spring-core/src/main/java/org/springframework/core/type/StandardAnnotationMetadata.java
index 397d17abdf3..46d28f407c0 100644
--- a/spring-core/src/main/java/org/springframework/core/type/StandardAnnotationMetadata.java
+++ b/spring-core/src/main/java/org/springframework/core/type/StandardAnnotationMetadata.java
@@ -24,6 +24,7 @@ import java.util.Map;
 import java.util.Set;
 
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.util.MultiValueMap;
 
 /**
@@ -115,17 +116,20 @@ public class StandardAnnotationMetadata extends StandardClassMetadata implements
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		return (this.annotations.length > 0 ? AnnotatedElementUtils.getMergedAnnotationAttributes(
 				getIntrospectedClass(), annotationName, classValuesAsString, this.nestedAnnotationsAsMap) : null);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName) {
 		return getAllAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		return (this.annotations.length > 0 ? AnnotatedElementUtils.getAllAnnotationAttributes(
 				getIntrospectedClass(), annotationName, classValuesAsString, this.nestedAnnotationsAsMap) : null);
diff --git a/spring-core/src/main/java/org/springframework/core/type/StandardClassMetadata.java b/spring-core/src/main/java/org/springframework/core/type/StandardClassMetadata.java
index 9330e29b1a2..9a0eee891e4 100644
--- a/spring-core/src/main/java/org/springframework/core/type/StandardClassMetadata.java
+++ b/spring-core/src/main/java/org/springframework/core/type/StandardClassMetadata.java
@@ -19,6 +19,7 @@ package org.springframework.core.type;
 import java.lang.reflect.Modifier;
 import java.util.LinkedHashSet;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -93,6 +94,7 @@ public class StandardClassMetadata implements ClassMetadata {
 	}
 
 	@Override
+	@Nullable
 	public String getEnclosingClassName() {
 		Class<?> enclosingClass = this.introspectedClass.getEnclosingClass();
 		return (enclosingClass != null ? enclosingClass.getName() : null);
@@ -104,6 +106,7 @@ public class StandardClassMetadata implements ClassMetadata {
 	}
 
 	@Override
+	@Nullable
 	public String getSuperClassName() {
 		Class<?> superClass = this.introspectedClass.getSuperclass();
 		return (superClass != null ? superClass.getName() : null);
diff --git a/spring-core/src/main/java/org/springframework/core/type/StandardMethodMetadata.java b/spring-core/src/main/java/org/springframework/core/type/StandardMethodMetadata.java
index 485dd3b6b2d..d745d43a012 100644
--- a/spring-core/src/main/java/org/springframework/core/type/StandardMethodMetadata.java
+++ b/spring-core/src/main/java/org/springframework/core/type/StandardMethodMetadata.java
@@ -21,6 +21,7 @@ import java.lang.reflect.Modifier;
 import java.util.Map;
 
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.MultiValueMap;
 
@@ -115,22 +116,26 @@ public class StandardMethodMetadata implements MethodMetadata {
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getAnnotationAttributes(String annotationName) {
 		return getAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		return AnnotatedElementUtils.getMergedAnnotationAttributes(this.introspectedMethod,
 				annotationName, classValuesAsString, this.nestedAnnotationsAsMap);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName) {
 		return getAllAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		return AnnotatedElementUtils.getAllAnnotationAttributes(this.introspectedMethod,
 				annotationName, classValuesAsString, this.nestedAnnotationsAsMap);
diff --git a/spring-core/src/main/java/org/springframework/core/type/classreading/AnnotationMetadataReadingVisitor.java b/spring-core/src/main/java/org/springframework/core/type/classreading/AnnotationMetadataReadingVisitor.java
index 1158c0dce63..b66a8265414 100644
--- a/spring-core/src/main/java/org/springframework/core/type/classreading/AnnotationMetadataReadingVisitor.java
+++ b/spring-core/src/main/java/org/springframework/core/type/classreading/AnnotationMetadataReadingVisitor.java
@@ -124,11 +124,13 @@ public class AnnotationMetadataReadingVisitor extends ClassMetadataReadingVisito
 	}
 
 	@Override
+	@Nullable
 	public AnnotationAttributes getAnnotationAttributes(String annotationName) {
 		return getAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public AnnotationAttributes getAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		AnnotationAttributes raw = AnnotationReadingVisitorUtils.getMergedAnnotationAttributes(
 				this.attributesMap, this.metaAnnotationMap, annotationName);
@@ -140,11 +142,13 @@ public class AnnotationMetadataReadingVisitor extends ClassMetadataReadingVisito
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName) {
 		return getAllAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		MultiValueMap<String, Object> allAttributes = new LinkedMultiValueMap<>();
 		List<AnnotationAttributes> attributes = this.attributesMap.get(annotationName);
diff --git a/spring-core/src/main/java/org/springframework/core/type/classreading/MethodMetadataReadingVisitor.java b/spring-core/src/main/java/org/springframework/core/type/classreading/MethodMetadataReadingVisitor.java
index fdf8f213de0..98540888291 100644
--- a/spring-core/src/main/java/org/springframework/core/type/classreading/MethodMetadataReadingVisitor.java
+++ b/spring-core/src/main/java/org/springframework/core/type/classreading/MethodMetadataReadingVisitor.java
@@ -116,11 +116,13 @@ public class MethodMetadataReadingVisitor extends MethodVisitor implements Metho
 	}
 
 	@Override
+	@Nullable
 	public AnnotationAttributes getAnnotationAttributes(String annotationName) {
 		return getAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public AnnotationAttributes getAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		AnnotationAttributes raw = AnnotationReadingVisitorUtils.getMergedAnnotationAttributes(
 				this.attributesMap, this.metaAnnotationMap, annotationName);
@@ -132,11 +134,13 @@ public class MethodMetadataReadingVisitor extends MethodVisitor implements Metho
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName) {
 		return getAllAnnotationAttributes(annotationName, false);
 	}
 
 	@Override
+	@Nullable
 	public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName, boolean classValuesAsString) {
 		if (!this.attributesMap.containsKey(annotationName)) {
 			return null;
diff --git a/spring-core/src/main/java/org/springframework/core/type/filter/AnnotationTypeFilter.java b/spring-core/src/main/java/org/springframework/core/type/filter/AnnotationTypeFilter.java
index 74fd6fab2a1..7416f22662d 100644
--- a/spring-core/src/main/java/org/springframework/core/type/filter/AnnotationTypeFilter.java
+++ b/spring-core/src/main/java/org/springframework/core/type/filter/AnnotationTypeFilter.java
@@ -94,11 +94,13 @@ public class AnnotationTypeFilter extends AbstractTypeHierarchyTraversingFilter
 	}
 
 	@Override
+	@Nullable
 	protected Boolean matchSuperClass(String superClassName) {
 		return hasAnnotation(superClassName);
 	}
 
 	@Override
+	@Nullable
 	protected Boolean matchInterface(String interfaceName) {
 		return hasAnnotation(interfaceName);
 	}
diff --git a/spring-core/src/main/java/org/springframework/core/type/filter/AssignableTypeFilter.java b/spring-core/src/main/java/org/springframework/core/type/filter/AssignableTypeFilter.java
index 79665b8d3e3..1e5b6f6e194 100644
--- a/spring-core/src/main/java/org/springframework/core/type/filter/AssignableTypeFilter.java
+++ b/spring-core/src/main/java/org/springframework/core/type/filter/AssignableTypeFilter.java
@@ -55,11 +55,13 @@ public class AssignableTypeFilter extends AbstractTypeHierarchyTraversingFilter
 	}
 
 	@Override
+	@Nullable
 	protected Boolean matchSuperClass(String superClassName) {
 		return matchTargetType(superClassName);
 	}
 
 	@Override
+	@Nullable
 	protected Boolean matchInterface(String interfaceName) {
 		return matchTargetType(interfaceName);
 	}
diff --git a/spring-core/src/main/java/org/springframework/lang/Nullable.java b/spring-core/src/main/java/org/springframework/lang/Nullable.java
index 547b3cfd0ab..a1cb932b4e9 100644
--- a/spring-core/src/main/java/org/springframework/lang/Nullable.java
+++ b/spring-core/src/main/java/org/springframework/lang/Nullable.java
@@ -29,8 +29,9 @@ import javax.annotation.meta.When;
  * A common Spring annotation to declare that the annotated parameter,
  * return value or field could be {@code null} under some circumstances.
  *
- * <p>Should be used at parameters and return values level in association
- * with {@link NonNullApi} package-level annotations.
+ * <p>Should be used at parameters, return values and optionally field level in association
+ * with {@link NonNullApi} package-level annotations. Methods overrides should repeat parent
+ * parameter or return value {@code @Nullable} annotations unless they behave differently.
  *
  * <p>Leverages JSR-305 meta-annotations to indicate its semantics to
  * common tools with JSR-305 support.
diff --git a/spring-core/src/main/java/org/springframework/util/CollectionUtils.java b/spring-core/src/main/java/org/springframework/util/CollectionUtils.java
index 12718ac3006..1cdfa35b549 100644
--- a/spring-core/src/main/java/org/springframework/util/CollectionUtils.java
+++ b/spring-core/src/main/java/org/springframework/util/CollectionUtils.java
@@ -405,6 +405,7 @@ public abstract class CollectionUtils {
 		}
 
 		@Override
+		@Nullable
 		public V getFirst(K key) {
 			List<V> values = this.map.get(key);
 			return (values != null ? values.get(0) : null);
diff --git a/spring-core/src/main/java/org/springframework/util/ConcurrentReferenceHashMap.java b/spring-core/src/main/java/org/springframework/util/ConcurrentReferenceHashMap.java
index 598b49325cb..03f9f241fc0 100644
--- a/spring-core/src/main/java/org/springframework/util/ConcurrentReferenceHashMap.java
+++ b/spring-core/src/main/java/org/springframework/util/ConcurrentReferenceHashMap.java
@@ -1005,6 +1005,7 @@ public class ConcurrentReferenceHashMap<K, V> extends AbstractMap<K, V> implemen
 		}
 
 		@Override
+		@Nullable
 		public Reference<K, V> getNext() {
 			return this.nextReference;
 		}
@@ -1041,6 +1042,7 @@ public class ConcurrentReferenceHashMap<K, V> extends AbstractMap<K, V> implemen
 		}
 
 		@Override
+		@Nullable
 		public Reference<K, V> getNext() {
 			return this.nextReference;
 		}
diff --git a/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java b/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java
index 9c9187e5594..5c20bf35f5b 100644
--- a/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java
+++ b/spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java
@@ -76,6 +76,7 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	// MultiValueMap implementation
 
 	@Override
+	@Nullable
 	public V getFirst(K key) {
 		List<V> values = this.targetMap.get(key);
 		return (values != null ? values.get(0) : null);
diff --git a/spring-core/src/main/java/org/springframework/util/SystemPropertyUtils.java b/spring-core/src/main/java/org/springframework/util/SystemPropertyUtils.java
index 23ddd15c81a..269da7d5a64 100644
--- a/spring-core/src/main/java/org/springframework/util/SystemPropertyUtils.java
+++ b/spring-core/src/main/java/org/springframework/util/SystemPropertyUtils.java
@@ -16,6 +16,8 @@
 
 package org.springframework.util;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Helper class for resolving placeholders in texts. Usually applied to file paths.
  *
@@ -94,6 +96,7 @@ public abstract class SystemPropertyUtils {
 		}
 
 		@Override
+		@Nullable
 		public String resolvePlaceholder(String placeholderName) {
 			try {
 				String propVal = System.getProperty(placeholderName);
diff --git a/spring-expression/src/main/java/org/springframework/expression/common/CompositeStringExpression.java b/spring-expression/src/main/java/org/springframework/expression/common/CompositeStringExpression.java
index 7eab31a4452..8a44241881e 100644
--- a/spring-expression/src/main/java/org/springframework/expression/common/CompositeStringExpression.java
+++ b/spring-expression/src/main/java/org/springframework/expression/common/CompositeStringExpression.java
@@ -76,6 +76,7 @@ public class CompositeStringExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(@Nullable Class<T> expectedResultType) throws EvaluationException {
 		Object value = getValue();
 		return ExpressionUtils.convertTypedValue(null, new TypedValue(value), expectedResultType);
@@ -94,6 +95,7 @@ public class CompositeStringExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(Object rootObject, @Nullable Class<T> desiredResultType) throws EvaluationException {
 		Object value = getValue(rootObject);
 		return ExpressionUtils.convertTypedValue(null, new TypedValue(value), desiredResultType);
@@ -112,6 +114,7 @@ public class CompositeStringExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, @Nullable Class<T> expectedResultType)
 			throws EvaluationException {
 
@@ -132,6 +135,7 @@ public class CompositeStringExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, Object rootObject, @Nullable Class<T> desiredResultType)
 			throws EvaluationException {
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/common/LiteralExpression.java b/spring-expression/src/main/java/org/springframework/expression/common/LiteralExpression.java
index abbe36e33dc..9fb60b340f7 100644
--- a/spring-expression/src/main/java/org/springframework/expression/common/LiteralExpression.java
+++ b/spring-expression/src/main/java/org/springframework/expression/common/LiteralExpression.java
@@ -60,6 +60,7 @@ public class LiteralExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(@Nullable Class<T> expectedResultType) throws EvaluationException {
 		Object value = getValue();
 		return ExpressionUtils.convertTypedValue(null, new TypedValue(value), expectedResultType);
@@ -71,6 +72,7 @@ public class LiteralExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(Object rootObject, @Nullable Class<T> desiredResultType) throws EvaluationException {
 		Object value = getValue(rootObject);
 		return ExpressionUtils.convertTypedValue(null, new TypedValue(value), desiredResultType);
@@ -82,6 +84,7 @@ public class LiteralExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, @Nullable Class<T> expectedResultType)
 			throws EvaluationException {
 
@@ -95,6 +98,7 @@ public class LiteralExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, Object rootObject, @Nullable Class<T> desiredResultType)
 			throws EvaluationException {
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java b/spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java
index 63217330dd2..745bab0006a 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java
@@ -104,6 +104,7 @@ public abstract class SpelNodeImpl implements SpelNode, Opcodes {
 	}
 
 	@Override
+	@Nullable
 	public final Object getValue(ExpressionState expressionState) throws EvaluationException {
 		return getValueInternal(expressionState).getValue();
 	}
@@ -136,6 +137,7 @@ public abstract class SpelNodeImpl implements SpelNode, Opcodes {
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getObjectClass(@Nullable Object obj) {
 		if (obj == null) {
 			return null;
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java b/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
index ae895ce2883..fbb6fb76978 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
@@ -114,6 +114,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue() throws EvaluationException {
 		if (this.compiledAst != null) {
 			try {
@@ -143,6 +144,7 @@ public class SpelExpression implements Expression {
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T getValue(@Nullable Class<T> expectedResultType) throws EvaluationException {
 		if (this.compiledAst != null) {
 			try {
@@ -179,6 +181,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(Object rootObject) throws EvaluationException {
 		if (this.compiledAst != null) {
 			try {
@@ -206,6 +209,7 @@ public class SpelExpression implements Expression {
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T getValue(Object rootObject, @Nullable Class<T> expectedResultType) throws EvaluationException {
 		if (this.compiledAst != null) {
 			try {
@@ -240,6 +244,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(EvaluationContext context) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
 
@@ -269,6 +274,7 @@ public class SpelExpression implements Expression {
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, @Nullable Class<T> expectedResultType) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
 
@@ -303,6 +309,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(EvaluationContext context, Object rootObject) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
 
@@ -331,6 +338,7 @@ public class SpelExpression implements Expression {
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T getValue(EvaluationContext context, Object rootObject, @Nullable Class<T> expectedResultType)
 			throws EvaluationException {
 
@@ -366,16 +374,19 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getValueType() throws EvaluationException {
 		return getValueType(getEvaluationContext());
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getValueType(Object rootObject) throws EvaluationException {
 		return getValueType(getEvaluationContext(), rootObject);
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getValueType(EvaluationContext context) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
 		ExpressionState expressionState = new ExpressionState(context, this.configuration);
@@ -384,6 +395,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getValueType(EvaluationContext context, Object rootObject) throws EvaluationException {
 		ExpressionState expressionState = new ExpressionState(context, toTypedValue(rootObject), this.configuration);
 		TypeDescriptor typeDescriptor = this.ast.getValueInternal(expressionState).getTypeDescriptor();
@@ -391,11 +403,13 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public TypeDescriptor getValueTypeDescriptor() throws EvaluationException {
 		return getValueTypeDescriptor(getEvaluationContext());
 	}
 
 	@Override
+	@Nullable
 	public TypeDescriptor getValueTypeDescriptor(Object rootObject) throws EvaluationException {
 		ExpressionState expressionState =
 				new ExpressionState(getEvaluationContext(), toTypedValue(rootObject), this.configuration);
@@ -403,6 +417,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public TypeDescriptor getValueTypeDescriptor(EvaluationContext context) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
 		ExpressionState expressionState = new ExpressionState(context, this.configuration);
@@ -410,6 +425,7 @@ public class SpelExpression implements Expression {
 	}
 
 	@Override
+	@Nullable
 	public TypeDescriptor getValueTypeDescriptor(EvaluationContext context, Object rootObject)
 			throws EvaluationException {
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveConstructorResolver.java b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveConstructorResolver.java
index 9c0cc004aab..d75b21e9554 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveConstructorResolver.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveConstructorResolver.java
@@ -29,6 +29,7 @@ import org.springframework.expression.ConstructorResolver;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.EvaluationException;
 import org.springframework.expression.TypeConverter;
+import org.springframework.lang.Nullable;
 
 /**
  * A constructor resolver that uses reflection to locate the constructor that should be invoked.
@@ -49,6 +50,7 @@ public class ReflectiveConstructorResolver implements ConstructorResolver {
 	 * </ol>
 	 */
 	@Override
+	@Nullable
 	public ConstructorExecutor resolve(EvaluationContext context, String typeName, List<TypeDescriptor> argumentTypes)
 			throws AccessException {
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveMethodResolver.java b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveMethodResolver.java
index 42c780354db..09cb807f801 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveMethodResolver.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectiveMethodResolver.java
@@ -103,6 +103,7 @@ public class ReflectiveMethodResolver implements MethodResolver {
 	 * </ol>
 	 */
 	@Override
+	@Nullable
 	public MethodExecutor resolve(EvaluationContext context, Object targetObject, String name,
 			List<TypeDescriptor> argumentTypes) throws AccessException {
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectivePropertyAccessor.java b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectivePropertyAccessor.java
index 81dc0bf12bc..9eb242c0936 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectivePropertyAccessor.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectivePropertyAccessor.java
@@ -84,6 +84,7 @@ public class ReflectivePropertyAccessor implements PropertyAccessor {
 	 * Returns {@code null} which means this is a general purpose accessor.
 	 */
 	@Override
+	@Nullable
 	public Class<?>[] getSpecificTargetClasses() {
 		return null;
 	}
@@ -590,6 +591,7 @@ public class ReflectivePropertyAccessor implements PropertyAccessor {
 		}
 
 		@Override
+		@Nullable
 		public Class<?>[] getSpecificTargetClasses() {
 			throw new UnsupportedOperationException("Should not be called on an OptimalPropertyAccessor");
 		}
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardEvaluationContext.java b/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardEvaluationContext.java
index 9786eac55b2..ccb72302b5f 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardEvaluationContext.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardEvaluationContext.java
@@ -222,6 +222,7 @@ public class StandardEvaluationContext implements EvaluationContext {
 	}
 
 	@Override
+	@Nullable
 	public Object lookupVariable(String name) {
 		return this.variables.get(name);
 	}
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java b/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java
index 6bacbd6b133..fce9643b650 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/support/StandardTypeConverter.java
@@ -63,6 +63,7 @@ public class StandardTypeConverter implements TypeConverter {
 	}
 
 	@Override
+	@Nullable
 	public Object convertValue(@Nullable Object value, @Nullable TypeDescriptor sourceType, TypeDescriptor targetType) {
 		try {
 			return this.conversionService.convert(value, sourceType, targetType);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java
index 8118606b02f..465777b5e62 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java
@@ -147,6 +147,7 @@ public interface JdbcOperations {
 	 * @throws DataAccessException if there is any problem executing the query
 	 * @see #queryForObject(String, Object[], RowMapper)
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
@@ -531,6 +532,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Object[] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
@@ -549,6 +551,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Object[] args, RowMapper<T> rowMapper) throws DataAccessException;
 
 	/**
@@ -566,6 +569,7 @@ public interface JdbcOperations {
 	 * return exactly one row
 	 * @throws DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object... args) throws DataAccessException;
 
 	/**
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java
index b6d58a8b39e..bb0ee338953 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java
@@ -316,6 +316,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(ConnectionCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
@@ -361,6 +362,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(StatementCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 
@@ -395,6 +397,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 		class ExecuteStatementCallback implements StatementCallback<Object>, SqlProvider {
 			@Override
+			@Nullable
 			public Object doInStatement(Statement stmt) throws SQLException {
 				stmt.execute(sql);
 				return null;
@@ -408,6 +411,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(final String sql, final ResultSetExtractor<T> rse) throws DataAccessException {
 		Assert.notNull(sql, "SQL must not be null");
 		Assert.notNull(rse, "ResultSetExtractor must not be null");
@@ -416,6 +420,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 		class QueryStatementCallback implements StatementCallback<T>, SqlProvider {
 			@Override
+			@Nullable
 			public T doInStatement(Statement stmt) throws SQLException {
 				ResultSet rs = null;
 				try {
@@ -452,12 +457,14 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, rowMapper);
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Class<T> requiredType) throws DataAccessException {
 		return queryForObject(sql, getSingleColumnRowMapper(requiredType));
 	}
@@ -561,6 +568,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 			}
 
 			@Override
+			@Nullable
 			public String getSql() {
 				return this.currSql;
 			}
@@ -577,6 +585,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -619,6 +628,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimplePreparedStatementCreator(sql), action);
 	}
@@ -645,6 +655,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 
 		return execute(psc, new PreparedStatementCallback<T>() {
 			@Override
+			@Nullable
 			public T doInPreparedStatement(PreparedStatement ps) throws SQLException {
 				ResultSet rs = null;
 				try {
@@ -665,26 +676,31 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(PreparedStatementCreator psc, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(psc, null, rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, @Nullable PreparedStatementSetter pss, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(new SimplePreparedStatementCreator(sql), pss, rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, Object[] args, int[] argTypes, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgTypePreparedStatementSetter(args, argTypes), rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, @Nullable Object[] args, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, ResultSetExtractor<T> rse, @Nullable Object... args) throws DataAccessException {
 		return query(sql, newArgPreparedStatementSetter(args), rse);
 	}
@@ -740,6 +756,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Object[] args, int[] argTypes, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
@@ -748,18 +765,21 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, @Nullable Object[] args, RowMapper<T> rowMapper) throws DataAccessException {
 		List<T> results = query(sql, args, new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, RowMapper<T> rowMapper, @Nullable Object... args) throws DataAccessException {
 		List<T> results = query(sql, args, new RowMapperResultSetExtractor<>(rowMapper, 1));
 		return DataAccessUtils.requiredSingleResult(results);
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Object[] args, int[] argTypes, Class<T> requiredType)
 			throws DataAccessException {
 
@@ -1010,6 +1030,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(CallableStatementCreator csc, CallableStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -1052,6 +1073,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String callString, CallableStatementCallback<T> action) throws DataAccessException {
 		return execute(new SimpleCallableStatementCreator(callString), action);
 	}
@@ -1523,6 +1545,7 @@ public class JdbcTemplate extends JdbcAccessor implements JdbcOperations {
 		}
 
 		@Override
+		@Nullable
 		public Object extractData(ResultSet rs) throws SQLException {
 			while (rs.next()) {
 				this.rch.processRow(rs);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/ParameterMapper.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/ParameterMapper.java
index 0c7833ad8cf..8198084ee22 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/ParameterMapper.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/ParameterMapper.java
@@ -20,8 +20,6 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.Map;
 
-import org.springframework.lang.Nullable;
-
 /**
  * Implement this interface when parameters need to be customized based
  * on the connection. We might need to do this to make use of proprietary
@@ -45,7 +43,6 @@ public interface ParameterMapper {
 	 * parameter values (that is, there's no need to catch SQLException)
 	 * @return Map of input parameters, keyed by name (never {@code null})
 	 */
-	@Nullable
 	Map<String, ?> createMap(Connection con) throws SQLException;
 
 }
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/SingleColumnRowMapper.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/SingleColumnRowMapper.java
index b49a01c1094..2b6b66a74b9 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/SingleColumnRowMapper.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/SingleColumnRowMapper.java
@@ -86,6 +86,7 @@ public class SingleColumnRowMapper<T> implements RowMapper<T> {
 	 */
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public T mapRow(ResultSet rs, int rowNum) throws SQLException {
 		// Validate column count.
 		ResultSetMetaData rsmd = rs.getMetaData();
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/Db2CallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/Db2CallMetaDataProvider.java
index 8306c952f7b..ca4a4bd1f35 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/Db2CallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/Db2CallMetaDataProvider.java
@@ -65,6 +65,7 @@ public class Db2CallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName != null) {
 			return super.metaDataSchemaNameToUse(schemaName);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/DerbyCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/DerbyCallMetaDataProvider.java
index 4de537527de..ceed04db89f 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/DerbyCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/DerbyCallMetaDataProvider.java
@@ -36,6 +36,7 @@ public class DerbyCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName != null) {
 			return super.metaDataSchemaNameToUse(schemaName);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java
index 2e1bbca6c00..2592525cd51 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java
@@ -119,6 +119,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String procedureNameToUse(@Nullable String procedureName) {
 		if (procedureName == null) {
 			return null;
@@ -135,6 +136,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String catalogNameToUse(@Nullable String catalogName) {
 		if (catalogName == null) {
 			return null;
@@ -151,6 +153,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String schemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return null;
@@ -167,6 +170,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		if (isSupportsCatalogsInProcedureCalls()) {
 			return catalogNameToUse(catalogName);
@@ -177,6 +181,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (isSupportsSchemasInProcedureCalls()) {
 			return schemaNameToUse(schemaName);
@@ -187,6 +192,7 @@ public class GenericCallMetaDataProvider implements CallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java
index e00aa84e106..f72d7fd00eb 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java
@@ -124,6 +124,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String getSimpleQueryForGetGeneratedKey(String tableName, String keyColumnName) {
 		return null;
 	}
@@ -222,6 +223,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String tableNameToUse(@Nullable String tableName) {
 		if (tableName == null) {
 			return null;
@@ -238,6 +240,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String catalogNameToUse(@Nullable String catalogName) {
 		if (catalogName == null) {
 			return null;
@@ -254,6 +257,7 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String schemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return null;
@@ -270,11 +274,13 @@ public class GenericTableMetaDataProvider implements TableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		return catalogNameToUse(catalogName);
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		if (schemaName == null) {
 			return schemaNameToUse(getDefaultSchema());
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleCallMetaDataProvider.java
index 78cec6c5a71..5a6b5d277ac 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleCallMetaDataProvider.java
@@ -58,12 +58,14 @@ public class OracleCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataCatalogNameToUse(@Nullable String catalogName) {
 		// Oracle uses catalog name for package name or an empty string if no package
 		return (catalogName == null ? "" : catalogNameToUse(catalogName));
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		// Use current user schema if no schema specified
 		return (schemaName == null ? getUserName() : super.metaDataSchemaNameToUse(schemaName));
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleTableMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleTableMetaDataProvider.java
index 6f20d85c736..0cd2419f949 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleTableMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/OracleTableMetaDataProvider.java
@@ -95,6 +95,7 @@ public class OracleTableMetaDataProvider extends GenericTableMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	protected String getDefaultSchema() {
 		if (this.defaultSchema != null) {
 			return defaultSchema;
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/PostgresCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/PostgresCallMetaDataProvider.java
index 0388f795152..b87f98346de 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/PostgresCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/PostgresCallMetaDataProvider.java
@@ -58,6 +58,7 @@ public class PostgresCallMetaDataProvider extends GenericCallMetaDataProvider {
 	}
 
 	@Override
+	@Nullable
 	public String metaDataSchemaNameToUse(@Nullable String schemaName) {
 		// Use public schema if no schema specified
 		return (schemaName == null ? "public" : super.metaDataSchemaNameToUse(schemaName));
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SqlServerCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SqlServerCallMetaDataProvider.java
index e9b2dde324c..67cae69dd31 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SqlServerCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SqlServerCallMetaDataProvider.java
@@ -41,6 +41,7 @@ public class SqlServerCallMetaDataProvider extends GenericCallMetaDataProvider {
 
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SybaseCallMetaDataProvider.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SybaseCallMetaDataProvider.java
index 0c5c0a1acb8..4f5ab456386 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SybaseCallMetaDataProvider.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/SybaseCallMetaDataProvider.java
@@ -41,6 +41,7 @@ public class SybaseCallMetaDataProvider extends GenericCallMetaDataProvider {
 
 
 	@Override
+	@Nullable
 	public String parameterNameToUse(@Nullable String parameterName) {
 		if (parameterName == null) {
 			return null;
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/AbstractSqlParameterSource.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/AbstractSqlParameterSource.java
index 626cfb5f078..34eaa7fd1e6 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/AbstractSqlParameterSource.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/AbstractSqlParameterSource.java
@@ -19,6 +19,7 @@ package org.springframework.jdbc.core.namedparam;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -74,6 +75,7 @@ public abstract class AbstractSqlParameterSource implements SqlParameterSource {
 	 * or {@code null} if not registered
 	 */
 	@Override
+	@Nullable
 	public String getTypeName(String paramName) {
 		Assert.notNull(paramName, "Parameter name must not be null");
 		return this.typeNames.get(paramName);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/BeanPropertySqlParameterSource.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/BeanPropertySqlParameterSource.java
index 5c3bc9ad5bf..bd345c9e71c 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/BeanPropertySqlParameterSource.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/BeanPropertySqlParameterSource.java
@@ -63,6 +63,7 @@ public class BeanPropertySqlParameterSource extends AbstractSqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) throws IllegalArgumentException {
 		try {
 			return this.beanWrapper.getPropertyValue(paramName);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/EmptySqlParameterSource.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/EmptySqlParameterSource.java
index e90d4085954..7a25fd0d3c4 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/EmptySqlParameterSource.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/EmptySqlParameterSource.java
@@ -16,6 +16,8 @@
 
 package org.springframework.jdbc.core.namedparam;
 
+import org.springframework.lang.Nullable;
+
 /**
  * A simple empty implementation of the {@link SqlParameterSource} interface.
  *
@@ -36,6 +38,7 @@ public class EmptySqlParameterSource implements SqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) throws IllegalArgumentException {
 		throw new IllegalArgumentException("This SqlParameterSource is empty");
 	}
@@ -46,6 +49,7 @@ public class EmptySqlParameterSource implements SqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public String getTypeName(String paramName) {
 		return null;
 	}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/MapSqlParameterSource.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/MapSqlParameterSource.java
index a411557bc80..29300163f72 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/MapSqlParameterSource.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/MapSqlParameterSource.java
@@ -155,6 +155,7 @@ public class MapSqlParameterSource extends AbstractSqlParameterSource {
 	}
 
 	@Override
+	@Nullable
 	public Object getValue(String paramName) {
 		if (!hasValue(paramName)) {
 			throw new IllegalArgumentException("No value registered for key '" + paramName + "'");
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java
index afd50732be7..176aed75135 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java
@@ -239,6 +239,7 @@ public interface NamedParameterJdbcOperations {
 	 * one column in that row
 	 * @throws org.springframework.dao.DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
@@ -256,6 +257,7 @@ public interface NamedParameterJdbcOperations {
 	 * one column in that row
 	 * @throws org.springframework.dao.DataAccessException if the query fails
 	 */
+	@Nullable
 	<T> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T> rowMapper)
 			throws DataAccessException;
 
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java
index f2b7c346d21..f66cc650331 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java
@@ -130,6 +130,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, SqlParameterSource paramSource, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -137,6 +138,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, Map<String, ?> paramMap, PreparedStatementCallback<T> action)
 			throws DataAccessException {
 
@@ -144,11 +146,13 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {
 		return execute(sql, EmptySqlParameterSource.INSTANCE, action);
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, SqlParameterSource paramSource, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
@@ -156,6 +160,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, Map<String, ?> paramMap, ResultSetExtractor<T> rse)
 			throws DataAccessException {
 
@@ -163,6 +168,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
 		return query(sql, EmptySqlParameterSource.INSTANCE, rse);
 	}
@@ -206,6 +212,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, SqlParameterSource paramSource, RowMapper<T> rowMapper)
 			throws DataAccessException {
 
@@ -214,6 +221,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Map<String, ?> paramMap, RowMapper<T>rowMapper)
 			throws DataAccessException {
 
@@ -221,6 +229,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, SqlParameterSource paramSource, Class<T> requiredType)
 			throws DataAccessException {
 
@@ -228,6 +237,7 @@ public class NamedParameterJdbcTemplate implements NamedParameterJdbcOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T queryForObject(String sql, Map<String, ?> paramMap, Class<T> requiredType)
 			throws DataAccessException {
 
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/core/support/AbstractLobStreamingResultSetExtractor.java b/spring-jdbc/src/main/java/org/springframework/jdbc/core/support/AbstractLobStreamingResultSetExtractor.java
index 496bbdbfbe9..3883be19f6e 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/core/support/AbstractLobStreamingResultSetExtractor.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/core/support/AbstractLobStreamingResultSetExtractor.java
@@ -25,6 +25,7 @@ import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.jdbc.LobRetrievalFailureException;
 import org.springframework.jdbc.core.ResultSetExtractor;
+import org.springframework.lang.Nullable;
 
 /**
  * Abstract ResultSetExtractor implementation that assumes streaming of LOB data.
@@ -65,6 +66,7 @@ public abstract class AbstractLobStreamingResultSetExtractor<T> implements Resul
 	 * @see org.springframework.jdbc.LobRetrievalFailureException
 	 */
 	@Override
+	@Nullable
 	public final T extractData(ResultSet rs) throws SQLException, DataAccessException {
 		if (!rs.next()) {
 			handleNoRowFound();
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/embedded/EmbeddedDatabaseFactoryBean.java b/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/embedded/EmbeddedDatabaseFactoryBean.java
index d754f435f21..b25180340e4 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/embedded/EmbeddedDatabaseFactoryBean.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/embedded/EmbeddedDatabaseFactoryBean.java
@@ -66,6 +66,7 @@ public class EmbeddedDatabaseFactoryBean extends EmbeddedDatabaseFactory
 
 
 	@Override
+	@Nullable
 	public DataSource getObject() {
 		return getDataSource();
 	}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/lookup/IsolationLevelDataSourceRouter.java b/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/lookup/IsolationLevelDataSourceRouter.java
index 63bb1b66f93..db5a592ab11 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/lookup/IsolationLevelDataSourceRouter.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/datasource/lookup/IsolationLevelDataSourceRouter.java
@@ -17,6 +17,7 @@
 package org.springframework.jdbc.datasource.lookup;
 
 import org.springframework.core.Constants;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.support.DefaultTransactionDefinition;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
@@ -119,6 +120,7 @@ public class IsolationLevelDataSourceRouter extends AbstractRoutingDataSource {
 	}
 
 	@Override
+	@Nullable
 	protected Object determineCurrentLookupKey() {
 		return TransactionSynchronizationManager.getCurrentTransactionIsolationLevel();
 	}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQuery.java b/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQuery.java
index 7aa48d82681..7a7aa314223 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQuery.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQuery.java
@@ -61,6 +61,7 @@ public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T
 	 * @see #mapRow(ResultSet, int)
 	 */
 	@Override
+	@Nullable
 	protected final T mapRow(ResultSet rs, int rowNum, @Nullable Object[] parameters, @Nullable Map<?, ?> context)
 			throws SQLException {
 
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQueryWithParameters.java b/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQueryWithParameters.java
index e862042f2d7..a93cfea308e 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQueryWithParameters.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/object/MappingSqlQueryWithParameters.java
@@ -117,6 +117,7 @@ public abstract class MappingSqlQueryWithParameters<T> extends SqlQuery<T> {
 		}
 
 		@Override
+		@Nullable
 		public T mapRow(ResultSet rs, int rowNum) throws SQLException {
 			return MappingSqlQueryWithParameters.this.mapRow(rs, rowNum, this.params, this.context);
 		}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlFunction.java b/spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlFunction.java
index cf0deb8bd8a..4e78ecfb1c5 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlFunction.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/object/SqlFunction.java
@@ -127,6 +127,7 @@ public class SqlFunction<T> extends MappingSqlQuery<T> {
 	 * of rows returned, this is treated as an error.
 	 */
 	@Override
+	@Nullable
 	protected T mapRow(ResultSet rs, int rowNum) throws SQLException {
 		return this.rowMapper.mapRow(rs, rowNum);
 	}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/AbstractFallbackSQLExceptionTranslator.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/AbstractFallbackSQLExceptionTranslator.java
index b231cd667e4..cc198cf0d1e 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/AbstractFallbackSQLExceptionTranslator.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/AbstractFallbackSQLExceptionTranslator.java
@@ -64,6 +64,7 @@ public abstract class AbstractFallbackSQLExceptionTranslator implements SQLExcep
 	 * {@link #getFallbackTranslator() fallback translator} if necessary.
 	 */
 	@Override
+	@Nullable
 	public DataAccessException translate(@Nullable String task, @Nullable String sql, SQLException ex) {
 		Assert.notNull(ex, "Cannot translate a null SQLException");
 		if (task == null) {
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/GeneratedKeyHolder.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/GeneratedKeyHolder.java
index 0de3fcfc43d..d7f8df8fd53 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/GeneratedKeyHolder.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/GeneratedKeyHolder.java
@@ -23,6 +23,7 @@ import java.util.Map;
 
 import org.springframework.dao.DataRetrievalFailureException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.lang.Nullable;
 
 /**
  * Default implementation of the {@link KeyHolder} interface, to be used for
@@ -58,6 +59,7 @@ public class GeneratedKeyHolder implements KeyHolder {
 
 
 	@Override
+	@Nullable
 	public Number getKey() throws InvalidDataAccessApiUsageException, DataRetrievalFailureException {
 		if (this.keyList.size() == 0) {
 			return null;
@@ -85,6 +87,7 @@ public class GeneratedKeyHolder implements KeyHolder {
 	}
 
 	@Override
+	@Nullable
 	public Map<String, Object> getKeys() throws InvalidDataAccessApiUsageException {
 		if (this.keyList.size() == 0) {
 			return null;
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodeSQLExceptionTranslator.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodeSQLExceptionTranslator.java
index 087a8441b6a..114fc5e7acb 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodeSQLExceptionTranslator.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLErrorCodeSQLExceptionTranslator.java
@@ -168,6 +168,7 @@ public class SQLErrorCodeSQLExceptionTranslator extends AbstractFallbackSQLExcep
 
 
 	@Override
+	@Nullable
 	protected DataAccessException doTranslate(String task, String sql, SQLException ex) {
 		SQLException sqlEx = ex;
 		if (sqlEx instanceof BatchUpdateException && sqlEx.getNextException() != null) {
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLStateSQLExceptionTranslator.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLStateSQLExceptionTranslator.java
index 0c4db4cc739..eb3939a2dd1 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLStateSQLExceptionTranslator.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/SQLStateSQLExceptionTranslator.java
@@ -88,6 +88,7 @@ public class SQLStateSQLExceptionTranslator extends AbstractFallbackSQLException
 
 
 	@Override
+	@Nullable
 	protected DataAccessException doTranslate(String task, String sql, SQLException ex) {
 		// First, the getSQLState check...
 		String sqlState = getSqlState(ex);
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/AbstractLobHandler.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/AbstractLobHandler.java
index 2caea6f2870..6ee0758b634 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/AbstractLobHandler.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/AbstractLobHandler.java
@@ -21,6 +21,8 @@ import java.io.Reader;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Abstract base class for {@link LobHandler} implementations.
  *
@@ -34,21 +36,25 @@ import java.sql.SQLException;
 public abstract class AbstractLobHandler implements LobHandler {
 
 	@Override
+	@Nullable
 	public byte[] getBlobAsBytes(ResultSet rs, String columnName) throws SQLException {
 		return getBlobAsBytes(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public InputStream getBlobAsBinaryStream(ResultSet rs, String columnName) throws SQLException {
 		return getBlobAsBinaryStream(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public String getClobAsString(ResultSet rs, String columnName) throws SQLException {
 		return getClobAsString(rs, rs.findColumn(columnName));
 	}
 
 	@Override
+	@Nullable
 	public InputStream getClobAsAsciiStream(ResultSet rs, String columnName) throws SQLException {
 		return getClobAsAsciiStream(rs, rs.findColumn(columnName));
 	}
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/DefaultLobHandler.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/DefaultLobHandler.java
index 21e5aee67cb..cf8d6d5ae73 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/DefaultLobHandler.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/DefaultLobHandler.java
@@ -148,6 +148,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 
 
 	@Override
+	@Nullable
 	public byte[] getBlobAsBytes(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning BLOB as bytes");
 		if (this.wrapAsLob) {
@@ -160,6 +161,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 	}
 
 	@Override
+	@Nullable
 	public InputStream getBlobAsBinaryStream(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning BLOB as binary stream");
 		if (this.wrapAsLob) {
@@ -172,6 +174,7 @@ public class DefaultLobHandler extends AbstractLobHandler {
 	}
 
 	@Override
+	@Nullable
 	public String getClobAsString(ResultSet rs, int columnIndex) throws SQLException {
 		logger.debug("Returning CLOB as string");
 		if (this.wrapAsLob) {
diff --git a/spring-jdbc/src/main/java/org/springframework/jdbc/support/xml/Jdbc4SqlXmlHandler.java b/spring-jdbc/src/main/java/org/springframework/jdbc/support/xml/Jdbc4SqlXmlHandler.java
index 023c0d93210..f3a2f6aef0a 100644
--- a/spring-jdbc/src/main/java/org/springframework/jdbc/support/xml/Jdbc4SqlXmlHandler.java
+++ b/spring-jdbc/src/main/java/org/springframework/jdbc/support/xml/Jdbc4SqlXmlHandler.java
@@ -53,42 +53,49 @@ public class Jdbc4SqlXmlHandler implements SqlXmlHandler {
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public String getXmlAsString(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getString() : null);
 	}
 
 	@Override
+	@Nullable
 	public String getXmlAsString(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getString() : null);
 	}
 
 	@Override
+	@Nullable
 	public InputStream getXmlAsBinaryStream(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getBinaryStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public InputStream getXmlAsBinaryStream(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getBinaryStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Reader getXmlAsCharacterStream(ResultSet rs, String columnName) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnName);
 		return (xmlObject != null ? xmlObject.getCharacterStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Reader getXmlAsCharacterStream(ResultSet rs, int columnIndex) throws SQLException {
 		SQLXML xmlObject = rs.getSQLXML(columnIndex);
 		return (xmlObject != null ? xmlObject.getCharacterStream() : null);
 	}
 
 	@Override
+	@Nullable
 	public Source getXmlAsSource(ResultSet rs, String columnName, @Nullable Class<? extends Source> sourceClass)
 			throws SQLException {
 
@@ -100,6 +107,7 @@ public class Jdbc4SqlXmlHandler implements SqlXmlHandler {
 	}
 
 	@Override
+	@Nullable
 	public Source getXmlAsSource(ResultSet rs, int columnIndex, @Nullable Class<? extends Source> sourceClass)
 			throws SQLException {
 
diff --git a/spring-jdbc/src/main/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensions.kt b/spring-jdbc/src/main/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensions.kt
index ca9367ed7ea..639bfac9305 100644
--- a/spring-jdbc/src/main/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensions.kt
+++ b/spring-jdbc/src/main/kotlin/org/springframework/jdbc/core/JdbcOperationsExtensions.kt
@@ -33,7 +33,7 @@ inline fun <reified T : Any> JdbcOperations.queryForObject(sql: String): T? = qu
  * @author Mario Arias
  * @since 5.0
  */
-fun <T : Any> JdbcOperations.queryForObject(sql: String, vararg args: Any, function: (ResultSet, Int) -> T): T =
+fun <T : Any> JdbcOperations.queryForObject(sql: String, vararg args: Any, function: (ResultSet, Int) -> T): T? =
 		queryForObject(sql, RowMapper { resultSet, i -> function(resultSet, i) }, *args)
 
 /**
diff --git a/spring-jms/src/main/java/org/springframework/jms/JmsException.java b/spring-jms/src/main/java/org/springframework/jms/JmsException.java
index eb656a003f6..2da3fff739b 100644
--- a/spring-jms/src/main/java/org/springframework/jms/JmsException.java
+++ b/spring-jms/src/main/java/org/springframework/jms/JmsException.java
@@ -83,6 +83,7 @@ public abstract class JmsException extends NestedRuntimeException {
 	 * @see javax.jms.JMSException#getLinkedException()
 	 */
 	@Override
+	@Nullable
 	public String getMessage() {
 		String message = super.getMessage();
 		Throwable cause = getCause();
diff --git a/spring-jms/src/main/java/org/springframework/jms/config/AbstractListenerContainerParser.java b/spring-jms/src/main/java/org/springframework/jms/config/AbstractListenerContainerParser.java
index 0af4bbb845c..db1388326a6 100644
--- a/spring-jms/src/main/java/org/springframework/jms/config/AbstractListenerContainerParser.java
+++ b/spring-jms/src/main/java/org/springframework/jms/config/AbstractListenerContainerParser.java
@@ -103,6 +103,7 @@ abstract class AbstractListenerContainerParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		CompositeComponentDefinition compositeDef =
 				new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
diff --git a/spring-jms/src/main/java/org/springframework/jms/config/AnnotationDrivenJmsBeanDefinitionParser.java b/spring-jms/src/main/java/org/springframework/jms/config/AnnotationDrivenJmsBeanDefinitionParser.java
index 5bec66d4808..b5a4bb93c19 100644
--- a/spring-jms/src/main/java/org/springframework/jms/config/AnnotationDrivenJmsBeanDefinitionParser.java
+++ b/spring-jms/src/main/java/org/springframework/jms/config/AnnotationDrivenJmsBeanDefinitionParser.java
@@ -38,6 +38,7 @@ import org.springframework.util.StringUtils;
 class AnnotationDrivenJmsBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);
 
diff --git a/spring-jms/src/main/java/org/springframework/jms/connection/ConnectionFactoryUtils.java b/spring-jms/src/main/java/org/springframework/jms/connection/ConnectionFactoryUtils.java
index 84bc69983f0..ba7d9bfeef3 100644
--- a/spring-jms/src/main/java/org/springframework/jms/connection/ConnectionFactoryUtils.java
+++ b/spring-jms/src/main/java/org/springframework/jms/connection/ConnectionFactoryUtils.java
@@ -139,10 +139,12 @@ public abstract class ConnectionFactoryUtils {
 
 		return doGetTransactionalSession(cf, new ResourceFactory() {
 			@Override
+			@Nullable
 			public Session getSession(JmsResourceHolder holder) {
 				return holder.getSession(Session.class, existingCon);
 			}
 			@Override
+			@Nullable
 			public Connection getConnection(JmsResourceHolder holder) {
 				return (existingCon != null ? existingCon : holder.getConnection());
 			}
@@ -182,10 +184,12 @@ public abstract class ConnectionFactoryUtils {
 
 		return (QueueSession) doGetTransactionalSession(cf, new ResourceFactory() {
 			@Override
+			@Nullable
 			public Session getSession(JmsResourceHolder holder) {
 				return holder.getSession(QueueSession.class, existingCon);
 			}
 			@Override
+			@Nullable
 			public Connection getConnection(JmsResourceHolder holder) {
 				return (existingCon != null ? existingCon : holder.getConnection(QueueConnection.class));
 			}
@@ -225,10 +229,12 @@ public abstract class ConnectionFactoryUtils {
 
 		return (TopicSession) doGetTransactionalSession(cf, new ResourceFactory() {
 			@Override
+			@Nullable
 			public Session getSession(JmsResourceHolder holder) {
 				return holder.getSession(TopicSession.class, existingCon);
 			}
 			@Override
+			@Nullable
 			public Connection getConnection(JmsResourceHolder holder) {
 				return (existingCon != null ? existingCon : holder.getConnection(TopicConnection.class));
 			}
diff --git a/spring-jms/src/main/java/org/springframework/jms/core/JmsMessagingTemplate.java b/spring-jms/src/main/java/org/springframework/jms/core/JmsMessagingTemplate.java
index 4785a1795d1..8dc19c14d4f 100644
--- a/spring-jms/src/main/java/org/springframework/jms/core/JmsMessagingTemplate.java
+++ b/spring-jms/src/main/java/org/springframework/jms/core/JmsMessagingTemplate.java
@@ -230,6 +230,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public Message<?> receive() {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -241,6 +242,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public <T> T receiveAndConvert(Class<T> targetClass) {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -252,11 +254,13 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public Message<?> receive(String destinationName) throws MessagingException {
 		return doReceive(destinationName);
 	}
 
 	@Override
+	@Nullable
 	public <T> T receiveAndConvert(String destinationName, Class<T> targetClass) throws MessagingException {
 		Message<?> message = doReceive(destinationName);
 		if (message != null) {
@@ -268,6 +272,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public Message<?> sendAndReceive(Message<?> requestMessage) {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -279,11 +284,13 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public Message<?> sendAndReceive(String destinationName, Message<?> requestMessage) throws MessagingException {
 		return doSendAndReceive(destinationName, requestMessage);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request, Class<T> targetClass)
 			throws MessagingException {
 
@@ -291,11 +298,13 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(Object request, Class<T> targetClass) {
 		return convertSendAndReceive(request, targetClass, null);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request,
 			@Nullable Map<String, Object> headers, Class<T> targetClass) throws MessagingException {
 
@@ -303,6 +312,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(Object request, Class<T> targetClass, @Nullable MessagePostProcessor postProcessor) {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -314,6 +324,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request, Class<T> targetClass,
 			@Nullable MessagePostProcessor requestPostProcessor) throws MessagingException {
 
@@ -322,6 +333,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request, @Nullable Map<String, Object> headers,
 			Class<T> targetClass, @Nullable MessagePostProcessor postProcessor) {
 
@@ -350,6 +362,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	protected Message<?> doReceive(Destination destination) {
 		try {
 			javax.jms.Message jmsMessage = obtainJmsTemplate().receive(destination);
@@ -372,6 +385,7 @@ public class JmsMessagingTemplate extends AbstractMessagingTemplate<Destination>
 	}
 
 	@Override
+	@Nullable
 	protected Message<?> doSendAndReceive(Destination destination, Message<?> requestMessage) {
 		try {
 			javax.jms.Message jmsMessage = obtainJmsTemplate().sendAndReceive(
diff --git a/spring-jms/src/main/java/org/springframework/jms/core/JmsTemplate.java b/spring-jms/src/main/java/org/springframework/jms/core/JmsTemplate.java
index 794c5bc99a7..02397ef7610 100644
--- a/spring-jms/src/main/java/org/springframework/jms/core/JmsTemplate.java
+++ b/spring-jms/src/main/java/org/springframework/jms/core/JmsTemplate.java
@@ -463,6 +463,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	//---------------------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T execute(SessionCallback<T> action) throws JmsException {
 		return execute(action, false);
 	}
@@ -512,6 +513,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(ProducerCallback<T> action) throws JmsException {
 		String defaultDestinationName = getDefaultDestinationName();
 		if (defaultDestinationName != null) {
@@ -523,6 +525,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(final @Nullable Destination destination, final ProducerCallback<T> action) throws JmsException {
 		Assert.notNull(action, "Callback object must not be null");
 		return execute(session -> {
@@ -537,6 +540,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(final String destinationName, final ProducerCallback<T> action) throws JmsException {
 		Assert.notNull(action, "Callback object must not be null");
 		return execute(session -> {
@@ -700,6 +704,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	//---------------------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public Message receive() throws JmsException {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -711,16 +716,19 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public Message receive(Destination destination) throws JmsException {
 		return receiveSelected(destination, null);
 	}
 
 	@Override
+	@Nullable
 	public Message receive(String destinationName) throws JmsException {
 		return receiveSelected(destinationName, null);
 	}
 
-	@Override
+	@Override@Nullable
+	
 	public Message receiveSelected(String messageSelector) throws JmsException {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -732,6 +740,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public Message receiveSelected(final Destination destination, @Nullable final String messageSelector) throws JmsException {
 		return execute(session -> {
 			return doReceive(session, destination, messageSelector);
@@ -739,6 +748,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public Message receiveSelected(final String destinationName, @Nullable final String messageSelector) throws JmsException {
 		return execute(session -> {
 			Destination destination = resolveDestinationName(session, destinationName);
@@ -808,31 +818,37 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	//---------------------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public Object receiveAndConvert() throws JmsException {
 		return doConvertFromMessage(receive());
 	}
 
 	@Override
+	@Nullable
 	public Object receiveAndConvert(Destination destination) throws JmsException {
 		return doConvertFromMessage(receive(destination));
 	}
 
 	@Override
+	@Nullable
 	public Object receiveAndConvert(String destinationName) throws JmsException {
 		return doConvertFromMessage(receive(destinationName));
 	}
 
 	@Override
+	@Nullable
 	public Object receiveSelectedAndConvert(String messageSelector) throws JmsException {
 		return doConvertFromMessage(receiveSelected(messageSelector));
 	}
 
 	@Override
+	@Nullable
 	public Object receiveSelectedAndConvert(Destination destination, String messageSelector) throws JmsException {
 		return doConvertFromMessage(receiveSelected(destination, messageSelector));
 	}
 
 	@Override
+	@Nullable
 	public Object receiveSelectedAndConvert(String destinationName, String messageSelector) throws JmsException {
 		return doConvertFromMessage(receiveSelected(destinationName, messageSelector));
 	}
@@ -861,6 +877,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	//---------------------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public Message sendAndReceive(MessageCreator messageCreator) throws JmsException {
 		Destination defaultDestination = getDefaultDestination();
 		if (defaultDestination != null) {
@@ -872,11 +889,13 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public Message sendAndReceive(final Destination destination, final MessageCreator messageCreator) throws JmsException {
 		return executeLocal(session -> doSendAndReceive(session, destination, messageCreator), true);
 	}
 
 	@Override
+	@Nullable
 	public Message sendAndReceive(final String destinationName, final MessageCreator messageCreator) throws JmsException {
 		return executeLocal(session -> {
 			Destination destination = resolveDestinationName(session, destinationName);
@@ -955,6 +974,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	//---------------------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T browse(BrowserCallback<T> action) throws JmsException {
 		Queue defaultQueue = getDefaultQueue();
 		if (defaultQueue != null) {
@@ -966,16 +986,19 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T browse(Queue queue, BrowserCallback<T> action) throws JmsException {
 		return browseSelected(queue, null, action);
 	}
 
 	@Override
+	@Nullable
 	public <T> T browse(String queueName, BrowserCallback<T> action) throws JmsException {
 		return browseSelected(queueName, null, action);
 	}
 
 	@Override
+	@Nullable
 	public <T> T browseSelected(String messageSelector, BrowserCallback<T> action) throws JmsException {
 		Queue defaultQueue = getDefaultQueue();
 		if (defaultQueue != null) {
@@ -987,6 +1010,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T browseSelected(final Queue queue, @Nullable final String messageSelector, final BrowserCallback<T> action)
 			throws JmsException {
 
@@ -1003,6 +1027,7 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	}
 
 	@Override
+	@Nullable
 	public <T> T browseSelected(final String queueName, @Nullable final String messageSelector, final BrowserCallback<T> action)
 			throws JmsException {
 
@@ -1145,11 +1170,13 @@ public class JmsTemplate extends JmsDestinationAccessor implements JmsOperations
 	private class JmsTemplateResourceFactory implements ConnectionFactoryUtils.ResourceFactory {
 
 		@Override
+		@Nullable
 		public Connection getConnection(JmsResourceHolder holder) {
 			return JmsTemplate.this.getConnection(holder);
 		}
 
 		@Override
+		@Nullable
 		public Session getSession(JmsResourceHolder holder) {
 			return JmsTemplate.this.getSession(holder);
 		}
diff --git a/spring-jms/src/main/java/org/springframework/jms/listener/AbstractPollingMessageListenerContainer.java b/spring-jms/src/main/java/org/springframework/jms/listener/AbstractPollingMessageListenerContainer.java
index 555522b04ec..ca216377ddd 100644
--- a/spring-jms/src/main/java/org/springframework/jms/listener/AbstractPollingMessageListenerContainer.java
+++ b/spring-jms/src/main/java/org/springframework/jms/listener/AbstractPollingMessageListenerContainer.java
@@ -469,11 +469,13 @@ public abstract class AbstractPollingMessageListenerContainer extends AbstractMe
 	private class MessageListenerContainerResourceFactory implements ConnectionFactoryUtils.ResourceFactory {
 
 		@Override
+		@Nullable
 		public Connection getConnection(JmsResourceHolder holder) {
 			return AbstractPollingMessageListenerContainer.this.getConnection(holder);
 		}
 
 		@Override
+		@Nullable
 		public Session getSession(JmsResourceHolder holder) {
 			return AbstractPollingMessageListenerContainer.this.getSession(holder);
 		}
diff --git a/spring-jms/src/main/java/org/springframework/jms/listener/adapter/MessageListenerAdapter.java b/spring-jms/src/main/java/org/springframework/jms/listener/adapter/MessageListenerAdapter.java
index 9da2823f408..ff44538b8ca 100644
--- a/spring-jms/src/main/java/org/springframework/jms/listener/adapter/MessageListenerAdapter.java
+++ b/spring-jms/src/main/java/org/springframework/jms/listener/adapter/MessageListenerAdapter.java
@@ -256,7 +256,6 @@ public class MessageListenerAdapter extends AbstractAdaptableMessageListener imp
 	 * @throws JMSException if thrown by JMS API methods
 	 * @see #setDefaultListenerMethod
 	 */
-	@Nullable
 	protected String getListenerMethodName(Message originalMessage, Object extractedMessage) throws JMSException {
 		return getDefaultListenerMethod();
 	}
diff --git a/spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsMessageEndpointManager.java b/spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsMessageEndpointManager.java
index a8a255b3b5b..7cf83d25ad6 100644
--- a/spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsMessageEndpointManager.java
+++ b/spring-jms/src/main/java/org/springframework/jms/listener/endpoint/JmsMessageEndpointManager.java
@@ -191,6 +191,7 @@ public class JmsMessageEndpointManager extends GenericMessageEndpointManager
 	}
 
 	@Override
+	@Nullable
 	public MessageConverter getMessageConverter() {
 		JmsActivationSpecConfig config = getActivationSpecConfig();
 		if (config != null) {
@@ -200,6 +201,7 @@ public class JmsMessageEndpointManager extends GenericMessageEndpointManager
 	}
 
 	@Override
+	@Nullable
 	public DestinationResolver getDestinationResolver() {
 		if (this.activationSpecFactory instanceof StandardJmsActivationSpecFactory) {
 			return ((StandardJmsActivationSpecFactory) this.activationSpecFactory).getDestinationResolver();
@@ -226,6 +228,7 @@ public class JmsMessageEndpointManager extends GenericMessageEndpointManager
 	}
 
 	@Override
+	@Nullable
 	public QosSettings getReplyQosSettings() {
 		JmsActivationSpecConfig config = getActivationSpecConfig();
 		if (config != null) {
diff --git a/spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerProxyFactoryBean.java b/spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerProxyFactoryBean.java
index 6b0f7630f68..b49130fa2ee 100644
--- a/spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerProxyFactoryBean.java
+++ b/spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerProxyFactoryBean.java
@@ -81,6 +81,7 @@ public class JmsInvokerProxyFactoryBean extends JmsInvokerClientInterceptor
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.serviceProxy;
 	}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java
index 7be22682422..4e7379f252b 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java
@@ -167,11 +167,13 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 	}
 
 	@Override
+	@Nullable
 	public final Object fromMessage(Message<?> message, Class<?> targetClass) {
 		return fromMessage(message, targetClass, null);
 	}
 
 	@Override
+	@Nullable
 	public final Object fromMessage(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
 		if (!canConvertFrom(message, targetClass)) {
 			return null;
@@ -184,11 +186,13 @@ public abstract class AbstractMessageConverter implements SmartMessageConverter
 	}
 
 	@Override
+	@Nullable
 	public final Message<?> toMessage(Object payload, @Nullable MessageHeaders headers) {
 		return toMessage(payload, headers, null);
 	}
 
 	@Override
+	@Nullable
 	public final Message<?> toMessage(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
 		if (!canConvertTo(payload, headers)) {
 			return null;
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/CompositeMessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/CompositeMessageConverter.java
index 30832f86d32..08309ac563b 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/CompositeMessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/CompositeMessageConverter.java
@@ -51,6 +51,7 @@ public class CompositeMessageConverter implements SmartMessageConverter {
 
 
 	@Override
+	@Nullable
 	public Object fromMessage(Message<?> message, Class<?> targetClass) {
 		for (MessageConverter converter : getConverters()) {
 			Object result = converter.fromMessage(message, targetClass);
@@ -62,6 +63,7 @@ public class CompositeMessageConverter implements SmartMessageConverter {
 	}
 
 	@Override
+	@Nullable
 	public Object fromMessage(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
 		for (MessageConverter converter : getConverters()) {
 			Object result = (converter instanceof SmartMessageConverter ?
@@ -75,6 +77,7 @@ public class CompositeMessageConverter implements SmartMessageConverter {
 	}
 
 	@Override
+	@Nullable
 	public Message<?> toMessage(Object payload, @Nullable MessageHeaders headers) {
 		for (MessageConverter converter : getConverters()) {
 			Message<?> result = converter.toMessage(payload, headers);
@@ -86,6 +89,7 @@ public class CompositeMessageConverter implements SmartMessageConverter {
 	}
 
 	@Override
+	@Nullable
 	public Message<?> toMessage(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
 		for (MessageConverter converter : getConverters()) {
 			Message<?> result = (converter instanceof SmartMessageConverter ?
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/DefaultContentTypeResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/DefaultContentTypeResolver.java
index 0415a72b89b..5d6a10008f6 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/DefaultContentTypeResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/DefaultContentTypeResolver.java
@@ -56,6 +56,7 @@ public class DefaultContentTypeResolver implements ContentTypeResolver {
 
 
 	@Override
+	@Nullable
 	public MimeType resolve(@Nullable MessageHeaders headers) {
 		if (headers == null || headers.get(MessageHeaders.CONTENT_TYPE) == null) {
 			return this.defaultMimeType;
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/GenericMessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/GenericMessageConverter.java
index 858ce2d0417..2b369e98b1c 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/GenericMessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/GenericMessageConverter.java
@@ -19,6 +19,7 @@ package org.springframework.messaging.converter;
 import org.springframework.core.convert.ConversionException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -57,6 +58,7 @@ public class GenericMessageConverter extends SimpleMessageConverter {
 
 
 	@Override
+	@Nullable
 	public Object fromMessage(Message<?> message, Class<?> targetClass) {
 		Object payload = message.getPayload();
 		if (this.conversionService.canConvert(payload.getClass(), targetClass)) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java
index 9bba9b244c3..e29834a02c2 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/MappingJackson2MessageConverter.java
@@ -205,6 +205,7 @@ public class MappingJackson2MessageConverter extends AbstractMessageConverter {
 	}
 
 	@Override
+	@Nullable
 	protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
 		JavaType javaType = this.objectMapper.constructType(targetClass);
 		Object payload = message.getPayload();
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/SimpleMessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/SimpleMessageConverter.java
index e654a3590aa..7ec8bcc13ef 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/SimpleMessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/SimpleMessageConverter.java
@@ -36,6 +36,7 @@ import org.springframework.util.ClassUtils;
 public class SimpleMessageConverter implements MessageConverter {
 
 	@Override
+	@Nullable
 	public Object fromMessage(Message<?> message, Class<?> targetClass) {
 		Object payload = message.getPayload();
 		return (ClassUtils.isAssignableValue(targetClass, payload) ? payload : null);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/converter/StringMessageConverter.java b/spring-messaging/src/main/java/org/springframework/messaging/converter/StringMessageConverter.java
index 48b5c0907a6..3798bf3ffb5 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/converter/StringMessageConverter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/converter/StringMessageConverter.java
@@ -61,6 +61,7 @@ public class StringMessageConverter extends AbstractMessageConverter {
 	}
 
 	@Override
+	@Nullable
 	protected Object convertToInternal(
 			Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint) {
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractDestinationResolvingMessagingTemplate.java b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractDestinationResolvingMessagingTemplate.java
index e2bdb367fcb..b06d8daad6c 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractDestinationResolvingMessagingTemplate.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractDestinationResolvingMessagingTemplate.java
@@ -100,30 +100,35 @@ public abstract class AbstractDestinationResolvingMessagingTemplate<D> extends A
 	}
 
 	@Override
+	@Nullable
 	public Message<?> receive(String destinationName) {
 		D destination = resolveDestination(destinationName);
 		return super.receive(destination);
 	}
 
 	@Override
+	@Nullable
 	public <T> T receiveAndConvert(String destinationName, Class<T> targetClass) {
 		D destination = resolveDestination(destinationName);
 		return super.receiveAndConvert(destination, targetClass);
 	}
 
 	@Override
+	@Nullable
 	public Message<?> sendAndReceive(String destinationName, Message<?> requestMessage) {
 		D destination = resolveDestination(destinationName);
 		return super.sendAndReceive(destination, requestMessage);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request, Class<T> targetClass) {
 		D destination = resolveDestination(destinationName);
 		return super.convertSendAndReceive(destination, request, targetClass);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request,
 			@Nullable Map<String, Object> headers, Class<T> targetClass) {
 
@@ -132,6 +137,7 @@ public abstract class AbstractDestinationResolvingMessagingTemplate<D> extends A
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request, Class<T> targetClass,
 			@Nullable MessagePostProcessor postProcessor) {
 
@@ -140,6 +146,7 @@ public abstract class AbstractDestinationResolvingMessagingTemplate<D> extends A
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(String destinationName, Object request,
 			@Nullable Map<String, Object> headers, Class<T> targetClass,
 			@Nullable MessagePostProcessor postProcessor) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageReceivingTemplate.java b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageReceivingTemplate.java
index 09f757fe089..67ce6af27b8 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageReceivingTemplate.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageReceivingTemplate.java
@@ -34,11 +34,13 @@ public abstract class AbstractMessageReceivingTemplate<D> extends AbstractMessag
 		implements MessageReceivingOperations<D> {
 
 	@Override
+	@Nullable
 	public Message<?> receive() {
 		return doReceive(getRequiredDefaultDestination());
 	}
 
 	@Override
+	@Nullable
 	public Message<?> receive(D destination) {
 		return doReceive(destination);
 	}
@@ -54,11 +56,13 @@ public abstract class AbstractMessageReceivingTemplate<D> extends AbstractMessag
 
 
 	@Override
+	@Nullable
 	public <T> T receiveAndConvert(Class<T> targetClass) {
 		return receiveAndConvert(getRequiredDefaultDestination(), targetClass);
 	}
 
 	@Override
+	@Nullable
 	public <T> T receiveAndConvert(D destination, Class<T> targetClass) {
 		Message<?> message = doReceive(destination);
 		if (message != null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessagingTemplate.java b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessagingTemplate.java
index 6783dfb4d97..f014c234f04 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessagingTemplate.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessagingTemplate.java
@@ -34,11 +34,13 @@ public abstract class AbstractMessagingTemplate<D> extends AbstractMessageReceiv
 		implements MessageRequestReplyOperations<D> {
 
 	@Override
+	@Nullable
 	public Message<?> sendAndReceive(Message<?> requestMessage) {
 		return sendAndReceive(getRequiredDefaultDestination(), requestMessage);
 	}
 
 	@Override
+	@Nullable
 	public Message<?> sendAndReceive(D destination, Message<?> requestMessage) {
 		return doSendAndReceive(destination, requestMessage);
 	}
@@ -48,16 +50,19 @@ public abstract class AbstractMessagingTemplate<D> extends AbstractMessageReceiv
 
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(Object request, Class<T> targetClass) {
 		return convertSendAndReceive(getRequiredDefaultDestination(), request, targetClass);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(D destination, Object request, Class<T> targetClass) {
 		return convertSendAndReceive(destination, request, null, targetClass);
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(
 			D destination, Object request, @Nullable Map<String, Object> headers, Class<T> targetClass) {
 
@@ -65,6 +70,7 @@ public abstract class AbstractMessagingTemplate<D> extends AbstractMessageReceiv
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(
 			Object request, Class<T> targetClass, @Nullable MessagePostProcessor postProcessor) {
 
@@ -72,6 +78,7 @@ public abstract class AbstractMessagingTemplate<D> extends AbstractMessageReceiv
 	}
 
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(D destination, Object request, Class<T> targetClass,
 			@Nullable MessagePostProcessor postProcessor) {
 
@@ -80,6 +87,7 @@ public abstract class AbstractMessagingTemplate<D> extends AbstractMessageReceiv
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T convertSendAndReceive(D destination, Object request, @Nullable Map<String, Object> headers,
 			Class<T> targetClass, @Nullable MessagePostProcessor postProcessor) {
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/core/GenericMessagingTemplate.java b/spring-messaging/src/main/java/org/springframework/messaging/core/GenericMessagingTemplate.java
index b9905766be7..06ba54316f6 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/core/GenericMessagingTemplate.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/core/GenericMessagingTemplate.java
@@ -189,6 +189,7 @@ public class GenericMessagingTemplate extends AbstractDestinationResolvingMessag
 	}
 
 	@Override
+	@Nullable
 	protected final Message<?> doReceive(MessageChannel channel) {
 		return doReceive(channel, this.receiveTimeout);
 	}
@@ -209,6 +210,7 @@ public class GenericMessagingTemplate extends AbstractDestinationResolvingMessag
 	}
 
 	@Override
+	@Nullable
 	protected final Message<?> doSendAndReceive(MessageChannel channel, Message<?> requestMessage) {
 		Assert.notNull(channel, "'channel' is required");
 		Object originalReplyChannelHeader = requestMessage.getHeaders().getReplyChannel();
@@ -294,11 +296,13 @@ public class GenericMessagingTemplate extends AbstractDestinationResolvingMessag
 		}
 
 		@Override
+		@Nullable
 		public Message<?> receive() {
 			return this.receive(-1);
 		}
 
 		@Override
+		@Nullable
 		public Message<?> receive(long timeout) {
 			try {
 				if (timeout < 0) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/DestinationPatternsMessageCondition.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/DestinationPatternsMessageCondition.java
index 289fb73b0e9..3534cafb2ac 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/DestinationPatternsMessageCondition.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/DestinationPatternsMessageCondition.java
@@ -145,6 +145,7 @@ public class DestinationPatternsMessageCondition extends AbstractMessageConditio
 	 * or {@code null} either if a destination can not be extracted or there is no match
 	 */
 	@Override
+	@Nullable
 	public DestinationPatternsMessageCondition getMatchingCondition(Message<?> message) {
 		String destination = (String) message.getHeaders().get(LOOKUP_DESTINATION_HEADER);
 		if (destination == null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java
index 1c460b4bca1..90d46dd06d2 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/AbstractNamedValueMethodArgumentResolver.java
@@ -84,6 +84,7 @@ public abstract class AbstractNamedValueMethodArgumentResolver implements Handle
 
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
 		NamedValueInfo namedValueInfo = getNamedValueInfo(parameter);
 		MethodParameter nestedParameter = parameter.nestedIfOptional();
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/DestinationVariableMethodArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/DestinationVariableMethodArgumentResolver.java
index 76e6a8e1bfa..1291cab2c50 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/DestinationVariableMethodArgumentResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/DestinationVariableMethodArgumentResolver.java
@@ -20,6 +20,7 @@ import java.util.Map;
 
 import org.springframework.core.MethodParameter;
 import org.springframework.core.convert.ConversionService;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHandlingException;
 import org.springframework.messaging.handler.annotation.DestinationVariable;
@@ -55,6 +56,7 @@ public class DestinationVariableMethodArgumentResolver extends AbstractNamedValu
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveArgumentInternal(MethodParameter parameter, Message<?> message, String name)
 			throws Exception {
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolver.java
index a08db6058cf..26a6b842f82 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolver.java
@@ -59,6 +59,7 @@ public class HeaderMethodArgumentResolver extends AbstractNamedValueMethodArgume
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveArgumentInternal(MethodParameter parameter, Message<?> message, String name)
 			throws Exception {
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeadersMethodArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeadersMethodArgumentResolver.java
index 14fcf457214..307a0e8a92c 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeadersMethodArgumentResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/HeadersMethodArgumentResolver.java
@@ -20,6 +20,7 @@ import java.lang.reflect.Method;
 import java.util.Map;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.handler.annotation.Headers;
@@ -50,6 +51,7 @@ public class HeadersMethodArgumentResolver implements HandlerMethodArgumentResol
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
 
 		Class<?> paramType = parameter.getParameterType();
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadArgumentResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadArgumentResolver.java
index df31202e234..022441df4d8 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadArgumentResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadArgumentResolver.java
@@ -105,6 +105,7 @@ public class PayloadArgumentResolver implements HandlerMethodArgumentResolver {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
 		Payload ann = parameter.getParameterAnnotation(Payload.class);
 		if (ann != null && StringUtils.hasText(ann.expression())) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodArgumentResolverComposite.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodArgumentResolverComposite.java
index cd0682b7c58..6a70d1c34a3 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodArgumentResolverComposite.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodArgumentResolverComposite.java
@@ -106,6 +106,7 @@ public class HandlerMethodArgumentResolverComposite implements HandlerMethodArgu
 	 * @exception IllegalStateException if no suitable {@link HandlerMethodArgumentResolver} is found.
 	 */
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
 
 		HandlerMethodArgumentResolver resolver = getArgumentResolver(parameter);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodReturnValueHandlerComposite.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodReturnValueHandlerComposite.java
index 9389d38e7dd..21f779b9726 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodReturnValueHandlerComposite.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/HandlerMethodReturnValueHandlerComposite.java
@@ -115,6 +115,7 @@ public class HandlerMethodReturnValueHandlerComposite implements AsyncHandlerMet
 	}
 
 	@Override
+	@Nullable
 	public ListenableFuture<?> toListenableFuture(Object returnValue, MethodParameter returnType) {
 		HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
 		Assert.state(handler instanceof AsyncHandlerMethodReturnValueHandler,
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageMappingInfo.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageMappingInfo.java
index eca08f96227..ceb0d541759 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageMappingInfo.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageMappingInfo.java
@@ -65,6 +65,7 @@ public class SimpMessageMappingInfo implements MessageCondition<SimpMessageMappi
 	}
 
 	@Override
+	@Nullable
 	public SimpMessageMappingInfo getMatchingCondition(Message<?> message) {
 		SimpMessageTypeMessageCondition typeCond = this.messageTypeMessageCondition.getMatchingCondition(message);
 		if (typeCond == null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageTypeMessageCondition.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageTypeMessageCondition.java
index 9f33e2212da..bcdc4654bb4 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageTypeMessageCondition.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageTypeMessageCondition.java
@@ -19,6 +19,7 @@ package org.springframework.messaging.simp;
 import java.util.Arrays;
 import java.util.Collection;
 
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.handler.AbstractMessageCondition;
 import org.springframework.util.Assert;
@@ -71,6 +72,7 @@ public class SimpMessageTypeMessageCondition extends AbstractMessageCondition<Si
 	}
 
 	@Override
+	@Nullable
 	public SimpMessageTypeMessageCondition getMatchingCondition(Message<?> message) {
 		Object actualMessageType = SimpMessageHeaderAccessor.getMessageType(message.getHeaders());
 		if (actualMessageType == null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpSessionScope.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpSessionScope.java
index 95c8cba664f..cf304368ab4 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpSessionScope.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpSessionScope.java
@@ -18,6 +18,7 @@ package org.springframework.messaging.simp;
 
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.config.Scope;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -51,6 +52,7 @@ public class SimpSessionScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		SimpAttributes simpAttributes = SimpAttributesContextHolder.currentAttributes();
 		synchronized (simpAttributes.getSessionMutex()) {
@@ -71,6 +73,7 @@ public class SimpSessionScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveContextualObject(String key) {
 		return null;
 	}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java
index 068a7b04ee1..2fbc3931902 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SendToMethodReturnValueHandler.java
@@ -285,6 +285,7 @@ public class SendToMethodReturnValueHandler implements HandlerMethodReturnValueH
 		}
 
 		@Override
+		@Nullable
 		public String resolvePlaceholder(String placeholderName) {
 			return (this.vars != null ? this.vars.get(placeholderName) : null);
 		}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java
index 05b1eb7111f..3404de98355 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java
@@ -366,6 +366,7 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 	}
 
 	@Override
+	@Nullable
 	protected SimpMessageMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
 		MessageMapping messageAnn = AnnotatedElementUtils.findMergedAnnotation(method, MessageMapping.class);
 		if (messageAnn != null) {
@@ -438,6 +439,7 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 	}
 
 	@Override
+	@Nullable
 	protected String getDestination(Message<?> message) {
 		return SimpMessageHeaderAccessor.getDestination(message.getHeaders());
 	}
@@ -464,6 +466,7 @@ public class SimpAnnotationMethodMessageHandler extends AbstractMethodMessageHan
 	}
 
 	@Override
+	@Nullable
 	protected SimpMessageMappingInfo getMatchingMapping(SimpMessageMappingInfo mapping, Message<?> message) {
 		return mapping.getMatchingCondition(message);
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/DefaultStompSession.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/DefaultStompSession.java
index 9e2836621df..8dc7c624007 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/DefaultStompSession.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/DefaultStompSession.java
@@ -632,6 +632,7 @@ public class DefaultStompSession implements ConnectionHandlingStompSession {
 		}
 
 		@Override
+		@Nullable
 		public String getSubscriptionId() {
 			return this.headers.getId();
 		}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
index a50f87d79e3..9dc38003786 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
@@ -181,6 +181,8 @@ public class StompHeaderAccessor extends SimpMessageHeaderAccessor {
 	}
 
 	// Redeclared for visibility within simp.stomp
+	@Override
+	@Nullable
 	protected Map<String, List<String>> getNativeHeaders() {
 		return super.getNativeHeaders();
 	}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
index 3993f1a888c..6549e76f740 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
@@ -399,6 +399,7 @@ public class StompHeaders implements MultiValueMap<String, String>, Serializable
 	 * @return the first header value, or {@code null} if none
 	 */
 	@Override
+	@Nullable
 	public String getFirst(String headerName) {
 		List<String> headerValues = headers.get(headerName);
 		return headerValues != null ? headerValues.get(0) : null;
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/user/DefaultUserDestinationResolver.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/user/DefaultUserDestinationResolver.java
index ed141b94477..ce369aa6eaf 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/user/DefaultUserDestinationResolver.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/user/DefaultUserDestinationResolver.java
@@ -120,6 +120,7 @@ public class DefaultUserDestinationResolver implements UserDestinationResolver {
 
 
 	@Override
+	@Nullable
 	public UserDestinationResult resolveDestination(Message<?> message) {
 		ParseResult parseResult = parse(message);
 		if (parseResult == null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/user/MultiServerUserRegistry.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/user/MultiServerUserRegistry.java
index f76ba0c7661..e7744e3e77c 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/user/MultiServerUserRegistry.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/user/MultiServerUserRegistry.java
@@ -115,6 +115,7 @@ public class MultiServerUserRegistry implements SimpUserRegistry, SmartApplicati
 	// SimpUserRegistry methods
 
 	@Override
+	@Nullable
 	public SimpUser getUser(String userName) {
 		// Prefer remote registries due to cross-server SessionLookup
 		for (UserRegistrySnapshot registry : this.remoteRegistries.values()) {
@@ -321,6 +322,7 @@ public class MultiServerUserRegistry implements SimpUserRegistry, SmartApplicati
 		}
 
 		@Override
+		@Nullable
 		public SimpSession getSession(String sessionId) {
 			if (this.sessionLookup != null) {
 				return this.sessionLookup.findSessions(getName()).get(sessionId);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/MonoToListenableFutureAdapter.java b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/MonoToListenableFutureAdapter.java
index 0eb76b88654..698a8edf03d 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/MonoToListenableFutureAdapter.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/MonoToListenableFutureAdapter.java
@@ -35,6 +35,7 @@ class MonoToListenableFutureAdapter<T> extends AbstractMonoToListenableFutureAda
 	}
 
 	@Override
+	@Nullable
 	protected T adapt(@Nullable T result) {
 		return result;
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateExceptionTranslator.java b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateExceptionTranslator.java
index 4e70b21e4fe..ab48f5695ef 100644
--- a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateExceptionTranslator.java
+++ b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateExceptionTranslator.java
@@ -22,6 +22,7 @@ import org.hibernate.HibernateException;
 
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.lang.Nullable;
 import org.springframework.orm.jpa.EntityManagerFactoryUtils;
 
 /**
@@ -44,6 +45,7 @@ import org.springframework.orm.jpa.EntityManagerFactoryUtils;
 public class HibernateExceptionTranslator implements PersistenceExceptionTranslator {
 
 	@Override
+	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		if (ex instanceof HibernateException) {
 			return convertHibernateAccessException((HibernateException) ex);
diff --git a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTemplate.java b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTemplate.java
index 832d7cf5368..fb32d855984 100644
--- a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTemplate.java
+++ b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTemplate.java
@@ -328,6 +328,7 @@ public class HibernateTemplate implements HibernateOperations, InitializingBean
 
 
 	@Override
+	@Nullable
 	public <T> T execute(HibernateCallback<T> action) throws DataAccessException {
 		return doExecute(action, false);
 	}
@@ -453,11 +454,13 @@ public class HibernateTemplate implements HibernateOperations, InitializingBean
 	//-------------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public <T> T get(Class<T> entityClass, Serializable id) throws DataAccessException {
 		return get(entityClass, id, null);
 	}
 
 	@Override
+	@Nullable
 	public <T> T get(final Class<T> entityClass, final Serializable id, @Nullable final LockMode lockMode)
 			throws DataAccessException {
 
@@ -472,11 +475,13 @@ public class HibernateTemplate implements HibernateOperations, InitializingBean
 	}
 
 	@Override
+	@Nullable
 	public Object get(String entityName, Serializable id) throws DataAccessException {
 		return get(entityName, id, null);
 	}
 
 	@Override
+	@Nullable
 	public Object get(final String entityName, final Serializable id, @Nullable final LockMode lockMode)
 			throws DataAccessException {
 
diff --git a/spring-orm/src/main/java/org/springframework/orm/hibernate5/LocalSessionFactoryBean.java b/spring-orm/src/main/java/org/springframework/orm/hibernate5/LocalSessionFactoryBean.java
index a9b68a83018..2709aecbbd7 100644
--- a/spring-orm/src/main/java/org/springframework/orm/hibernate5/LocalSessionFactoryBean.java
+++ b/spring-orm/src/main/java/org/springframework/orm/hibernate5/LocalSessionFactoryBean.java
@@ -549,6 +549,7 @@ public class LocalSessionFactoryBean extends HibernateExceptionTranslator
 
 
 	@Override
+	@Nullable
 	public SessionFactory getObject() {
 		return this.sessionFactory;
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/AbstractEntityManagerFactoryBean.java b/spring-orm/src/main/java/org/springframework/orm/jpa/AbstractEntityManagerFactoryBean.java
index c9e7abf1185..c92f3a28429 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/AbstractEntityManagerFactoryBean.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/AbstractEntityManagerFactoryBean.java
@@ -495,6 +495,7 @@ public abstract class AbstractEntityManagerFactoryBean implements
 	 * @see EntityManagerFactoryUtils#convertJpaAccessExceptionIfPossible
 	 */
 	@Override
+	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		return (this.jpaDialect != null ? this.jpaDialect.translateExceptionIfPossible(ex) :
 				EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(ex));
@@ -522,11 +523,13 @@ public abstract class AbstractEntityManagerFactoryBean implements
 	}
 
 	@Override
+	@Nullable
 	public PersistenceUnitInfo getPersistenceUnitInfo() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public DataSource getDataSource() {
 		return null;
 	}
@@ -536,6 +539,7 @@ public abstract class AbstractEntityManagerFactoryBean implements
 	 * Return the singleton EntityManagerFactory.
 	 */
 	@Override
+	@Nullable
 	public EntityManagerFactory getObject() {
 		return this.entityManagerFactory;
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/DefaultJpaDialect.java b/spring-orm/src/main/java/org/springframework/orm/jpa/DefaultJpaDialect.java
index 3b228381f03..241aa924ffd 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/DefaultJpaDialect.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/DefaultJpaDialect.java
@@ -57,6 +57,7 @@ public class DefaultJpaDialect implements JpaDialect, Serializable {
 	 * @see #cleanupTransaction
 	 */
 	@Override
+	@Nullable
 	public Object beginTransaction(EntityManager entityManager, TransactionDefinition definition)
 			throws PersistenceException, SQLException, TransactionException {
 
@@ -70,6 +71,7 @@ public class DefaultJpaDialect implements JpaDialect, Serializable {
 	}
 
 	@Override
+	@Nullable
 	public Object prepareTransaction(EntityManager entityManager, boolean readOnly, @Nullable String name)
 			throws PersistenceException {
 
@@ -90,6 +92,7 @@ public class DefaultJpaDialect implements JpaDialect, Serializable {
 	 * indicating that no JDBC Connection can be provided.
 	 */
 	@Override
+	@Nullable
 	public ConnectionHandle getJdbcConnection(EntityManager entityManager, boolean readOnly)
 			throws PersistenceException, SQLException {
 
@@ -119,6 +122,7 @@ public class DefaultJpaDialect implements JpaDialect, Serializable {
 	 * @see EntityManagerFactoryUtils#convertJpaAccessExceptionIfPossible
 	 */
 	@Override
+	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		return EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(ex);
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/LocalContainerEntityManagerFactoryBean.java b/spring-orm/src/main/java/org/springframework/orm/jpa/LocalContainerEntityManagerFactoryBean.java
index ee96c8a2d86..9483e73eb9b 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/LocalContainerEntityManagerFactoryBean.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/LocalContainerEntityManagerFactoryBean.java
@@ -400,6 +400,7 @@ public class LocalContainerEntityManagerFactoryBean extends AbstractEntityManage
 	}
 
 	@Override
+	@Nullable
 	public String getPersistenceUnitName() {
 		if (this.persistenceUnitInfo != null) {
 			return this.persistenceUnitInfo.getPersistenceUnitName();
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/support/SharedEntityManagerBean.java b/spring-orm/src/main/java/org/springframework/orm/jpa/support/SharedEntityManagerBean.java
index df68fab2a53..b82af777c69 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/support/SharedEntityManagerBean.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/support/SharedEntityManagerBean.java
@@ -109,6 +109,7 @@ public class SharedEntityManagerBean extends EntityManagerFactoryAccessor
 
 
 	@Override
+	@Nullable
 	public EntityManager getObject() {
 		return this.shared;
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/AbstractJpaVendorAdapter.java b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/AbstractJpaVendorAdapter.java
index 20bb9a5f1cd..269d205cf54 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/AbstractJpaVendorAdapter.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/AbstractJpaVendorAdapter.java
@@ -118,16 +118,19 @@ public abstract class AbstractJpaVendorAdapter implements JpaVendorAdapter {
 
 
 	@Override
+	@Nullable
 	public String getPersistenceProviderRootPackage() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public Map<String, ?> getJpaPropertyMap() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public JpaDialect getJpaDialect() {
 		return null;
 	}
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/EclipseLinkJpaDialect.java b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/EclipseLinkJpaDialect.java
index f81b417bc72..0584c059023 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/EclipseLinkJpaDialect.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/EclipseLinkJpaDialect.java
@@ -72,6 +72,7 @@ public class EclipseLinkJpaDialect extends DefaultJpaDialect {
 
 
 	@Override
+	@Nullable
 	public Object beginTransaction(EntityManager entityManager, TransactionDefinition definition)
 			throws PersistenceException, SQLException, TransactionException {
 
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaDialect.java b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaDialect.java
index 1d573433f4a..84cc031dd5e 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaDialect.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaDialect.java
@@ -216,6 +216,7 @@ public class HibernateJpaDialect extends DefaultJpaDialect {
 	}
 
 	@Override
+	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		if (ex instanceof HibernateException) {
 			return convertHibernateAccessException((HibernateException) ex);
diff --git a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaSessionFactoryBean.java b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaSessionFactoryBean.java
index 163d69f890c..3942e7ba320 100644
--- a/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaSessionFactoryBean.java
+++ b/spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaSessionFactoryBean.java
@@ -22,6 +22,7 @@ import javax.persistence.EntityManagerFactory;
 import org.hibernate.SessionFactory;
 
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.lang.Nullable;
 import org.springframework.orm.jpa.EntityManagerFactoryAccessor;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
@@ -41,6 +42,7 @@ import org.springframework.util.ReflectionUtils;
 public class HibernateJpaSessionFactoryBean extends EntityManagerFactoryAccessor implements FactoryBean<SessionFactory> {
 
 	@Override
+	@Nullable
 	public SessionFactory getObject() {
 		EntityManagerFactory emf = getEntityManagerFactory();
 		Assert.state(emf != null, "EntityManagerFactory must not be null");
diff --git a/spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java b/spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java
index b0f01a791f4..50dbdfe0ea5 100644
--- a/spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java
+++ b/spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java
@@ -266,6 +266,7 @@ public class MockServletContext implements ServletContext {
 	}
 
 	@Override
+	@Nullable
 	public String getMimeType(String filePath) {
 		String extension = StringUtils.getFilenameExtension(filePath);
 		if (this.mimeTypes.containsKey(extension)) {
diff --git a/spring-test/src/main/java/org/springframework/test/context/cache/DefaultContextCache.java b/spring-test/src/main/java/org/springframework/test/context/cache/DefaultContextCache.java
index a9afcedb81f..61b8a48ce58 100644
--- a/spring-test/src/main/java/org/springframework/test/context/cache/DefaultContextCache.java
+++ b/spring-test/src/main/java/org/springframework/test/context/cache/DefaultContextCache.java
@@ -118,6 +118,7 @@ public class DefaultContextCache implements ContextCache {
 	 * {@inheritDoc}
 	 */
 	@Override
+	@Nullable
 	public ApplicationContext get(MergedContextConfiguration key) {
 		Assert.notNull(key, "Key must not be null");
 		ApplicationContext context = this.contextMap.get(key);
diff --git a/spring-test/src/main/java/org/springframework/test/context/support/DefaultTestContext.java b/spring-test/src/main/java/org/springframework/test/context/support/DefaultTestContext.java
index b383cd695bb..52c868cb108 100644
--- a/spring-test/src/main/java/org/springframework/test/context/support/DefaultTestContext.java
+++ b/spring-test/src/main/java/org/springframework/test/context/support/DefaultTestContext.java
@@ -147,6 +147,7 @@ public class DefaultTestContext implements TestContext {
 		return testMethod;
 	}
 
+	@Override
 	@Nullable
 	public final Throwable getTestException() {
 		return this.testException;
@@ -172,12 +173,14 @@ public class DefaultTestContext implements TestContext {
 	}
 
 	@Override
+	@Nullable
 	public Object getAttribute(String name) {
 		Assert.notNull(name, "Name must not be null");
 		return this.attributes.get(name);
 	}
 
 	@Override
+	@Nullable
 	public Object removeAttribute(String name) {
 		Assert.notNull(name, "Name must not be null");
 		return this.attributes.remove(name);
diff --git a/spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java b/spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java
index 0a62330774f..8847c7beb81 100644
--- a/spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java
+++ b/spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java
@@ -251,6 +251,7 @@ public abstract class TestContextTransactionUtils {
 		}
 
 		@Override
+		@Nullable
 		public String getName() {
 			return this.name;
 		}
diff --git a/spring-test/src/main/java/org/springframework/test/context/web/socket/MockServerContainerContextCustomizerFactory.java b/spring-test/src/main/java/org/springframework/test/context/web/socket/MockServerContainerContextCustomizerFactory.java
index c76959c35a4..4edd9fcb57b 100644
--- a/spring-test/src/main/java/org/springframework/test/context/web/socket/MockServerContainerContextCustomizerFactory.java
+++ b/spring-test/src/main/java/org/springframework/test/context/web/socket/MockServerContainerContextCustomizerFactory.java
@@ -20,6 +20,7 @@ import java.util.List;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.test.context.ContextConfigurationAttributes;
 import org.springframework.test.context.ContextCustomizer;
 import org.springframework.test.context.ContextCustomizerFactory;
@@ -46,6 +47,7 @@ class MockServerContainerContextCustomizerFactory implements ContextCustomizerFa
 
 
 	@Override
+	@Nullable
 	public ContextCustomizer createContextCustomizer(Class<?> testClass,
 			List<ContextConfigurationAttributes> configAttributes) {
 
diff --git a/spring-test/src/main/java/org/springframework/test/web/reactive/server/FluxExchangeResult.java b/spring-test/src/main/java/org/springframework/test/web/reactive/server/FluxExchangeResult.java
index 55e4af72aab..90e33d9aea0 100644
--- a/spring-test/src/main/java/org/springframework/test/web/reactive/server/FluxExchangeResult.java
+++ b/spring-test/src/main/java/org/springframework/test/web/reactive/server/FluxExchangeResult.java
@@ -21,6 +21,8 @@ import java.time.Duration;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.lang.Nullable;
+
 /**
  * {@code ExchangeResult} variant with the response body decoded as
  * {@code Flux<T>} but not yet consumed.
@@ -87,6 +89,7 @@ public class FluxExchangeResult<T> extends ExchangeResult {
 	 * via {@code getResponseBody.ignoreElements()}.
 	 */
 	@Override
+	@Nullable
 	public byte[] getResponseBodyContent() {
 		return this.body.ignoreElements()
 				.timeout(this.timeout, Mono.error(TIMEOUT_ERROR))
diff --git a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/MockMvcConfigurerAdapter.java b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/MockMvcConfigurerAdapter.java
index b5a67d1a869..95c6c216a64 100644
--- a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/MockMvcConfigurerAdapter.java
+++ b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/MockMvcConfigurerAdapter.java
@@ -16,6 +16,7 @@
 
 package org.springframework.test.web.servlet.setup;
 
+import org.springframework.lang.Nullable;
 import org.springframework.test.web.servlet.request.RequestPostProcessor;
 import org.springframework.web.context.WebApplicationContext;
 
@@ -32,6 +33,7 @@ public abstract class MockMvcConfigurerAdapter implements MockMvcConfigurer {
 	}
 
 	@Override
+	@Nullable
 	public RequestPostProcessor beforeMockMvcCreated(ConfigurableMockMvcBuilder<?> builder, WebApplicationContext cxt) {
 		return null;
 	}
diff --git a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StandaloneMockMvcBuilder.java b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StandaloneMockMvcBuilder.java
index b74fefee378..622af32aced 100644
--- a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StandaloneMockMvcBuilder.java
+++ b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StandaloneMockMvcBuilder.java
@@ -539,6 +539,7 @@ public class StandaloneMockMvcBuilder extends AbstractMockMvcBuilder<StandaloneM
 		}
 
 		@Override
+		@Nullable
 		public View resolveViewName(String viewName, Locale locale) throws Exception {
 			return this.view;
 		}
diff --git a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StubWebApplicationContext.java b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StubWebApplicationContext.java
index 5c9bc6897a1..cbca9b0cd6a 100644
--- a/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StubWebApplicationContext.java
+++ b/spring-test/src/main/java/org/springframework/test/web/servlet/setup/StubWebApplicationContext.java
@@ -275,6 +275,7 @@ class StubWebApplicationContext implements WebApplicationContext {
 	}
 
 	@Override
+	@Nullable
 	public <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType)
 			throws NoSuchBeanDefinitionException{
 
@@ -322,6 +323,7 @@ class StubWebApplicationContext implements WebApplicationContext {
 	//---------------------------------------------------------------------
 
 	@Override
+	@Nullable
 	public ClassLoader getClassLoader() {
 		return ClassUtils.getDefaultClassLoader();
 	}
@@ -399,11 +401,13 @@ class StubWebApplicationContext implements WebApplicationContext {
 		}
 
 		@Override
+		@Nullable
 		public Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName) {
 			throw new UnsupportedOperationException("Dependency resolution not supported");
 		}
 
 		@Override
+		@Nullable
 		public Object resolveDependency(DependencyDescriptor descriptor, @Nullable String requestingBeanName,
 				@Nullable Set<String> autowiredBeanNames, @Nullable TypeConverter typeConverter) {
 			throw new UnsupportedOperationException("Dependency resolution not supported");
diff --git a/spring-tx/src/main/java/org/springframework/dao/support/ChainedPersistenceExceptionTranslator.java b/spring-tx/src/main/java/org/springframework/dao/support/ChainedPersistenceExceptionTranslator.java
index 9c09bd00d99..32d53f2994a 100644
--- a/spring-tx/src/main/java/org/springframework/dao/support/ChainedPersistenceExceptionTranslator.java
+++ b/spring-tx/src/main/java/org/springframework/dao/support/ChainedPersistenceExceptionTranslator.java
@@ -20,6 +20,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.springframework.dao.DataAccessException;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -54,6 +55,7 @@ public class ChainedPersistenceExceptionTranslator implements PersistenceExcepti
 
 
 	@Override
+	@Nullable
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 		for (PersistenceExceptionTranslator pet : this.delegates) {
 			DataAccessException translatedDex = pet.translateExceptionIfPossible(ex);
diff --git a/spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java b/spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
index a17de4b3f3f..52a24dbe27e 100644
--- a/spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
+++ b/spring-tx/src/main/java/org/springframework/dao/support/DataAccessUtils.java
@@ -67,6 +67,7 @@ public abstract class DataAccessUtils {
 	 * @throws EmptyResultDataAccessException if no element at all
 	 * has been found in the given Collection
 	 */
+	@Nullable
 	public static <T> T requiredSingleResult(@Nullable Collection<T> results) throws IncorrectResultSizeDataAccessException {
 		int size = (results != null ? results.size() : 0);
 		if (size == 0) {
diff --git a/spring-tx/src/main/java/org/springframework/jca/cci/core/CciTemplate.java b/spring-tx/src/main/java/org/springframework/jca/cci/core/CciTemplate.java
index 0c3a0af8bba..7d9343caa25 100644
--- a/spring-tx/src/main/java/org/springframework/jca/cci/core/CciTemplate.java
+++ b/spring-tx/src/main/java/org/springframework/jca/cci/core/CciTemplate.java
@@ -204,6 +204,7 @@ public class CciTemplate implements CciOperations {
 
 
 	@Override
+	@Nullable
 	public <T> T execute(ConnectionCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 		ConnectionFactory connectionFactory = obtainConnectionFactory();
@@ -226,6 +227,7 @@ public class CciTemplate implements CciOperations {
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(final InteractionCallback<T> action) throws DataAccessException {
 		Assert.notNull(action, "Callback object must not be null");
 		return execute((ConnectionCallback<T>) (connection, connectionFactory) -> {
@@ -240,6 +242,7 @@ public class CciTemplate implements CciOperations {
 	}
 
 	@Override
+	@Nullable
 	public Record execute(InteractionSpec spec, Record inputRecord) throws DataAccessException {
 		return doExecute(spec, inputRecord, null, new SimpleRecordExtractor());
 	}
diff --git a/spring-tx/src/main/java/org/springframework/jca/support/LocalConnectionFactoryBean.java b/spring-tx/src/main/java/org/springframework/jca/support/LocalConnectionFactoryBean.java
index 70c1b13c3f9..88badca7f7c 100644
--- a/spring-tx/src/main/java/org/springframework/jca/support/LocalConnectionFactoryBean.java
+++ b/spring-tx/src/main/java/org/springframework/jca/support/LocalConnectionFactoryBean.java
@@ -128,6 +128,7 @@ public class LocalConnectionFactoryBean implements FactoryBean<Object>, Initiali
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.connectionFactory;
 	}
diff --git a/spring-tx/src/main/java/org/springframework/jca/support/ResourceAdapterFactoryBean.java b/spring-tx/src/main/java/org/springframework/jca/support/ResourceAdapterFactoryBean.java
index 23f511f3fee..319224c8b60 100644
--- a/spring-tx/src/main/java/org/springframework/jca/support/ResourceAdapterFactoryBean.java
+++ b/spring-tx/src/main/java/org/springframework/jca/support/ResourceAdapterFactoryBean.java
@@ -129,6 +129,7 @@ public class ResourceAdapterFactoryBean implements FactoryBean<ResourceAdapter>,
 
 
 	@Override
+	@Nullable
 	public ResourceAdapter getObject() {
 		return this.resourceAdapter;
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/annotation/AnnotationTransactionAttributeSource.java b/spring-tx/src/main/java/org/springframework/transaction/annotation/AnnotationTransactionAttributeSource.java
index 53c23a14a4b..3eddcea8c23 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/annotation/AnnotationTransactionAttributeSource.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/annotation/AnnotationTransactionAttributeSource.java
@@ -130,11 +130,13 @@ public class AnnotationTransactionAttributeSource extends AbstractFallbackTransa
 
 
 	@Override
+	@Nullable
 	protected TransactionAttribute findTransactionAttribute(Method method) {
 		return determineTransactionAttribute(method);
 	}
 
 	@Override
+	@Nullable
 	protected TransactionAttribute findTransactionAttribute(Class<?> clazz) {
 		return determineTransactionAttribute(clazz);
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/annotation/Ejb3TransactionAnnotationParser.java b/spring-tx/src/main/java/org/springframework/transaction/annotation/Ejb3TransactionAnnotationParser.java
index c7e20cf1dc4..7e989876f85 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/annotation/Ejb3TransactionAnnotationParser.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/annotation/Ejb3TransactionAnnotationParser.java
@@ -21,6 +21,7 @@ import java.lang.reflect.AnnotatedElement;
 import javax.ejb.ApplicationException;
 import javax.ejb.TransactionAttributeType;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.interceptor.DefaultTransactionAttribute;
 import org.springframework.transaction.interceptor.TransactionAttribute;
 
@@ -35,6 +36,7 @@ import org.springframework.transaction.interceptor.TransactionAttribute;
 public class Ejb3TransactionAnnotationParser implements TransactionAnnotationParser, Serializable {
 
 	@Override
+	@Nullable
 	public TransactionAttribute parseTransactionAnnotation(AnnotatedElement ae) {
 		javax.ejb.TransactionAttribute ann = ae.getAnnotation(javax.ejb.TransactionAttribute.class);
 		if (ann != null) {
diff --git a/spring-tx/src/main/java/org/springframework/transaction/annotation/JtaTransactionAnnotationParser.java b/spring-tx/src/main/java/org/springframework/transaction/annotation/JtaTransactionAnnotationParser.java
index 9cb041b272c..0d4901b918a 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/annotation/JtaTransactionAnnotationParser.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/annotation/JtaTransactionAnnotationParser.java
@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.interceptor.NoRollbackRuleAttribute;
 import org.springframework.transaction.interceptor.RollbackRuleAttribute;
 import org.springframework.transaction.interceptor.RuleBasedTransactionAttribute;
@@ -38,6 +39,7 @@ import org.springframework.transaction.interceptor.TransactionAttribute;
 public class JtaTransactionAnnotationParser implements TransactionAnnotationParser, Serializable {
 
 	@Override
+	@Nullable
 	public TransactionAttribute parseTransactionAnnotation(AnnotatedElement ae) {
 		AnnotationAttributes attributes =
 				AnnotatedElementUtils.getMergedAnnotationAttributes(ae, javax.transaction.Transactional.class);
diff --git a/spring-tx/src/main/java/org/springframework/transaction/annotation/SpringTransactionAnnotationParser.java b/spring-tx/src/main/java/org/springframework/transaction/annotation/SpringTransactionAnnotationParser.java
index f356afac1e0..92a95709994 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/annotation/SpringTransactionAnnotationParser.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/annotation/SpringTransactionAnnotationParser.java
@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.interceptor.NoRollbackRuleAttribute;
 import org.springframework.transaction.interceptor.RollbackRuleAttribute;
 import org.springframework.transaction.interceptor.RuleBasedTransactionAttribute;
@@ -38,6 +39,7 @@ import org.springframework.transaction.interceptor.TransactionAttribute;
 public class SpringTransactionAnnotationParser implements TransactionAnnotationParser, Serializable {
 
 	@Override
+	@Nullable
 	public TransactionAttribute parseTransactionAnnotation(AnnotatedElement ae) {
 		AnnotationAttributes attributes = AnnotatedElementUtils.findMergedAnnotationAttributes(
 				ae, Transactional.class, false, false);
diff --git a/spring-tx/src/main/java/org/springframework/transaction/config/AnnotationDrivenBeanDefinitionParser.java b/spring-tx/src/main/java/org/springframework/transaction/config/AnnotationDrivenBeanDefinitionParser.java
index ce3300aafac..eb827bf6549 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/config/AnnotationDrivenBeanDefinitionParser.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/config/AnnotationDrivenBeanDefinitionParser.java
@@ -26,6 +26,7 @@ import org.springframework.beans.factory.parsing.CompositeComponentDefinition;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.event.TransactionalEventListenerFactory;
 import org.springframework.transaction.interceptor.BeanFactoryTransactionAttributeSourceAdvisor;
 import org.springframework.transaction.interceptor.TransactionInterceptor;
@@ -56,6 +57,7 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 	 * with the container as necessary.
 	 */
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		registerTransactionalEventListenerFactory(parserContext);
 		String mode = element.getAttribute("mode");
diff --git a/spring-tx/src/main/java/org/springframework/transaction/config/JtaTransactionManagerFactoryBean.java b/spring-tx/src/main/java/org/springframework/transaction/config/JtaTransactionManagerFactoryBean.java
index 4fe53cd7820..3d1fbb3638f 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/config/JtaTransactionManagerFactoryBean.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/config/JtaTransactionManagerFactoryBean.java
@@ -70,6 +70,7 @@ public class JtaTransactionManagerFactoryBean implements FactoryBean<JtaTransact
 
 
 	@Override
+	@Nullable
 	public JtaTransactionManager getObject() {
 		return this.transactionManager;
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/AbstractFallbackTransactionAttributeSource.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/AbstractFallbackTransactionAttributeSource.java
index 955c7816859..364b4472d2e 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/AbstractFallbackTransactionAttributeSource.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/AbstractFallbackTransactionAttributeSource.java
@@ -82,6 +82,7 @@ public abstract class AbstractFallbackTransactionAttributeSource implements Tran
 	 * is not transactional
 	 */
 	@Override
+	@Nullable
 	public TransactionAttribute getTransactionAttribute(Method method, @Nullable Class<?> targetClass) {
 		if (method.getDeclaringClass() == Object.class) {
 			return null;
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/BeanFactoryTransactionAttributeSourceAdvisor.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/BeanFactoryTransactionAttributeSourceAdvisor.java
index ba034b064f1..50df3aeb38e 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/BeanFactoryTransactionAttributeSourceAdvisor.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/BeanFactoryTransactionAttributeSourceAdvisor.java
@@ -39,6 +39,7 @@ public class BeanFactoryTransactionAttributeSourceAdvisor extends AbstractBeanFa
 
 	private final TransactionAttributeSourcePointcut pointcut = new TransactionAttributeSourcePointcut() {
 		@Override
+		@Nullable
 		protected TransactionAttributeSource getTransactionAttributeSource() {
 			return transactionAttributeSource;
 		}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/DelegatingTransactionAttribute.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/DelegatingTransactionAttribute.java
index 84db321374c..26422009e41 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/DelegatingTransactionAttribute.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/DelegatingTransactionAttribute.java
@@ -18,6 +18,7 @@ package org.springframework.transaction.interceptor;
 
 import java.io.Serializable;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.support.DelegatingTransactionDefinition;
 
 /**
@@ -47,6 +48,7 @@ public abstract class DelegatingTransactionAttribute extends DelegatingTransacti
 
 
 	@Override
+	@Nullable
 	public String getQualifier() {
 		return this.targetAttribute.getQualifier();
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/MatchAlwaysTransactionAttributeSource.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/MatchAlwaysTransactionAttributeSource.java
index 15941dedf22..b9b4a7ef12c 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/MatchAlwaysTransactionAttributeSource.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/MatchAlwaysTransactionAttributeSource.java
@@ -53,6 +53,7 @@ public class MatchAlwaysTransactionAttributeSource implements TransactionAttribu
 
 
 	@Override
+	@Nullable
 	public TransactionAttribute getTransactionAttribute(Method method, @Nullable Class<?> targetClass) {
 		return (ClassUtils.isUserLevelMethod(method) ? this.transactionAttribute : null);
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/MethodMapTransactionAttributeSource.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/MethodMapTransactionAttributeSource.java
index 252dab3984f..66dfb28398d 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/MethodMapTransactionAttributeSource.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/MethodMapTransactionAttributeSource.java
@@ -207,6 +207,7 @@ public class MethodMapTransactionAttributeSource
 
 
 	@Override
+	@Nullable
 	public TransactionAttribute getTransactionAttribute(Method method, @Nullable Class<?> targetClass) {
 		if (this.eagerlyInitialized) {
 			return this.transactionAttributeMap.get(method);
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/NameMatchTransactionAttributeSource.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/NameMatchTransactionAttributeSource.java
index 9edc18d400a..43a239ab484 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/NameMatchTransactionAttributeSource.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/NameMatchTransactionAttributeSource.java
@@ -99,6 +99,7 @@ public class NameMatchTransactionAttributeSource implements TransactionAttribute
 
 
 	@Override
+	@Nullable
 	public TransactionAttribute getTransactionAttribute(Method method, @Nullable Class<?> targetClass) {
 		if (!ClassUtils.isUserLevelMethod(method)) {
 			return null;
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java
index 07e17055bd8..1b6726d160a 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java
@@ -448,6 +448,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 		if (txAttr != null && txAttr.getName() == null) {
 			txAttr = new DelegatingTransactionAttribute(txAttr) {
 				@Override
+				@Nullable
 				public String getName() {
 					return joinpointIdentification;
 				}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttributeSourceAdvisor.java b/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttributeSourceAdvisor.java
index bf91b50c17b..2d5489c3c7e 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttributeSourceAdvisor.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttributeSourceAdvisor.java
@@ -45,6 +45,7 @@ public class TransactionAttributeSourceAdvisor extends AbstractPointcutAdvisor {
 
 	private final TransactionAttributeSourcePointcut pointcut = new TransactionAttributeSourcePointcut() {
 		@Override
+		@Nullable
 		protected TransactionAttributeSource getTransactionAttributeSource() {
 			return (transactionInterceptor != null ? transactionInterceptor.getTransactionAttributeSource() : null);
 		}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/jta/WebLogicJtaTransactionManager.java b/spring-tx/src/main/java/org/springframework/transaction/jta/WebLogicJtaTransactionManager.java
index ef9ad33c4af..4d8eaaf307c 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/jta/WebLogicJtaTransactionManager.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/jta/WebLogicJtaTransactionManager.java
@@ -113,6 +113,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 	}
 
 	@Override
+	@Nullable
 	protected UserTransaction retrieveUserTransaction() throws TransactionSystemException {
 		Object helper = loadWebLogicTransactionHelper();
 		try {
@@ -131,6 +132,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 	}
 
 	@Override
+	@Nullable
 	protected TransactionManager retrieveTransactionManager() throws TransactionSystemException {
 		Object helper = loadWebLogicTransactionHelper();
 		try {
diff --git a/spring-tx/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java b/spring-tx/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
index 9e334ae79b7..039d15297e7 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java
@@ -229,6 +229,7 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 
 
 	@Override
+	@Nullable
 	public <T> T execute(@Nullable TransactionDefinition definition, TransactionCallback<T> callback)
 			throws TransactionException {
 
diff --git a/spring-tx/src/main/java/org/springframework/transaction/support/DelegatingTransactionDefinition.java b/spring-tx/src/main/java/org/springframework/transaction/support/DelegatingTransactionDefinition.java
index e05c4e27844..481c9e6a487 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/support/DelegatingTransactionDefinition.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/support/DelegatingTransactionDefinition.java
@@ -18,6 +18,7 @@ package org.springframework.transaction.support;
 
 import java.io.Serializable;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.util.Assert;
 
@@ -67,6 +68,7 @@ public abstract class DelegatingTransactionDefinition implements TransactionDefi
 	}
 
 	@Override
+	@Nullable
 	public String getName() {
 		return this.targetDefinition.getName();
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/support/SimpleTransactionScope.java b/spring-tx/src/main/java/org/springframework/transaction/support/SimpleTransactionScope.java
index c2b62cefd56..e51030a52b4 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/support/SimpleTransactionScope.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/support/SimpleTransactionScope.java
@@ -22,6 +22,7 @@ import java.util.Map;
 
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.config.Scope;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -60,6 +61,7 @@ public class SimpleTransactionScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		ScopedObjectsHolder scopedObjects = (ScopedObjectsHolder) TransactionSynchronizationManager.getResource(this);
 		if (scopedObjects != null) {
@@ -80,11 +82,13 @@ public class SimpleTransactionScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveContextualObject(String key) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public String getConversationId() {
 		return TransactionSynchronizationManager.getCurrentTransactionName();
 	}
diff --git a/spring-tx/src/main/java/org/springframework/transaction/support/TransactionCallbackWithoutResult.java b/spring-tx/src/main/java/org/springframework/transaction/support/TransactionCallbackWithoutResult.java
index 8088bc2870b..facf83cc6a6 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/support/TransactionCallbackWithoutResult.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/support/TransactionCallbackWithoutResult.java
@@ -16,6 +16,7 @@
 
 package org.springframework.transaction.support;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionStatus;
 
 /**
@@ -30,6 +31,7 @@ import org.springframework.transaction.TransactionStatus;
 public abstract class TransactionCallbackWithoutResult implements TransactionCallback<Object> {
 
 	@Override
+	@Nullable
 	public final Object doInTransaction(TransactionStatus status) {
 		doInTransactionWithoutResult(status);
 		return null;
diff --git a/spring-tx/src/main/java/org/springframework/transaction/support/TransactionTemplate.java b/spring-tx/src/main/java/org/springframework/transaction/support/TransactionTemplate.java
index 05da1745350..f4465f7f55a 100644
--- a/spring-tx/src/main/java/org/springframework/transaction/support/TransactionTemplate.java
+++ b/spring-tx/src/main/java/org/springframework/transaction/support/TransactionTemplate.java
@@ -126,6 +126,7 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 
 
 	@Override
+	@Nullable
 	public <T> T execute(TransactionCallback<T> action) throws TransactionException {
 		Assert.state(this.transactionManager != null, "No PlatformTransactionManager set");
 
diff --git a/spring-web/src/main/java/org/springframework/http/HttpHeaders.java b/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
index 8349df24a11..5ef7be1f677 100644
--- a/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
+++ b/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
@@ -1391,6 +1391,7 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	 * @return the first header value, or {@code null} if none
 	 */
 	@Override
+	@Nullable
 	public String getFirst(String headerName) {
 		List<String> headerValues = this.headers.get(headerName);
 		return (headerValues != null ? headerValues.get(0) : null);
diff --git a/spring-web/src/main/java/org/springframework/http/client/BufferingClientHttpRequestWrapper.java b/spring-web/src/main/java/org/springframework/http/client/BufferingClientHttpRequestWrapper.java
index 62a85c058db..2926031364b 100644
--- a/spring-web/src/main/java/org/springframework/http/client/BufferingClientHttpRequestWrapper.java
+++ b/spring-web/src/main/java/org/springframework/http/client/BufferingClientHttpRequestWrapper.java
@@ -21,6 +21,7 @@ import java.net.URI;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StreamUtils;
 
 /**
@@ -40,6 +41,7 @@ final class BufferingClientHttpRequestWrapper extends AbstractBufferingClientHtt
 
 
 	@Override
+	@Nullable
 	public HttpMethod getMethod() {
 		return this.request.getMethod();
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/client/support/HttpRequestWrapper.java b/spring-web/src/main/java/org/springframework/http/client/support/HttpRequestWrapper.java
index e46e7456e16..e8f6fd4367e 100644
--- a/spring-web/src/main/java/org/springframework/http/client/support/HttpRequestWrapper.java
+++ b/spring-web/src/main/java/org/springframework/http/client/support/HttpRequestWrapper.java
@@ -21,6 +21,7 @@ import java.net.URI;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpRequest;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -58,6 +59,7 @@ public class HttpRequestWrapper implements HttpRequest {
 	 * Return the method of the wrapped request.
 	 */
 	@Override
+	@Nullable
 	public HttpMethod getMethod() {
 		return this.request.getMethod();
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/client/support/ProxyFactoryBean.java b/spring-web/src/main/java/org/springframework/http/client/support/ProxyFactoryBean.java
index 2029ab409dd..94c40f4a82b 100644
--- a/spring-web/src/main/java/org/springframework/http/client/support/ProxyFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/http/client/support/ProxyFactoryBean.java
@@ -83,6 +83,7 @@ public class ProxyFactoryBean implements FactoryBean<Proxy>, InitializingBean {
 
 
 	@Override
+	@Nullable
 	public Proxy getObject() {
 		return this.proxy;
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
index 8890e10496b..332030472ce 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
@@ -90,6 +90,7 @@ public class ResourceHttpMessageConverter extends AbstractHttpMessageConverter<R
 			byte[] body = StreamUtils.copyToByteArray(inputMessage.getBody());
 			return new ByteArrayResource(body) {
 				@Override
+				@Nullable
 				public String getFilename() {
 					return inputMessage.getHeaders().getContentDisposition().getFilename();
 				}
diff --git a/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
index 70ebf5a6272..7d79fe2a3d9 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
@@ -343,6 +343,7 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 	}
 
 	@Override
+	@Nullable
 	protected MediaType getDefaultContentType(Object object) throws IOException {
 		if (object instanceof MappingJacksonValue) {
 			object = ((MappingJacksonValue) object).getValue();
diff --git a/spring-web/src/main/java/org/springframework/http/converter/json/GsonFactoryBean.java b/spring-web/src/main/java/org/springframework/http/converter/json/GsonFactoryBean.java
index 4ed089ec8b7..9108f655020 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/json/GsonFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/json/GsonFactoryBean.java
@@ -132,6 +132,7 @@ public class GsonFactoryBean implements FactoryBean<Gson>, InitializingBean {
 	 * Return the created Gson instance.
 	 */
 	@Override
+	@Nullable
 	public Gson getObject() {
 		return this.gson;
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.java b/spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.java
index f52578515bb..7396b933afe 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperFactoryBean.java
@@ -466,6 +466,7 @@ public class Jackson2ObjectMapperFactoryBean implements FactoryBean<ObjectMapper
 	 * Return the singleton ObjectMapper.
 	 */
 	@Override
+	@Nullable
 	public ObjectMapper getObject() {
 		return this.objectMapper;
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/server/ServletServerHttpResponse.java b/spring-web/src/main/java/org/springframework/http/server/ServletServerHttpResponse.java
index af3e3b282e6..2fd1b5734a8 100644
--- a/spring-web/src/main/java/org/springframework/http/server/ServletServerHttpResponse.java
+++ b/spring-web/src/main/java/org/springframework/http/server/ServletServerHttpResponse.java
@@ -26,6 +26,7 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 
@@ -138,6 +139,7 @@ public class ServletServerHttpResponse implements ServerHttpResponse {
 		}
 
 		@Override
+		@Nullable
 		public String getFirst(String headerName) {
 			String value = servletResponse.getHeader(headerName);
 			if (value != null) {
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilder.java b/spring-web/src/main/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilder.java
index 34ef54ac5f1..fa39fb1e410 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilder.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilder.java
@@ -162,6 +162,7 @@ class DefaultServerHttpRequestBuilder implements ServerHttpRequest.Builder {
 		}
 
 		@Override
+		@Nullable
 		public HttpMethod getMethod() {
 			return (this.httpMethod != null ? this.httpMethod : super.getMethod());
 		}
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpRequestDecorator.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpRequestDecorator.java
index 423e60e0fa9..116aac326b8 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpRequestDecorator.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ServerHttpRequestDecorator.java
@@ -26,6 +26,7 @@ import org.springframework.http.HttpCookie;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.server.RequestPath;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.MultiValueMap;
 
@@ -55,6 +56,7 @@ public class ServerHttpRequestDecorator implements ServerHttpRequest {
 	// ServerHttpRequest delegation methods...
 
 	@Override
+	@Nullable
 	public HttpMethod getMethod() {
 		return getDelegate().getMethod();
 	}
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java
index 3fe9b83aa57..3a984ed9ab0 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java
@@ -246,6 +246,7 @@ public class ServletServerHttpRequest extends AbstractServerHttpRequest {
 		}
 
 		@Override
+		@Nullable
 		protected DataBuffer read() throws IOException {
 			if (this.inputStream.isReady()) {
 				return readFromInputStream();
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowServerHttpRequest.java b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowServerHttpRequest.java
index 502d8089a66..1fd119d6de1 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowServerHttpRequest.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowServerHttpRequest.java
@@ -143,6 +143,7 @@ public class UndertowServerHttpRequest extends AbstractServerHttpRequest {
 		}
 
 		@Override
+		@Nullable
 		protected DataBuffer read() throws IOException {
 			if (this.pooledByteBuffer == null) {
 				this.pooledByteBuffer = this.byteBufferPool.allocate();
diff --git a/spring-web/src/main/java/org/springframework/remoting/caucho/HessianClientInterceptor.java b/spring-web/src/main/java/org/springframework/remoting/caucho/HessianClientInterceptor.java
index fd95a9a618a..ecf4f43b3ad 100644
--- a/spring-web/src/main/java/org/springframework/remoting/caucho/HessianClientInterceptor.java
+++ b/spring-web/src/main/java/org/springframework/remoting/caucho/HessianClientInterceptor.java
@@ -239,6 +239,7 @@ public class HessianClientInterceptor extends UrlBasedRemoteAccessor implements
 
 
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation invocation) throws Throwable {
 		if (this.hessianProxy == null) {
 			throw new IllegalStateException("HessianClientInterceptor is not properly initialized - " +
diff --git a/spring-web/src/main/java/org/springframework/remoting/caucho/HessianProxyFactoryBean.java b/spring-web/src/main/java/org/springframework/remoting/caucho/HessianProxyFactoryBean.java
index d3dbe282331..aa1c33e7485 100644
--- a/spring-web/src/main/java/org/springframework/remoting/caucho/HessianProxyFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/remoting/caucho/HessianProxyFactoryBean.java
@@ -55,6 +55,7 @@ public class HessianProxyFactoryBean extends HessianClientInterceptor implements
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.serviceProxy;
 	}
diff --git a/spring-web/src/main/java/org/springframework/remoting/httpinvoker/HttpInvokerProxyFactoryBean.java b/spring-web/src/main/java/org/springframework/remoting/httpinvoker/HttpInvokerProxyFactoryBean.java
index 224a4a81590..cefcd0e8b28 100644
--- a/spring-web/src/main/java/org/springframework/remoting/httpinvoker/HttpInvokerProxyFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/remoting/httpinvoker/HttpInvokerProxyFactoryBean.java
@@ -70,6 +70,7 @@ public class HttpInvokerProxyFactoryBean extends HttpInvokerClientInterceptor im
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.serviceProxy;
 	}
diff --git a/spring-web/src/main/java/org/springframework/remoting/jaxws/JaxWsPortProxyFactoryBean.java b/spring-web/src/main/java/org/springframework/remoting/jaxws/JaxWsPortProxyFactoryBean.java
index 97ec0fa2ee1..d5a7fc65f79 100644
--- a/spring-web/src/main/java/org/springframework/remoting/jaxws/JaxWsPortProxyFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/remoting/jaxws/JaxWsPortProxyFactoryBean.java
@@ -56,6 +56,7 @@ public class JaxWsPortProxyFactoryBean extends JaxWsPortClientInterceptor implem
 
 
 	@Override
+	@Nullable
 	public Object getObject() {
 		return this.serviceProxy;
 	}
diff --git a/spring-web/src/main/java/org/springframework/remoting/jaxws/LocalJaxWsServiceFactoryBean.java b/spring-web/src/main/java/org/springframework/remoting/jaxws/LocalJaxWsServiceFactoryBean.java
index 315ff679211..ae9efaa3af5 100644
--- a/spring-web/src/main/java/org/springframework/remoting/jaxws/LocalJaxWsServiceFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/remoting/jaxws/LocalJaxWsServiceFactoryBean.java
@@ -49,6 +49,7 @@ public class LocalJaxWsServiceFactoryBean extends LocalJaxWsServiceFactory
 	}
 
 	@Override
+	@Nullable
 	public Service getObject() {
 		return this.service;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java b/spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java
index 5fa34b9386b..1ff43dab43e 100644
--- a/spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java
@@ -344,6 +344,7 @@ public class ContentNegotiationManagerFactoryBean
 
 
 	@Override
+	@Nullable
 	public ContentNegotiationManager getObject() {
 		return this.contentNegotiationManager;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/accept/ParameterContentNegotiationStrategy.java b/spring-web/src/main/java/org/springframework/web/accept/ParameterContentNegotiationStrategy.java
index 5f4c8c2acdf..f2d3a258787 100644
--- a/spring-web/src/main/java/org/springframework/web/accept/ParameterContentNegotiationStrategy.java
+++ b/spring-web/src/main/java/org/springframework/web/accept/ParameterContentNegotiationStrategy.java
@@ -19,6 +19,7 @@ package org.springframework.web.accept;
 import java.util.Map;
 
 import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.context.request.NativeWebRequest;
 
@@ -62,6 +63,7 @@ public class ParameterContentNegotiationStrategy extends AbstractMappingContentN
 
 
 	@Override
+	@Nullable
 	protected String getMediaTypeKey(NativeWebRequest request) {
 		return request.getParameter(getParameterName());
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java b/spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java
index 2c627898566..d9ebb00804c 100644
--- a/spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java
+++ b/spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java
@@ -83,6 +83,7 @@ public class PathExtensionContentNegotiationStrategy extends AbstractMappingCont
 	}
 
 	@Override
+	@Nullable
 	protected String getMediaTypeKey(NativeWebRequest webRequest) {
 		HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
 		if (request == null) {
diff --git a/spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java b/spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java
index e3930d450bc..9ccf4dbea25 100644
--- a/spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java
+++ b/spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java
@@ -67,6 +67,7 @@ public class ServletPathExtensionContentNegotiationStrategy extends PathExtensio
 	 * {@link org.springframework.http.MediaTypeFactory} lookup.
 	 */
 	@Override
+	@Nullable
 	protected MediaType handleNoMatch(NativeWebRequest webRequest, String extension)
 			throws HttpMediaTypeNotAcceptableException {
 
diff --git a/spring-web/src/main/java/org/springframework/web/bind/EscapedErrors.java b/spring-web/src/main/java/org/springframework/web/bind/EscapedErrors.java
index 2728be6ade0..26adc1974b1 100644
--- a/spring-web/src/main/java/org/springframework/web/bind/EscapedErrors.java
+++ b/spring-web/src/main/java/org/springframework/web/bind/EscapedErrors.java
@@ -151,6 +151,7 @@ public class EscapedErrors implements Errors {
 	}
 
 	@Override
+	@Nullable
 	public ObjectError getGlobalError() {
 		return escapeObjectError(this.source.getGlobalError());
 	}
@@ -171,6 +172,7 @@ public class EscapedErrors implements Errors {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError() {
 		return this.source.getFieldError();
 	}
@@ -191,17 +193,20 @@ public class EscapedErrors implements Errors {
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError(String field) {
 		return escapeObjectError(this.source.getFieldError(field));
 	}
 
 	@Override
+	@Nullable
 	public Object getFieldValue(String field) {
 		Object value = this.source.getFieldValue(field);
 		return (value instanceof String ? HtmlUtils.htmlEscape((String) value) : value);
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getFieldType(String field) {
 		return this.source.getFieldType(field);
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/bind/support/DefaultSessionAttributeStore.java b/spring-web/src/main/java/org/springframework/web/bind/support/DefaultSessionAttributeStore.java
index 1102bdbf1d2..849c2be6dc4 100644
--- a/spring-web/src/main/java/org/springframework/web/bind/support/DefaultSessionAttributeStore.java
+++ b/spring-web/src/main/java/org/springframework/web/bind/support/DefaultSessionAttributeStore.java
@@ -57,6 +57,7 @@ public class DefaultSessionAttributeStore implements SessionAttributeStore {
 	}
 
 	@Override
+	@Nullable
 	public Object retrieveAttribute(WebRequest request, String attributeName) {
 		Assert.notNull(request, "WebRequest must not be null");
 		Assert.notNull(attributeName, "Attribute name must not be null");
diff --git a/spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeBindException.java b/spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeBindException.java
index badc737d51c..a14e06d51ae 100644
--- a/spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeBindException.java
+++ b/spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeBindException.java
@@ -157,6 +157,7 @@ public class WebExchangeBindException extends ServerWebInputException implements
 	}
 
 	@Override
+	@Nullable
 	public ObjectError getGlobalError() {
 		return this.bindingResult.getGlobalError();
 	}
@@ -177,6 +178,7 @@ public class WebExchangeBindException extends ServerWebInputException implements
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError() {
 		return this.bindingResult.getFieldError();
 	}
@@ -197,16 +199,19 @@ public class WebExchangeBindException extends ServerWebInputException implements
 	}
 
 	@Override
+	@Nullable
 	public FieldError getFieldError(String field) {
 		return this.bindingResult.getFieldError(field);
 	}
 
 	@Override
+	@Nullable
 	public Object getFieldValue(String field) {
 		return this.bindingResult.getFieldValue(field);
 	}
 
 	@Override
+	@Nullable
 	public Class<?> getFieldType(String field) {
 		return this.bindingResult.getFieldType(field);
 	}
@@ -222,17 +227,20 @@ public class WebExchangeBindException extends ServerWebInputException implements
 	}
 
 	@Override
+	@Nullable
 	public Object getRawFieldValue(String field) {
 		return this.bindingResult.getRawFieldValue(field);
 	}
 
 	@Override
 	@SuppressWarnings("rawtypes")
+	@Nullable
 	public PropertyEditor findEditor(@Nullable String field, @Nullable Class valueType) {
 		return this.bindingResult.findEditor(field, valueType);
 	}
 
 	@Override
+	@Nullable
 	public PropertyEditorRegistry getPropertyEditorRegistry() {
 		return this.bindingResult.getPropertyEditorRegistry();
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/client/AsyncRestTemplate.java b/spring-web/src/main/java/org/springframework/web/client/AsyncRestTemplate.java
index d03be0125d3..79188ce8e24 100644
--- a/spring-web/src/main/java/org/springframework/web/client/AsyncRestTemplate.java
+++ b/spring-web/src/main/java/org/springframework/web/client/AsyncRestTemplate.java
@@ -297,6 +297,7 @@ public class AsyncRestTemplate extends org.springframework.http.client.support.I
 	private static ListenableFuture<URI> adaptToLocationHeader(ListenableFuture<HttpHeaders> future) {
 		return new ListenableFutureAdapter<URI, HttpHeaders>(future) {
 			@Override
+			@Nullable
 			protected URI adapt(HttpHeaders headers) throws ExecutionException {
 				return headers.getLocation();
 			}
@@ -607,6 +608,7 @@ public class AsyncRestTemplate extends org.springframework.http.client.support.I
 		}
 
 		@Override
+		@Nullable
 		protected final T adapt(ClientHttpResponse response) throws ExecutionException {
 			try {
 				if (!getErrorHandler().hasError(response)) {
@@ -660,6 +662,7 @@ public class AsyncRestTemplate extends org.springframework.http.client.support.I
 					return request.getBody();
 				}
 				@Override
+				@Nullable
 				public HttpMethod getMethod() {
 					return request.getMethod();
 				}
diff --git a/spring-web/src/main/java/org/springframework/web/client/RestTemplate.java b/spring-web/src/main/java/org/springframework/web/client/RestTemplate.java
index d1c8de28a1a..eed40af3575 100644
--- a/spring-web/src/main/java/org/springframework/web/client/RestTemplate.java
+++ b/spring-web/src/main/java/org/springframework/web/client/RestTemplate.java
@@ -311,6 +311,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	// GET
 
 	@Override
+	@Nullable
 	public <T> T getForObject(String url, Class<T> responseType, Object... uriVariables) throws RestClientException {
 		RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
@@ -319,6 +320,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> uriVariables) throws RestClientException {
 		RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
@@ -327,6 +329,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException {
 		RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
@@ -381,6 +384,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	// POST
 
 	@Override
+	@Nullable
 	public URI postForLocation(String url, @Nullable Object request, Object... uriVariables) throws RestClientException {
 		RequestCallback requestCallback = httpEntityCallback(request);
 		HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);
@@ -388,6 +392,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public URI postForLocation(String url, @Nullable Object request, Map<String, ?> uriVariables) throws RestClientException {
 		RequestCallback requestCallback = httpEntityCallback(request);
 		HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);
@@ -395,6 +400,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public URI postForLocation(URI url, @Nullable Object request) throws RestClientException {
 		RequestCallback requestCallback = httpEntityCallback(request);
 		HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor());
@@ -402,6 +408,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T postForObject(String url, @Nullable Object request, Class<T> responseType, Object... uriVariables)
 			throws RestClientException {
 
@@ -412,6 +419,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T postForObject(String url, @Nullable Object request, Class<T> responseType, Map<String, ?> uriVariables)
 			throws RestClientException {
 
@@ -422,6 +430,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T postForObject(URI url, @Nullable Object request, Class<T> responseType) throws RestClientException {
 		RequestCallback requestCallback = httpEntityCallback(request, responseType);
 		HttpMessageConverterExtractor<T> responseExtractor =
@@ -479,6 +488,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	// PATCH
 
 	@Override
+	@Nullable
 	public <T> T patchForObject(String url, @Nullable Object request, Class<T> responseType,
 			Object... uriVariables) throws RestClientException {
 
@@ -489,6 +499,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T patchForObject(String url, @Nullable Object request, Class<T> responseType,
 			Map<String, ?> uriVariables) throws RestClientException {
 
@@ -499,6 +510,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T patchForObject(URI url, @Nullable Object request, Class<T> responseType)
 			throws RestClientException {
 
@@ -637,6 +649,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	// general execution
 
 	@Override
+	@Nullable
 	public <T> T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback,
 			@Nullable ResponseExtractor<T> responseExtractor, Object... uriVariables) throws RestClientException {
 
@@ -645,6 +658,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback,
 			@Nullable ResponseExtractor<T> responseExtractor, Map<String, ?> uriVariables) throws RestClientException {
 
@@ -653,6 +667,7 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 	}
 
 	@Override
+	@Nullable
 	public <T> T execute(URI url, @Nullable HttpMethod method, @Nullable RequestCallback requestCallback,
 			@Nullable ResponseExtractor<T> responseExtractor) throws RestClientException {
 
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/AbstractRequestAttributesScope.java b/spring-web/src/main/java/org/springframework/web/context/request/AbstractRequestAttributesScope.java
index 6c7285d7979..0a16dee7e57 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/AbstractRequestAttributesScope.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/AbstractRequestAttributesScope.java
@@ -18,6 +18,7 @@ package org.springframework.web.context.request;
 
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.config.Scope;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -58,6 +59,7 @@ public abstract class AbstractRequestAttributesScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
 		Object scopedObject = attributes.getAttribute(name, getScope());
@@ -77,6 +79,7 @@ public abstract class AbstractRequestAttributesScope implements Scope {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveContextualObject(String key) {
 		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
 		return attributes.resolveReference(key);
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java b/spring-web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java
index 96daadd01a3..bcda6fa2ff1 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java
@@ -82,11 +82,13 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 
 
 	@Override
+	@Nullable
 	public String getHeader(String headerName) {
 		return getExternalContext().getRequestHeaderMap().get(headerName);
 	}
 
 	@Override
+	@Nullable
 	public String[] getHeaderValues(String headerName) {
 		return getExternalContext().getRequestHeaderValuesMap().get(headerName);
 	}
@@ -97,6 +99,7 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 	}
 
 	@Override
+	@Nullable
 	public String getParameter(String paramName) {
 		return getExternalContext().getRequestParameterMap().get(paramName);
 	}
@@ -107,6 +110,7 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 	}
 
 	@Override
+	@Nullable
 	public String[] getParameterValues(String paramName) {
 		return getExternalContext().getRequestParameterValuesMap().get(paramName);
 	}
@@ -127,11 +131,13 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 	}
 
 	@Override
+	@Nullable
 	public String getRemoteUser() {
 		return getFacesContext().getExternalContext().getRemoteUser();
 	}
 
 	@Override
+	@Nullable
 	public Principal getUserPrincipal() {
 		return getFacesContext().getExternalContext().getUserPrincipal();
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/RequestScope.java b/spring-web/src/main/java/org/springframework/web/context/request/RequestScope.java
index 92b36f84ae8..46f17b50bd5 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/RequestScope.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/RequestScope.java
@@ -16,6 +16,8 @@
 
 package org.springframework.web.context.request;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Request-backed {@link org.springframework.beans.factory.config.Scope}
  * implementation.
@@ -47,6 +49,7 @@ public class RequestScope extends AbstractRequestAttributesScope {
 	 * returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	public String getConversationId() {
 		return null;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java b/spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java
index 42dd0140262..0161000aac0 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java
@@ -132,11 +132,13 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 	}
 
 	@Override
+	@Nullable
 	public String getHeader(String headerName) {
 		return getRequest().getHeader(headerName);
 	}
 
 	@Override
+	@Nullable
 	public String[] getHeaderValues(String headerName) {
 		String[] headerValues = StringUtils.toStringArray(getRequest().getHeaders(headerName));
 		return (!ObjectUtils.isEmpty(headerValues) ? headerValues : null);
@@ -148,11 +150,13 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 	}
 
 	@Override
+	@Nullable
 	public String getParameter(String paramName) {
 		return getRequest().getParameter(paramName);
 	}
 
 	@Override
+	@Nullable
 	public String[] getParameterValues(String paramName) {
 		return getRequest().getParameterValues(paramName);
 	}
@@ -178,11 +182,13 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 	}
 
 	@Override
+	@Nullable
 	public String getRemoteUser() {
 		return getRequest().getRemoteUser();
 	}
 
 	@Override
+	@Nullable
 	public Principal getUserPrincipal() {
 		return getRequest().getUserPrincipal();
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/SessionScope.java b/spring-web/src/main/java/org/springframework/web/context/request/SessionScope.java
index 8d6a6e5fea7..52b799539f5 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/SessionScope.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/SessionScope.java
@@ -17,6 +17,7 @@
 package org.springframework.web.context.request;
 
 import org.springframework.beans.factory.ObjectFactory;
+import org.springframework.lang.Nullable;
 
 /**
  * Session-backed {@link org.springframework.beans.factory.config.Scope}
@@ -58,6 +59,7 @@ public class SessionScope extends AbstractRequestAttributesScope {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		Object mutex = RequestContextHolder.currentRequestAttributes().getSessionMutex();
 		synchronized (mutex) {
diff --git a/spring-web/src/main/java/org/springframework/web/context/request/async/DeferredResult.java b/spring-web/src/main/java/org/springframework/web/context/request/async/DeferredResult.java
index 71b100304ae..2b4551caae6 100644
--- a/spring-web/src/main/java/org/springframework/web/context/request/async/DeferredResult.java
+++ b/spring-web/src/main/java/org/springframework/web/context/request/async/DeferredResult.java
@@ -56,6 +56,7 @@ public class DeferredResult<T> {
 	private static final Log logger = LogFactory.getLog(DeferredResult.class);
 
 
+	@Nullable
 	private final Long timeout;
 
 	private final Object timeoutResult;
@@ -138,6 +139,7 @@ public class DeferredResult<T> {
 	/**
 	 * Return the configured timeout value in milliseconds.
 	 */
+	@Nullable
 	final Long getTimeoutValue() {
 		return this.timeout;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/AbstractRefreshableWebApplicationContext.java b/spring-web/src/main/java/org/springframework/web/context/support/AbstractRefreshableWebApplicationContext.java
index e6f4266cab7..9911abdaffc 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/AbstractRefreshableWebApplicationContext.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/AbstractRefreshableWebApplicationContext.java
@@ -214,6 +214,7 @@ public abstract class AbstractRefreshableWebApplicationContext extends AbstractR
 	}
 
 	@Override
+	@Nullable
 	public Theme getTheme(String themeName) {
 		Assert.state(this.themeSource != null, "No ThemeSource available");
 		return this.themeSource.getTheme(themeName);
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ContextExposingHttpServletRequest.java b/spring-web/src/main/java/org/springframework/web/context/support/ContextExposingHttpServletRequest.java
index 34ccda3b29d..86244d7abb7 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ContextExposingHttpServletRequest.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ContextExposingHttpServletRequest.java
@@ -80,6 +80,7 @@ public class ContextExposingHttpServletRequest extends HttpServletRequestWrapper
 
 
 	@Override
+	@Nullable
 	public Object getAttribute(String name) {
 		if ((this.explicitAttributes == null || !this.explicitAttributes.contains(name)) &&
 				(this.exposedContextBeanNames == null || this.exposedContextBeanNames.contains(name)) &&
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/GenericWebApplicationContext.java b/spring-web/src/main/java/org/springframework/web/context/support/GenericWebApplicationContext.java
index 7a09d567f66..ff16148474a 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/GenericWebApplicationContext.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/GenericWebApplicationContext.java
@@ -197,6 +197,7 @@ public class GenericWebApplicationContext extends GenericApplicationContext
 	}
 
 	@Override
+	@Nullable
 	public Theme getTheme(String themeName) {
 		Assert.state(this.themeSource != null, "No ThemeSource available");
 		return this.themeSource.getTheme(themeName);
@@ -213,6 +214,7 @@ public class GenericWebApplicationContext extends GenericApplicationContext
 	}
 
 	@Override
+	@Nullable
 	public ServletConfig getServletConfig() {
 		throw new UnsupportedOperationException(
 				"GenericWebApplicationContext does not support getServletConfig()");
@@ -224,6 +226,7 @@ public class GenericWebApplicationContext extends GenericApplicationContext
 	}
 
 	@Override
+	@Nullable
 	public String getNamespace() {
 		throw new UnsupportedOperationException(
 				"GenericWebApplicationContext does not support getNamespace()");
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletConfigPropertySource.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletConfigPropertySource.java
index 212b9a302df..19d43f1417f 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletConfigPropertySource.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletConfigPropertySource.java
@@ -20,6 +20,7 @@ import javax.servlet.ServletConfig;
 
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.PropertySource;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -41,6 +42,7 @@ public class ServletConfigPropertySource extends EnumerablePropertySource<Servle
 	}
 
 	@Override
+	@Nullable
 	public String getProperty(String name) {
 		return this.source.getInitParameter(name);
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextAttributeFactoryBean.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextAttributeFactoryBean.java
index 8e42e573dc1..5ffa436c56e 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextAttributeFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextAttributeFactoryBean.java
@@ -71,6 +71,7 @@ public class ServletContextAttributeFactoryBean implements FactoryBean<Object>,
 
 
 	@Override
+	@Nullable
 	public Object getObject() throws Exception {
 		return this.attribute;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextParameterFactoryBean.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextParameterFactoryBean.java
index 73cfbbbeae4..e0c853badd0 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextParameterFactoryBean.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextParameterFactoryBean.java
@@ -66,6 +66,7 @@ public class ServletContextParameterFactoryBean implements FactoryBean<String>,
 
 
 	@Override
+	@Nullable
 	public String getObject() {
 		return this.paramValue;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextPropertySource.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextPropertySource.java
index 0fb48c9e5a1..eb15fbe2474 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextPropertySource.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextPropertySource.java
@@ -20,6 +20,7 @@ import javax.servlet.ServletContext;
 
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.PropertySource;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
@@ -41,6 +42,7 @@ public class ServletContextPropertySource extends EnumerablePropertySource<Servl
 	}
 
 	@Override
+	@Nullable
 	public String getProperty(String name) {
 		return this.source.getInitParameter(name);
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextResource.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextResource.java
index 758c2755f50..20aea916d4d 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextResource.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextResource.java
@@ -28,6 +28,7 @@ import javax.servlet.ServletContext;
 import org.springframework.core.io.AbstractFileResolvingResource;
 import org.springframework.core.io.ContextResource;
 import org.springframework.core.io.Resource;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ResourceUtils;
 import org.springframework.util.StringUtils;
@@ -212,6 +213,7 @@ public class ServletContextResource extends AbstractFileResolvingResource implem
 	 * @see org.springframework.util.StringUtils#getFilename(String)
 	 */
 	@Override
+	@Nullable
 	public String getFilename() {
 		return StringUtils.getFilename(this.path);
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextScope.java b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextScope.java
index fcbe1e7ca4d..b550de66af2 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/ServletContextScope.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/ServletContextScope.java
@@ -23,6 +23,7 @@ import javax.servlet.ServletContext;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.config.Scope;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -74,6 +75,7 @@ public class ServletContextScope implements Scope, DisposableBean {
 	}
 
 	@Override
+	@Nullable
 	public Object remove(String name) {
 		Object scopedObject = this.servletContext.getAttribute(name);
 		if (scopedObject != null) {
@@ -92,11 +94,13 @@ public class ServletContextScope implements Scope, DisposableBean {
 	}
 
 	@Override
+	@Nullable
 	public Object resolveContextualObject(String key) {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public String getConversationId() {
 		return null;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/context/support/StaticWebApplicationContext.java b/spring-web/src/main/java/org/springframework/web/context/support/StaticWebApplicationContext.java
index 0d133f164af..8903f22cbfc 100644
--- a/spring-web/src/main/java/org/springframework/web/context/support/StaticWebApplicationContext.java
+++ b/spring-web/src/main/java/org/springframework/web/context/support/StaticWebApplicationContext.java
@@ -197,6 +197,7 @@ public class StaticWebApplicationContext extends StaticApplicationContext
 	}
 
 	@Override
+	@Nullable
 	public Theme getTheme(String themeName) {
 		Assert.state(this.themeSource != null, "No ThemeSource available");
 		return this.themeSource.getTheme(themeName);
diff --git a/spring-web/src/main/java/org/springframework/web/cors/UrlBasedCorsConfigurationSource.java b/spring-web/src/main/java/org/springframework/web/cors/UrlBasedCorsConfigurationSource.java
index 50ca5b1d3f7..63b546fe8e2 100644
--- a/spring-web/src/main/java/org/springframework/web/cors/UrlBasedCorsConfigurationSource.java
+++ b/spring-web/src/main/java/org/springframework/web/cors/UrlBasedCorsConfigurationSource.java
@@ -115,6 +115,7 @@ public class UrlBasedCorsConfigurationSource implements CorsConfigurationSource
 
 
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 		String lookupPath = this.urlPathHelper.getLookupPathForRequest(request);
 		for (Map.Entry<String, CorsConfiguration> entry : this.corsConfigurations.entrySet()) {
diff --git a/spring-web/src/main/java/org/springframework/web/cors/reactive/UrlBasedCorsConfigurationSource.java b/spring-web/src/main/java/org/springframework/web/cors/reactive/UrlBasedCorsConfigurationSource.java
index 59400e00566..5dfb7c771b1 100644
--- a/spring-web/src/main/java/org/springframework/web/cors/reactive/UrlBasedCorsConfigurationSource.java
+++ b/spring-web/src/main/java/org/springframework/web/cors/reactive/UrlBasedCorsConfigurationSource.java
@@ -66,6 +66,7 @@ public class UrlBasedCorsConfigurationSource implements CorsConfigurationSource
 	}
 
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(ServerWebExchange exchange) {
 		PathContainer lookupPath = exchange.getRequest().getPath().pathWithinApplication();
 		return this.corsConfigurations.entrySet().stream()
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java
index 49ab8001672..8c259972868 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java
@@ -90,6 +90,7 @@ public abstract class AbstractNamedValueMethodArgumentResolver implements Handle
 
 
 	@Override
+	@Nullable
 	public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractWebArgumentResolverAdapter.java b/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractWebArgumentResolverAdapter.java
index 78a492230ca..9dcdb9cd130 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractWebArgumentResolverAdapter.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/AbstractWebArgumentResolverAdapter.java
@@ -92,6 +92,7 @@ public abstract class AbstractWebArgumentResolverAdapter implements HandlerMetho
 	 * to the method parameter.
 	 */
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/ErrorsMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/ErrorsMethodArgumentResolver.java
index 4d247d6853c..7928ab8d7ba 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/ErrorsMethodArgumentResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/ErrorsMethodArgumentResolver.java
@@ -49,6 +49,7 @@ public class ErrorsMethodArgumentResolver implements HandlerMethodArgumentResolv
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/ExpressionValueMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/ExpressionValueMethodArgumentResolver.java
index f1c1c6abf43..8cff466b95f 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/ExpressionValueMethodArgumentResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/ExpressionValueMethodArgumentResolver.java
@@ -64,6 +64,7 @@ public class ExpressionValueMethodArgumentResolver extends AbstractNamedValueMet
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest webRequest) throws Exception {
 		// No name to resolve
 		return null;
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/MapMethodProcessor.java b/spring-web/src/main/java/org/springframework/web/method/annotation/MapMethodProcessor.java
index 6054517512a..a21dd236570 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/MapMethodProcessor.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/MapMethodProcessor.java
@@ -46,6 +46,7 @@ public class MapMethodProcessor implements HandlerMethodArgumentResolver, Handle
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/ModelAttributeMethodProcessor.java b/spring-web/src/main/java/org/springframework/web/method/annotation/ModelAttributeMethodProcessor.java
index f35e2619984..5114cbd0c2d 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/ModelAttributeMethodProcessor.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/ModelAttributeMethodProcessor.java
@@ -107,6 +107,7 @@ public class ModelAttributeMethodProcessor implements HandlerMethodArgumentResol
 	 * @throws Exception if WebDataBinder initialization fails
 	 */
 	@Override
+	@Nullable
 	public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/ModelMethodProcessor.java b/spring-web/src/main/java/org/springframework/web/method/annotation/ModelMethodProcessor.java
index ea0aacde818..dc690b6a1e4 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/ModelMethodProcessor.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/ModelMethodProcessor.java
@@ -45,6 +45,7 @@ public class ModelMethodProcessor implements HandlerMethodArgumentResolver, Hand
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java
index c2574af25f2..ad8064eaf33 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java
@@ -69,6 +69,7 @@ public class RequestHeaderMethodArgumentResolver extends AbstractNamedValueMetho
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
 		String[] headerValues = request.getHeaderValues(name);
 		if (headerValues != null) {
diff --git a/spring-web/src/main/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolver.java b/spring-web/src/main/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolver.java
index 9da01d15a55..20e2513374b 100644
--- a/spring-web/src/main/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolver.java
@@ -156,6 +156,7 @@ public class RequestParamMethodArgumentResolver extends AbstractNamedValueMethod
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
 		HttpServletRequest servletRequest = request.getNativeRequest(HttpServletRequest.class);
 
diff --git a/spring-web/src/main/java/org/springframework/web/method/support/HandlerMethodArgumentResolverComposite.java b/spring-web/src/main/java/org/springframework/web/method/support/HandlerMethodArgumentResolverComposite.java
index 269659b3e8c..130f616f148 100644
--- a/spring-web/src/main/java/org/springframework/web/method/support/HandlerMethodArgumentResolverComposite.java
+++ b/spring-web/src/main/java/org/springframework/web/method/support/HandlerMethodArgumentResolverComposite.java
@@ -111,6 +111,7 @@ public class HandlerMethodArgumentResolverComposite implements HandlerMethodArgu
 	 * @throws IllegalStateException if no suitable {@link HandlerMethodArgumentResolver} is found.
 	 */
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-web/src/main/java/org/springframework/web/server/ResponseStatusException.java b/spring-web/src/main/java/org/springframework/web/server/ResponseStatusException.java
index ba77322bc41..0346e49c4cf 100644
--- a/spring-web/src/main/java/org/springframework/web/server/ResponseStatusException.java
+++ b/spring-web/src/main/java/org/springframework/web/server/ResponseStatusException.java
@@ -87,6 +87,7 @@ public class ResponseStatusException extends NestedRuntimeException {
 	}
 
 	@Override
+	@Nullable
 	public String getMessage() {
 		String msg = "Response status " + this.status + (this.reason != null ? " with reason \"" + reason + "\"" : "");
 		return NestedExceptionUtils.buildMessage(msg, getCause());
diff --git a/spring-web/src/main/java/org/springframework/web/server/i18n/FixedLocaleContextResolver.java b/spring-web/src/main/java/org/springframework/web/server/i18n/FixedLocaleContextResolver.java
index 1930e9c4571..0ddd3dc558e 100644
--- a/spring-web/src/main/java/org/springframework/web/server/i18n/FixedLocaleContextResolver.java
+++ b/spring-web/src/main/java/org/springframework/web/server/i18n/FixedLocaleContextResolver.java
@@ -79,6 +79,7 @@ public class FixedLocaleContextResolver implements LocaleContextResolver {
 				return locale;
 			}
 			@Override
+			@Nullable
 			public TimeZone getTimeZone() {
 				return timeZone;
 			}
diff --git a/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java b/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
index 432709b43d7..f251d918290 100644
--- a/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
+++ b/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
@@ -105,6 +105,7 @@ final class HierarchicalUriComponents extends UriComponents {
 	// Component getters
 
 	@Override
+	@Nullable
 	public String getSchemeSpecificPart() {
 		return null;
 	}
@@ -144,6 +145,7 @@ final class HierarchicalUriComponents extends UriComponents {
 	}
 
 	@Override
+	@Nullable
 	public String getQuery() {
 		if (!this.queryParams.isEmpty()) {
 			StringBuilder queryBuilder = new StringBuilder();
diff --git a/spring-web/src/main/java/org/springframework/web/util/OpaqueUriComponents.java b/spring-web/src/main/java/org/springframework/web/util/OpaqueUriComponents.java
index 2abf8106023..ed7cd128592 100644
--- a/spring-web/src/main/java/org/springframework/web/util/OpaqueUriComponents.java
+++ b/spring-web/src/main/java/org/springframework/web/util/OpaqueUriComponents.java
@@ -51,16 +51,19 @@ final class OpaqueUriComponents extends UriComponents {
 
 
 	@Override
+	@Nullable
 	public String getSchemeSpecificPart() {
 		return this.ssp;
 	}
 
 	@Override
+	@Nullable
 	public String getUserInfo() {
 		return null;
 	}
 
 	@Override
+	@Nullable
 	public String getHost() {
 		return null;
 	}
@@ -71,6 +74,7 @@ final class OpaqueUriComponents extends UriComponents {
 	}
 
 	@Override
+	@Nullable
 	public String getPath() {
 		return null;
 	}
@@ -81,6 +85,7 @@ final class OpaqueUriComponents extends UriComponents {
 	}
 
 	@Override
+	@Nullable
 	public String getQuery() {
 		return null;
 	}
diff --git a/spring-web/src/main/java/org/springframework/web/util/ServletContextPropertyUtils.java b/spring-web/src/main/java/org/springframework/web/util/ServletContextPropertyUtils.java
index c018aa3a0b4..900ac6c800e 100644
--- a/spring-web/src/main/java/org/springframework/web/util/ServletContextPropertyUtils.java
+++ b/spring-web/src/main/java/org/springframework/web/util/ServletContextPropertyUtils.java
@@ -17,6 +17,7 @@ package org.springframework.web.util;
 
 import javax.servlet.ServletContext;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.PropertyPlaceholderHelper;
 import org.springframework.util.SystemPropertyUtils;
 
@@ -90,6 +91,7 @@ public abstract class ServletContextPropertyUtils {
         }
 
         @Override
+		@Nullable
 		public String resolvePlaceholder(String placeholderName) {
             try {
                 String propVal = this.servletContext.getInitParameter(placeholderName);
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java b/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java
index 44b179e2c10..7200a1b6be4 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ResourceHandlerFunction.java
@@ -30,6 +30,7 @@ import reactor.core.publisher.Mono;
 import org.springframework.core.io.Resource;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
+import org.springframework.lang.Nullable;
 import org.springframework.web.reactive.function.BodyInserters;
 
 /**
@@ -129,6 +130,7 @@ class ResourceHandlerFunction implements HandlerFunction<ServerResponse> {
 		}
 
 		@Override
+		@Nullable
 		public String getFilename() {
 			return this.delegate.getFilename();
 		}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/GzipResourceResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/GzipResourceResolver.java
index 950c4aa51c0..423e1d15651 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/GzipResourceResolver.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/GzipResourceResolver.java
@@ -88,18 +88,22 @@ public class GzipResourceResolver extends AbstractResourceResolver {
 			this.gzipped = original.createRelative(original.getFilename() + ".gz");
 		}
 
+		@Override
 		public InputStream getInputStream() throws IOException {
 			return this.gzipped.getInputStream();
 		}
 
+		@Override
 		public boolean exists() {
 			return this.gzipped.exists();
 		}
 
+		@Override
 		public boolean isReadable() {
 			return this.gzipped.isReadable();
 		}
 
+		@Override
 		public boolean isOpen() {
 			return this.gzipped.isOpen();
 		}
@@ -109,34 +113,43 @@ public class GzipResourceResolver extends AbstractResourceResolver {
 			return this.gzipped.isFile();
 		}
 
+		@Override
 		public URL getURL() throws IOException {
 			return this.gzipped.getURL();
 		}
 
+		@Override
 		public URI getURI() throws IOException {
 			return this.gzipped.getURI();
 		}
 
+		@Override
 		public File getFile() throws IOException {
 			return this.gzipped.getFile();
 		}
 
+		@Override
 		public long contentLength() throws IOException {
 			return this.gzipped.contentLength();
 		}
 
+		@Override
 		public long lastModified() throws IOException {
 			return this.gzipped.lastModified();
 		}
 
+		@Override
 		public Resource createRelative(String relativePath) throws IOException {
 			return this.gzipped.createRelative(relativePath);
 		}
 
+		@Override
+		@Nullable
 		public String getFilename() {
 			return this.original.getFilename();
 		}
 
+		@Override
 		public String getDescription() {
 			return this.gzipped.getDescription();
 		}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
index 256f8270d78..b022e54f454 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/VersionResourceResolver.java
@@ -302,6 +302,7 @@ public class VersionResourceResolver extends AbstractResourceResolver {
 		}
 
 		@Override
+		@Nullable
 		public String getFilename() {
 			return this.original.getFilename();
 		}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractNameValueExpression.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractNameValueExpression.java
index c144dca8dd5..071929c7bd0 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractNameValueExpression.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractNameValueExpression.java
@@ -16,6 +16,7 @@
 
 package org.springframework.web.reactive.result.condition;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.server.ServerWebExchange;
 
 /**
@@ -30,6 +31,7 @@ abstract class AbstractNameValueExpression<T> implements NameValueExpression<T>
 
 	protected final String name;
 
+	@Nullable
 	protected final T value;
 
 	protected final boolean isNegated;
@@ -54,6 +56,7 @@ abstract class AbstractNameValueExpression<T> implements NameValueExpression<T>
 	}
 
 	@Override
+	@Nullable
 	public T getValue() {
 		return this.value;
 	}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/HeadersRequestCondition.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/HeadersRequestCondition.java
index 4fc3784611e..c29fe70ead2 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/HeadersRequestCondition.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/HeadersRequestCondition.java
@@ -21,6 +21,7 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.cors.reactive.CorsUtils;
 import org.springframework.web.server.ServerWebExchange;
@@ -107,6 +108,7 @@ public final class HeadersRequestCondition extends AbstractRequestCondition<Head
 	 * or {@code null} otherwise.
 	 */
 	@Override
+	@Nullable
 	public HeadersRequestCondition getMatchingCondition(ServerWebExchange exchange) {
 		if (CorsUtils.isPreFlightRequest(exchange.getRequest())) {
 			return PRE_FLIGHT_MATCH;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/NameValueExpression.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/NameValueExpression.java
index d4403b4f9c2..f00ac152e02 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/NameValueExpression.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/NameValueExpression.java
@@ -16,6 +16,8 @@
 
 package org.springframework.web.reactive.result.condition;
 
+import org.springframework.lang.Nullable;
+
 /**
  * A contract for {@code "name!=value"} style expression used to specify request
  * parameters and request header conditions in {@code @RequestMapping}.
@@ -27,6 +29,7 @@ public interface NameValueExpression<T> {
 
 	String getName();
 
+	@Nullable
 	T getValue();
 
 	boolean isNegated();
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/ProducesRequestCondition.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/ProducesRequestCondition.java
index 887ab360653..fd6285d9354 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/ProducesRequestCondition.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/ProducesRequestCondition.java
@@ -25,6 +25,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.cors.reactive.CorsUtils;
@@ -181,6 +182,7 @@ public final class ProducesRequestCondition extends AbstractRequestCondition<Pro
 	 * or {@code null} if no expressions match.
 	 */
 	@Override
+	@Nullable
 	public ProducesRequestCondition getMatchingCondition(ServerWebExchange exchange) {
 		if (CorsUtils.isPreFlightRequest(exchange.getRequest())) {
 			return PRE_FLIGHT_MATCH;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/RequestMethodsRequestCondition.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/RequestMethodsRequestCondition.java
index c96b2aefffe..8256867f67d 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/RequestMethodsRequestCondition.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/RequestMethodsRequestCondition.java
@@ -103,6 +103,7 @@ public final class RequestMethodsRequestCondition extends AbstractRequestConditi
 	 * request method is OPTIONS.
 	 */
 	@Override
+	@Nullable
 	public RequestMethodsRequestCondition getMatchingCondition(ServerWebExchange exchange) {
 		if (CorsUtils.isPreFlightRequest(exchange.getRequest())) {
 			return matchPreFlight(exchange.getRequest());
@@ -129,6 +130,7 @@ public final class RequestMethodsRequestCondition extends AbstractRequestConditi
 		return matchRequestMethod(expectedMethod);
 	}
 
+	@Nullable
 	private RequestMethodsRequestCondition matchRequestMethod(@Nullable HttpMethod httpMethod) {
 		if (httpMethod != null) {
 			for (RequestMethod method : getMethods()) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfo.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfo.java
index e383a6105b6..7174b7d2a61 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfo.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfo.java
@@ -189,6 +189,7 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 				methods, params, headers, consumes, produces, custom.getCondition());
 	}
 
+	@Nullable
 	private String combineNames(RequestMappingInfo other) {
 		if (this.name != null && other.name != null) {
 			String separator = "#";
@@ -210,6 +211,7 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 	 * @return a new instance in case all conditions match; or {@code null} otherwise
 	 */
 	@Override
+	@Nullable
 	public RequestMappingInfo getMatchingCondition(ServerWebExchange exchange) {
 		RequestMethodsRequestCondition methods = this.methodsCondition.getMatchingCondition(exchange);
 		ParamsRequestCondition params = this.paramsCondition.getMatchingCondition(exchange);
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/Rendering.java b/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/Rendering.java
index 0cbcfb43d73..9cab3ff5e2d 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/Rendering.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/result/view/Rendering.java
@@ -46,7 +46,6 @@ public interface Rendering {
 	/**
 	 * Return the selected {@link String} view name or {@link View} object.
 	 */
-	@Nullable
 	Object view();
 
 	/**
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/AbstractListenerWebSocketSession.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/AbstractListenerWebSocketSession.java
index a4d8e4f825b..a55a0331843 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/AbstractListenerWebSocketSession.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/AbstractListenerWebSocketSession.java
@@ -224,6 +224,7 @@ public abstract class AbstractListenerWebSocketSession<T> extends AbstractWebSoc
 		}
 
 		@Override
+		@Nullable
 		protected WebSocketMessage read() throws IOException {
 			if (this.webSocketMessage != null) {
 				WebSocketMessage result = this.webSocketMessage;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java
index 0cfb7cf130e..c95529eddff 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java
@@ -188,6 +188,7 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);
 		XmlReaderContext readerContext = parserContext.getReaderContext();
@@ -706,6 +707,7 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 		}
 
 		@Override
+		@Nullable
 		public CompositeUriComponentsContributor getObject() throws Exception {
 			return this.uriComponentsContributor;
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/CorsBeanDefinitionParser.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/CorsBeanDefinitionParser.java
index 3c72593b020..68df4124509 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/CorsBeanDefinitionParser.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/CorsBeanDefinitionParser.java
@@ -26,6 +26,7 @@ import org.w3c.dom.Element;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 import org.springframework.util.xml.DomUtils;
 import org.springframework.web.cors.CorsConfiguration;
@@ -42,6 +43,7 @@ import org.springframework.web.cors.CorsConfiguration;
 public class CorsBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 
 		Map<String, CorsConfiguration> corsConfigurations = new LinkedHashMap<>();
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/DefaultServletHandlerBeanDefinitionParser.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/DefaultServletHandlerBeanDefinitionParser.java
index 4851b9dd1dd..0fa2ba7cad5 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/DefaultServletHandlerBeanDefinitionParser.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/DefaultServletHandlerBeanDefinitionParser.java
@@ -26,6 +26,7 @@ import org.springframework.beans.factory.support.ManagedMap;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter;
@@ -44,6 +45,7 @@ import org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler
 class DefaultServletHandlerBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		Object source = parserContext.extractSource(element);
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/InterceptorsBeanDefinitionParser.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/InterceptorsBeanDefinitionParser.java
index 7c631e50e89..e62c80b58b9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/InterceptorsBeanDefinitionParser.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/InterceptorsBeanDefinitionParser.java
@@ -28,6 +28,7 @@ import org.springframework.beans.factory.support.ManagedList;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.xml.DomUtils;
 import org.springframework.web.servlet.handler.MappedInterceptor;
 
@@ -41,6 +42,7 @@ import org.springframework.web.servlet.handler.MappedInterceptor;
 class InterceptorsBeanDefinitionParser implements BeanDefinitionParser {
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 		CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
 		parserContext.pushContainingComponent(compDefinition);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.java
index 2c181c594b4..624beb151c9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.java
@@ -22,6 +22,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.format.FormatterRegistry;
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
@@ -133,11 +134,13 @@ public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {
 	}
 
 	@Override
+	@Nullable
 	protected Validator getValidator() {
 		return this.configurers.getValidator();
 	}
 
 	@Override
+	@Nullable
 	protected MessageCodesResolver getMessageCodesResolver() {
 		return this.configurers.getMessageCodesResolver();
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerAdapter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerAdapter.java
index 0270046e605..40d90055b60 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerAdapter.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerAdapter.java
@@ -20,6 +20,7 @@ import java.util.List;
 
 import org.springframework.format.FormatterRegistry;
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.lang.Nullable;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
@@ -172,6 +173,7 @@ public abstract class WebMvcConfigurerAdapter implements WebMvcConfigurer {
 	 * <p>This implementation returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	public Validator getValidator() {
 		return null;
 	}
@@ -181,6 +183,7 @@ public abstract class WebMvcConfigurerAdapter implements WebMvcConfigurer {
 	 * <p>This implementation returns {@code null}.
 	 */
 	@Override
+	@Nullable
 	public MessageCodesResolver getMessageCodesResolver() {
 		return null;
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java
index cdbb0a347d2..79e0af74724 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java
@@ -21,6 +21,7 @@ import java.util.List;
 
 import org.springframework.format.FormatterRegistry;
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
@@ -175,6 +176,7 @@ class WebMvcConfigurerComposite implements WebMvcConfigurer {
 	}
 
 	@Override
+	@Nullable
 	public MessageCodesResolver getMessageCodesResolver() {
 		MessageCodesResolver selected = null;
 		for (WebMvcConfigurer configurer : this.delegates) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractDetectingUrlHandlerMapping.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractDetectingUrlHandlerMapping.java
index 5c7b007db84..132ff4a8fdb 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractDetectingUrlHandlerMapping.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractDetectingUrlHandlerMapping.java
@@ -20,7 +20,6 @@ import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextException;
-import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -96,10 +95,8 @@ public abstract class AbstractDetectingUrlHandlerMapping extends AbstractUrlHand
 	/**
 	 * Determine the URLs for the given handler bean.
 	 * @param beanName the name of the candidate bean
-	 * @return the URLs determined for the bean,
-	 * or {@code null} or an empty array if none
+	 * @return the URLs determined for the bean, or an empty array if none
 	 */
-	@Nullable
 	protected abstract String[] determineUrlsForHandler(String beanName);
 
 }
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerExceptionResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerExceptionResolver.java
index ff358d11e21..997c786cadc 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerExceptionResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerExceptionResolver.java
@@ -128,6 +128,7 @@ public abstract class AbstractHandlerExceptionResolver implements HandlerExcepti
 	 * to the {@link #doResolveException} template method.
 	 */
 	@Override
+	@Nullable
 	public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response,
 			@Nullable Object handler, Exception ex) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMapping.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMapping.java
index 26ed9b2e519..0cf6e2d19e0 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMapping.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMapping.java
@@ -346,6 +346,7 @@ public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport
 	 * @see #getHandlerInternal
 	 */
 	@Override
+	@Nullable
 	public final HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
 		Object handler = getHandlerInternal(request);
 		if (handler == null) {
@@ -488,6 +489,7 @@ public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport
 		}
 
 		@Override
+		@Nullable
 		public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 			return this.config;
 		}
@@ -511,6 +513,7 @@ public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport
 		}
 
 		@Override
+		@Nullable
 		public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 			return this.config;
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodExceptionResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodExceptionResolver.java
index 9c45e42b474..5ce8523fe1a 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodExceptionResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodExceptionResolver.java
@@ -54,6 +54,7 @@ public abstract class AbstractHandlerMethodExceptionResolver extends AbstractHan
 	}
 
 	@Override
+	@Nullable
 	protected final ModelAndView doResolveException(
 			HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractUrlHandlerMapping.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractUrlHandlerMapping.java
index cc186b613b3..4bc981f872c 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractUrlHandlerMapping.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractUrlHandlerMapping.java
@@ -294,6 +294,7 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping i
 	}
 
 	@Override
+	@Nullable
 	public RequestMatchResult match(HttpServletRequest request, String pattern) {
 		String lookupPath = getUrlPathHelper().getLookupPathForRequest(request);
 		if (getPathMatcher().match(pattern, lookupPath)) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java
index 4b38e361a8d..905e876955f 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerMappingIntrospector.java
@@ -144,6 +144,7 @@ public class HandlerMappingIntrospector implements CorsConfigurationSource {
 	}
 
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 		HttpServletRequest wrapper = new RequestAttributeChangeIgnoringWrapper(request);
 		for (HandlerMapping handlerMapping : this.handlerMappings) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleMappingExceptionResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleMappingExceptionResolver.java
index 4f98dd66e58..bd2dd435bba 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleMappingExceptionResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleMappingExceptionResolver.java
@@ -179,6 +179,7 @@ public class SimpleMappingExceptionResolver extends AbstractHandlerExceptionReso
 	 * @return a corresponding ModelAndView to forward to, or {@code null} for default processing
 	 */
 	@Override
+	@Nullable
 	protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,
 			@Nullable Object handler, Exception ex) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletHandlerAdapter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletHandlerAdapter.java
index e19ebe57f0c..734482f9662 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletHandlerAdapter.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletHandlerAdapter.java
@@ -20,6 +20,7 @@ import javax.servlet.Servlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.ModelAndView;
 
@@ -59,6 +60,7 @@ public class SimpleServletHandlerAdapter implements HandlerAdapter {
 	}
 
 	@Override
+	@Nullable
 	public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
 			throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/CookieLocaleResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/CookieLocaleResolver.java
index 5f398af2567..e119d6791f1 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/CookieLocaleResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/CookieLocaleResolver.java
@@ -168,10 +168,12 @@ public class CookieLocaleResolver extends CookieGenerator implements LocaleConte
 		parseLocaleCookieIfNecessary(request);
 		return new TimeZoneAwareLocaleContext() {
 			@Override
+			@Nullable
 			public Locale getLocale() {
 				return (Locale) request.getAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME);
 			}
 			@Override
+			@Nullable
 			public TimeZone getTimeZone() {
 				return (TimeZone) request.getAttribute(TIME_ZONE_REQUEST_ATTRIBUTE_NAME);
 			}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/FixedLocaleResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/FixedLocaleResolver.java
index 6596c50ccd2..a7a20e88999 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/FixedLocaleResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/FixedLocaleResolver.java
@@ -82,6 +82,7 @@ public class FixedLocaleResolver extends AbstractLocaleContextResolver {
 	public LocaleContext resolveLocaleContext(HttpServletRequest request) {
 		return new TimeZoneAwareLocaleContext() {
 			@Override
+			@Nullable
 			public Locale getLocale() {
 				return getDefaultLocale();
 			}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/SessionLocaleResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/SessionLocaleResolver.java
index 0a4516cf537..18bbb984115 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/SessionLocaleResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/SessionLocaleResolver.java
@@ -127,6 +127,7 @@ public class SessionLocaleResolver extends AbstractLocaleContextResolver {
 				return locale;
 			}
 			@Override
+			@Nullable
 			public TimeZone getTimeZone() {
 				TimeZone timeZone = (TimeZone) WebUtils.getSessionAttribute(request, timeZoneAttributeName);
 				if (timeZone == null) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/AbstractController.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/AbstractController.java
index e742af2e425..ffdef0e84ce 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/AbstractController.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/AbstractController.java
@@ -149,6 +149,7 @@ public abstract class AbstractController extends WebContentGenerator implements
 
 
 	@Override
+	@Nullable
 	public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)
 			throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/HttpRequestHandlerAdapter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/HttpRequestHandlerAdapter.java
index 7c6f8349cba..cac1e47ddf4 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/HttpRequestHandlerAdapter.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/HttpRequestHandlerAdapter.java
@@ -19,6 +19,7 @@ package org.springframework.web.servlet.mvc;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.HttpRequestHandler;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.ModelAndView;
@@ -45,6 +46,7 @@ public class HttpRequestHandlerAdapter implements HandlerAdapter {
 	}
 
 	@Override
+	@Nullable
 	public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
 			throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/SimpleControllerHandlerAdapter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/SimpleControllerHandlerAdapter.java
index bcd28c0e540..7a2627068a4 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/SimpleControllerHandlerAdapter.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/SimpleControllerHandlerAdapter.java
@@ -19,6 +19,7 @@ package org.springframework.web.servlet.mvc;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.ModelAndView;
 
@@ -44,6 +45,7 @@ public class SimpleControllerHandlerAdapter implements HandlerAdapter {
 	}
 
 	@Override
+	@Nullable
 	public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
 			throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/ResponseStatusExceptionResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/ResponseStatusExceptionResolver.java
index 167fe78565c..a064fe856c9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/ResponseStatusExceptionResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/ResponseStatusExceptionResolver.java
@@ -66,6 +66,7 @@ public class ResponseStatusExceptionResolver extends AbstractHandlerExceptionRes
 
 
 	@Override
+	@Nullable
 	protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,
 			@Nullable Object handler, Exception ex) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/CompositeRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/CompositeRequestCondition.java
index 2ea4dd26f2f..3db4d6eb9d2 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/CompositeRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/CompositeRequestCondition.java
@@ -23,6 +23,7 @@ import java.util.List;
 
 import javax.servlet.http.HttpServletRequest;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
@@ -142,6 +143,7 @@ public class CompositeRequestCondition extends AbstractRequestCondition<Composit
 	 * <p>An empty {@code CompositeRequestCondition} matches to all requests.
 	 */
 	@Override
+	@Nullable
 	public CompositeRequestCondition getMatchingCondition(HttpServletRequest request) {
 		if (isEmpty()) {
 			return this;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ConsumesRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ConsumesRequestCondition.java
index d569bddb6ec..83e10c42a68 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ConsumesRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ConsumesRequestCondition.java
@@ -161,6 +161,7 @@ public final class ConsumesRequestCondition extends AbstractRequestCondition<Con
 	 * or {@code null} if no expressions match.
 	 */
 	@Override
+	@Nullable
 	public ConsumesRequestCondition getMatchingCondition(HttpServletRequest request) {
 		if (CorsUtils.isPreFlightRequest(request)) {
 			return PRE_FLIGHT_MATCH;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/HeadersRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/HeadersRequestCondition.java
index f76658d1475..78ad24eaf98 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/HeadersRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/HeadersRequestCondition.java
@@ -22,6 +22,7 @@ import java.util.LinkedHashSet;
 import java.util.Set;
 import javax.servlet.http.HttpServletRequest;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.cors.CorsUtils;
@@ -107,6 +108,7 @@ public final class HeadersRequestCondition extends AbstractRequestCondition<Head
 	 * or {@code null} otherwise.
 	 */
 	@Override
+	@Nullable
 	public HeadersRequestCondition getMatchingCondition(HttpServletRequest request) {
 		if (CorsUtils.isPreFlightRequest(request)) {
 			return PRE_FLIGHT_MATCH;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ParamsRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ParamsRequestCondition.java
index ea4eda80808..9d24c7aa0d7 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ParamsRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ParamsRequestCondition.java
@@ -22,6 +22,7 @@ import java.util.LinkedHashSet;
 import java.util.Set;
 import javax.servlet.http.HttpServletRequest;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.util.WebUtils;
@@ -95,6 +96,7 @@ public final class ParamsRequestCondition extends AbstractRequestCondition<Param
 	 * or {@code null} otherwise.
 	 */
 	@Override
+	@Nullable
 	public ParamsRequestCondition getMatchingCondition(HttpServletRequest request) {
 		for (ParamExpression expression : expressions) {
 			if (!expression.match(request)) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/PatternsRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/PatternsRequestCondition.java
index b81c45f7f3c..5ec810f6ea2 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/PatternsRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/PatternsRequestCondition.java
@@ -196,6 +196,7 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 	 * or {@code null} if no patterns match.
 	 */
 	@Override
+	@Nullable
 	public PatternsRequestCondition getMatchingCondition(HttpServletRequest request) {
 
 		if (this.patterns.isEmpty()) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ProducesRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ProducesRequestCondition.java
index 4203727ebc5..3e6d13b9cde 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ProducesRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/ProducesRequestCondition.java
@@ -185,6 +185,7 @@ public final class ProducesRequestCondition extends AbstractRequestCondition<Pro
 	 * or {@code null} if no expressions match.
 	 */
 	@Override
+	@Nullable
 	public ProducesRequestCondition getMatchingCondition(HttpServletRequest request) {
 		if (CorsUtils.isPreFlightRequest(request)) {
 			return PRE_FLIGHT_MATCH;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestConditionHolder.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestConditionHolder.java
index fe6ee6e22e0..efafd21d4a9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestConditionHolder.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestConditionHolder.java
@@ -110,6 +110,7 @@ public final class RequestConditionHolder extends AbstractRequestCondition<Reque
 	 * holder, return the same holder instance.
 	 */
 	@Override
+	@Nullable
 	public RequestConditionHolder getMatchingCondition(HttpServletRequest request) {
 		if (this.condition == null) {
 			return this;
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java
index ba9e34e43b2..3bf7eb5c517 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java
@@ -98,6 +98,7 @@ public final class RequestMethodsRequestCondition extends AbstractRequestConditi
 	 * request method is OPTIONS.
 	 */
 	@Override
+	@Nullable
 	public RequestMethodsRequestCondition getMatchingCondition(HttpServletRequest request) {
 		if (CorsUtils.isPreFlightRequest(request)) {
 			return matchPreFlight(request);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/AbstractHandlerMethodAdapter.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/AbstractHandlerMethodAdapter.java
index 677e40b0077..3fc9eba11e9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/AbstractHandlerMethodAdapter.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/AbstractHandlerMethodAdapter.java
@@ -80,6 +80,7 @@ public abstract class AbstractHandlerMethodAdapter extends WebContentGenerator i
 	 * This implementation expects the handler to be an {@link HandlerMethod}.
 	 */
 	@Override
+	@Nullable
 	public final ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
 			throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/RequestMappingInfo.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/RequestMappingInfo.java
index 9207ee71d0a..bb842810428 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/RequestMappingInfo.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/RequestMappingInfo.java
@@ -210,6 +210,7 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 	 * @return a new instance in case all conditions match; or {@code null} otherwise
 	 */
 	@Override
+	@Nullable
 	public RequestMappingInfo getMatchingCondition(HttpServletRequest request) {
 		RequestMethodsRequestCondition methods = this.methodsCondition.getMatchingCondition(request);
 		ParamsRequestCondition params = this.paramsCondition.getMatchingCondition(request);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMappingJacksonResponseBodyAdvice.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMappingJacksonResponseBodyAdvice.java
index bcd9bdffd76..fc1a2a2f53c 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMappingJacksonResponseBodyAdvice.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMappingJacksonResponseBodyAdvice.java
@@ -42,6 +42,7 @@ public abstract class AbstractMappingJacksonResponseBodyAdvice implements Respon
 	}
 
 	@Override
+	@Nullable
 	public final Object beforeBodyWrite(@Nullable Object body, MethodParameter returnType,
 			MediaType contentType, Class<? extends HttpMessageConverter<?>> converterType,
 			ServerHttpRequest request, ServerHttpResponse response) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java
index b3c0f1482e1..6afef13aa3c 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java
@@ -122,6 +122,7 @@ public class HttpEntityMethodProcessor extends AbstractMessageConverterMethodPro
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory)
 			throws IOException, HttpMediaTypeNotSupportedException {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMapMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMapMethodArgumentResolver.java
index 0a1f127050a..0db14533dc4 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMapMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMapMethodArgumentResolver.java
@@ -60,6 +60,7 @@ public class MatrixVariableMapMethodArgumentResolver implements HandlerMethodArg
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest request, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMethodArgumentResolver.java
index 6631106fae8..bf1c860a6c1 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/MatrixVariableMethodArgumentResolver.java
@@ -21,6 +21,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.MultiValueMap;
@@ -71,6 +72,7 @@ public class MatrixVariableMethodArgumentResolver extends AbstractNamedValueMeth
 
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
 		Map<String, MultiValueMap<String, String>> pathParameters = (Map<String, MultiValueMap<String, String>>)
 				request.getAttribute(HandlerMapping.MATRIX_VARIABLES_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/PathVariableMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/PathVariableMethodArgumentResolver.java
index 0ad149cbe6d..895cc10aac4 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/PathVariableMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/PathVariableMethodArgumentResolver.java
@@ -89,6 +89,7 @@ public class PathVariableMethodArgumentResolver extends AbstractNamedValueMethod
 
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
 		Map<String, String> uriTemplateVars = (Map<String, String>) request.getAttribute(
 				HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestAttributeMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestAttributeMethodArgumentResolver.java
index a14db8b95b9..92e02d0ba4d 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestAttributeMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestAttributeMethodArgumentResolver.java
@@ -19,6 +19,7 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import javax.servlet.ServletException;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.bind.ServletRequestBindingException;
 import org.springframework.web.bind.annotation.RequestAttribute;
@@ -48,6 +49,7 @@ public class RequestAttributeMethodArgumentResolver extends AbstractNamedValueMe
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request){
 		return request.getAttribute(name, RequestAttributes.SCOPE_REQUEST);
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java
index 3386ccfc939..565ddeca4e9 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java
@@ -187,6 +187,7 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	 * @see #getCustomTypeCondition(Class)
 	 */
 	@Override
+	@Nullable
 	protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
 		RequestMappingInfo info = createRequestMappingInfo(method);
 		if (info != null) {
@@ -205,6 +206,7 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	 * @see #getCustomTypeCondition(Class)
 	 * @see #getCustomMethodCondition(Method)
 	 */
+	@Nullable
 	private RequestMappingInfo createRequestMappingInfo(AnnotatedElement element) {
 		RequestMapping requestMapping = AnnotatedElementUtils.findMergedAnnotation(element, RequestMapping.class);
 		RequestCondition<?> condition = (element instanceof Class ?
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java
index ee5162bce1a..8c826310d73 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java
@@ -108,6 +108,7 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 	}
 
 	@Override
+	@Nullable
 	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest request, @Nullable WebDataBinderFactory binderFactory) throws Exception {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyAdviceChain.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyAdviceChain.java
index 2f1f4966064..8958484c52f 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyAdviceChain.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyAdviceChain.java
@@ -104,6 +104,7 @@ class RequestResponseBodyAdviceChain implements RequestBodyAdvice, ResponseBodyA
 	}
 
 	@Override
+	@Nullable
 	public Object beforeBodyWrite(@Nullable Object body, MethodParameter returnType, MediaType contentType,
 			Class<? extends HttpMessageConverter<?>> converterType,
 			ServerHttpRequest request, ServerHttpResponse response) {
@@ -112,6 +113,7 @@ class RequestResponseBodyAdviceChain implements RequestBodyAdvice, ResponseBodyA
 	}
 
 	@Override
+	@Nullable
 	public Object handleEmptyBody(@Nullable Object body, HttpInputMessage inputMessage, MethodParameter parameter,
 			Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ServletCookieValueMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ServletCookieValueMethodArgumentResolver.java
index 4632325b927..25b3de091a8 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ServletCookieValueMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ServletCookieValueMethodArgumentResolver.java
@@ -51,6 +51,7 @@ public class ServletCookieValueMethodArgumentResolver extends AbstractCookieValu
 
 
 	@Override
+	@Nullable
 	protected Object resolveName(String cookieName, MethodParameter parameter, NativeWebRequest webRequest) throws Exception {
 		HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
 		Assert.state(servletRequest != null, "No HttpServletRequest");
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SessionAttributeMethodArgumentResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SessionAttributeMethodArgumentResolver.java
index efc5ef61a0b..471c96ca604 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SessionAttributeMethodArgumentResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/SessionAttributeMethodArgumentResolver.java
@@ -19,6 +19,7 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import javax.servlet.ServletException;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.bind.ServletRequestBindingException;
 import org.springframework.web.bind.annotation.SessionAttribute;
@@ -48,6 +49,7 @@ public class SessionAttributeMethodArgumentResolver extends AbstractNamedValueMe
 	}
 
 	@Override
+	@Nullable
 	protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request){
 		return request.getAttribute(name, RequestAttributes.SCOPE_SESSION);
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java
index 807d08e5f32..1954b7965e8 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java
@@ -101,6 +101,7 @@ public class DefaultHandlerExceptionResolver extends AbstractHandlerExceptionRes
 
 
 	@Override
+	@Nullable
 	protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,
 			@Nullable Object handler, Exception ex) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractResourceResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractResourceResolver.java
index ef999bab2c4..16781661209 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractResourceResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractResourceResolver.java
@@ -38,6 +38,7 @@ public abstract class AbstractResourceResolver implements ResourceResolver {
 
 
 	@Override
+	@Nullable
 	public Resource resolveResource(@Nullable HttpServletRequest request, String requestPath,
 			List<? extends Resource> locations, ResourceResolverChain chain) {
 
@@ -48,6 +49,7 @@ public abstract class AbstractResourceResolver implements ResourceResolver {
 	}
 
 	@Override
+	@Nullable
 	public String resolveUrlPath(String resourceUrlPath, List<? extends Resource> locations,
 			ResourceResolverChain chain) {
 
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractVersionStrategy.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractVersionStrategy.java
index 9848f9c79e9..eda8d17b5e2 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractVersionStrategy.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/AbstractVersionStrategy.java
@@ -22,6 +22,7 @@ import java.util.regex.Pattern;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -60,6 +61,7 @@ public abstract class AbstractVersionStrategy implements VersionStrategy {
 
 
 	@Override
+	@Nullable
 	public String extractVersion(String requestPath) {
 		return this.pathStrategy.extractVersion(requestPath);
 	}
@@ -89,6 +91,7 @@ public abstract class AbstractVersionStrategy implements VersionStrategy {
 		}
 
 		@Override
+		@Nullable
 		public String extractVersion(String requestPath) {
 			return (requestPath.startsWith(this.prefix) ? this.prefix : null);
 		}
@@ -120,6 +123,7 @@ public abstract class AbstractVersionStrategy implements VersionStrategy {
 		private static final Pattern pattern = Pattern.compile("-(\\S*)\\.");
 
 		@Override
+		@Nullable
 		public String extractVersion(String requestPath) {
 			Matcher matcher = pattern.matcher(requestPath);
 			if (matcher.find()) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/DefaultResourceResolverChain.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/DefaultResourceResolverChain.java
index eb42ebd5ea4..7019a3c976e 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/DefaultResourceResolverChain.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/DefaultResourceResolverChain.java
@@ -48,6 +48,7 @@ class DefaultResourceResolverChain implements ResourceResolverChain {
 
 
 	@Override
+	@Nullable
 	public Resource resolveResource(
 			@Nullable HttpServletRequest request, String requestPath, List<? extends Resource> locations) {
 
@@ -65,6 +66,7 @@ class DefaultResourceResolverChain implements ResourceResolverChain {
 	}
 
 	@Override
+	@Nullable
 	public String resolveUrlPath(String resourcePath, List<? extends Resource> locations) {
 		ResourceResolver resolver = getNext();
 		if (resolver == null) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/GzipResourceResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/GzipResourceResolver.java
index cd618cc3d77..0f9f9acedb1 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/GzipResourceResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/GzipResourceResolver.java
@@ -89,18 +89,22 @@ public class GzipResourceResolver extends AbstractResourceResolver {
 			this.gzipped = original.createRelative(original.getFilename() + ".gz");
 		}
 
+		@Override
 		public InputStream getInputStream() throws IOException {
 			return this.gzipped.getInputStream();
 		}
 
+		@Override
 		public boolean exists() {
 			return this.gzipped.exists();
 		}
 
+		@Override
 		public boolean isReadable() {
 			return this.gzipped.isReadable();
 		}
 
+		@Override
 		public boolean isOpen() {
 			return this.gzipped.isOpen();
 		}
@@ -110,34 +114,43 @@ public class GzipResourceResolver extends AbstractResourceResolver {
 			return this.gzipped.isFile();
 		}
 
+		@Override
 		public URL getURL() throws IOException {
 			return this.gzipped.getURL();
 		}
 
+		@Override
 		public URI getURI() throws IOException {
 			return this.gzipped.getURI();
 		}
 
+		@Override
 		public File getFile() throws IOException {
 			return this.gzipped.getFile();
 		}
 
+		@Override
 		public long contentLength() throws IOException {
 			return this.gzipped.contentLength();
 		}
 
+		@Override
 		public long lastModified() throws IOException {
 			return this.gzipped.lastModified();
 		}
 
+		@Override
 		public Resource createRelative(String relativePath) throws IOException {
 			return this.gzipped.createRelative(relativePath);
 		}
 
+		@Override
+		@Nullable
 		public String getFilename() {
 			return this.original.getFilename();
 		}
 
+		@Override
 		public String getDescription() {
 			return this.gzipped.getDescription();
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java
index c4ba23da701..a705f57fa0a 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java
@@ -244,6 +244,7 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	 * Return the specified CORS configuration.
 	 */
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 		return this.corsConfiguration;
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
index 53818b3ea56..b0c003dc945 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/VersionResourceResolver.java
@@ -295,6 +295,7 @@ public class VersionResourceResolver extends AbstractResourceResolver {
 		}
 
 		@Override
+		@Nullable
 		public String getFilename() {
 			return this.original.getFilename();
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractFlashMapManager.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractFlashMapManager.java
index 4cfaacedb4c..1bf5419c066 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractFlashMapManager.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractFlashMapManager.java
@@ -88,6 +88,7 @@ public abstract class AbstractFlashMapManager implements FlashMapManager {
 
 
 	@Override
+	@Nullable
 	public final FlashMap retrieveAndUpdate(HttpServletRequest request, HttpServletResponse response) {
 		List<FlashMap> allFlashMaps = retrieveFlashMaps(request);
 		if (CollectionUtils.isEmpty(allFlashMaps)) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/SessionFlashMapManager.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/SessionFlashMapManager.java
index e993cde0a0a..2c1ba5faa7a 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/support/SessionFlashMapManager.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/support/SessionFlashMapManager.java
@@ -21,6 +21,7 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 
+import org.springframework.lang.Nullable;
 import org.springframework.web.servlet.FlashMap;
 import org.springframework.web.util.WebUtils;
 
@@ -41,6 +42,7 @@ public class SessionFlashMapManager extends AbstractFlashMapManager {
 	 */
 	@Override
 	@SuppressWarnings("unchecked")
+	@Nullable
 	protected List<FlashMap> retrieveFlashMaps(HttpServletRequest request) {
 		HttpSession session = request.getSession(false);
 		return (session != null ? (List<FlashMap>) session.getAttribute(FLASH_MAPS_SESSION_ATTRIBUTE) : null);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/BindTag.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/BindTag.java
index 310dede393d..91f81a845e5 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/BindTag.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/BindTag.java
@@ -184,6 +184,7 @@ public class BindTag extends HtmlEscapingAwareTag implements EditorAwareTag {
 	}
 
 	@Override
+	@Nullable
 	public final PropertyEditor getEditor() {
 		return getStatus().getEditor();
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/EvalTag.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/EvalTag.java
index b1abd2db503..c9fe065aa2a 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/EvalTag.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/EvalTag.java
@@ -168,6 +168,7 @@ public class EvalTag extends HtmlEscapingAwareTag {
 		}
 
 		@Override
+		@Nullable
 		public Class<?>[] getSpecificTargetClasses() {
 			return null;
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/AbstractDataBoundFormElementTag.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/AbstractDataBoundFormElementTag.java
index 2e3ef8228be..1cce7c6e6e8 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/AbstractDataBoundFormElementTag.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/AbstractDataBoundFormElementTag.java
@@ -198,6 +198,7 @@ public abstract class AbstractDataBoundFormElementTag extends AbstractFormTag im
 	 * Get the bound value.
 	 * @see #getBindStatus()
 	 */
+	@Nullable
 	protected final Object getBoundValue() throws JspException {
 		return getBindStatus().getValue();
 	}
@@ -215,6 +216,7 @@ public abstract class AbstractDataBoundFormElementTag extends AbstractFormTag im
 	 * <p>Use {@link #getPropertyEditor()} for internal rendering purposes.
 	 */
 	@Override
+	@Nullable
 	public final PropertyEditor getEditor() throws JspException {
 		return getPropertyEditor();
 	}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/AbstractCachingViewResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/AbstractCachingViewResolver.java
index 207ce470908..742ed7b3a7a 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/AbstractCachingViewResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/AbstractCachingViewResolver.java
@@ -50,6 +50,7 @@ public abstract class AbstractCachingViewResolver extends WebApplicationObjectSu
 	/** Dummy marker object for unresolved views in the cache Maps */
 	private static final View UNRESOLVED_VIEW = new View() {
 		@Override
+		@Nullable
 		public String getContentType() {
 			return null;
 		}
@@ -143,6 +144,7 @@ public abstract class AbstractCachingViewResolver extends WebApplicationObjectSu
 
 
 	@Override
+	@Nullable
 	public View resolveViewName(String viewName, Locale locale) throws Exception {
 		if (!isCache()) {
 			return createView(viewName, locale);
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/BeanNameViewResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/BeanNameViewResolver.java
index 10396f96197..13312ff5327 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/BeanNameViewResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/BeanNameViewResolver.java
@@ -21,6 +21,7 @@ import java.util.Locale;
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 import org.springframework.web.context.support.WebApplicationObjectSupport;
 import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.ViewResolver;
@@ -67,6 +68,7 @@ public class BeanNameViewResolver extends WebApplicationObjectSupport implements
 
 
 	@Override
+	@Nullable
 	public View resolveViewName(String viewName, Locale locale) throws BeansException {
 		ApplicationContext context = obtainApplicationContext();
 		if (!context.containsBean(viewName)) {
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolver.java
index d3c8b6d5bd9..2c555203cca 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolver.java
@@ -219,6 +219,7 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
 
 
 	@Override
+	@Nullable
 	public View resolveViewName(String viewName, Locale locale) throws Exception {
 		RequestAttributes attrs = RequestContextHolder.getRequestAttributes();
 		Assert.state(attrs instanceof ServletRequestAttributes, "No current ServletRequestAttributes");
@@ -364,6 +365,7 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
 	private static final View NOT_ACCEPTABLE_VIEW = new View() {
 
 		@Override
+		@Nullable
 		public String getContentType() {
 			return null;
 		}
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ViewResolverComposite.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ViewResolverComposite.java
index 6f82fc5bdca..d782578dda5 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ViewResolverComposite.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/view/ViewResolverComposite.java
@@ -27,6 +27,7 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.Ordered;
+import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
 import org.springframework.web.context.ServletContextAware;
 import org.springframework.web.servlet.View;
@@ -101,6 +102,7 @@ public class ViewResolverComposite implements ViewResolver, Ordered, Initializin
 	}
 
 	@Override
+	@Nullable
 	public View resolveViewName(String viewName, Locale locale) throws Exception {
 		for (ViewResolver viewResolver : this.viewResolvers) {
 			View view = viewResolver.resolveViewName(viewName, locale);
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketHttpHeaders.java b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketHttpHeaders.java
index 43fbd601ce9..a28af6d97c1 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketHttpHeaders.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketHttpHeaders.java
@@ -206,6 +206,7 @@ public class WebSocketHttpHeaders extends HttpHeaders {
 	 * @return the first header value; or {@code null}
 	 */
 	@Override
+	@Nullable
 	public String getFirst(String headerName) {
 		return this.headers.getFirst(headerName);
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketSession.java
index b860602c390..9016c3e8300 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/WebSocketSession.java
@@ -43,7 +43,6 @@ public interface WebSocketSession extends Closeable {
 
 	/**
 	 * Return the URI used to open the WebSocket connection.
-	 * ({@code null} on the client side).
 	 */
 	@Nullable
 	URI getUri();
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/AbstractWebSocketSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/AbstractWebSocketSession.java
index b5fa19b6f67..a57c247a7e0 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/AbstractWebSocketSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/AbstractWebSocketSession.java
@@ -74,6 +74,7 @@ public abstract class AbstractWebSocketSession<T> implements NativeWebSocketSess
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <R> R getNativeSession(@Nullable Class<R> requiredType) {
 		return (requiredType == null || requiredType.isInstance(this.nativeSession) ? (R) this.nativeSession : null);
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/NativeWebSocketSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/NativeWebSocketSession.java
index c8c217121f5..87e4431a50b 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/NativeWebSocketSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/NativeWebSocketSession.java
@@ -40,6 +40,6 @@ public interface NativeWebSocketSession extends WebSocketSession {
 	 * or {@code null} if not available
 	 */
 	@Nullable
-	<T> T getNativeSession(Class<T> requiredType);
+	<T> T getNativeSession(@Nullable Class<T> requiredType);
 
 }
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/jetty/JettyWebSocketSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/jetty/JettyWebSocketSession.java
index 61348da16eb..7142c12dd13 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/jetty/JettyWebSocketSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/jetty/JettyWebSocketSession.java
@@ -102,6 +102,7 @@ public class JettyWebSocketSession extends AbstractWebSocketSession<Session> {
 	}
 
 	@Override
+	@Nullable
 	public URI getUri() {
 		checkNativeSessionInitialized();
 		return this.uri;
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/StandardWebSocketSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/StandardWebSocketSession.java
index fd0c8123266..77d1a6d4055 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/StandardWebSocketSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/StandardWebSocketSession.java
@@ -117,6 +117,7 @@ public class StandardWebSocketSession extends AbstractWebSocketSession<Session>
 	}
 
 	@Override
+	@Nullable
 	public URI getUri() {
 		checkNativeSessionInitialized();
 		return this.uri;
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/config/HandlersBeanDefinitionParser.java b/spring-websocket/src/main/java/org/springframework/web/socket/config/HandlersBeanDefinitionParser.java
index 346e48046d4..05a67eb81a9 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/config/HandlersBeanDefinitionParser.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/config/HandlersBeanDefinitionParser.java
@@ -31,6 +31,7 @@ import org.springframework.beans.factory.support.ManagedMap;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 import org.springframework.util.xml.DomUtils;
 import org.springframework.web.socket.server.support.OriginHandshakeInterceptor;
@@ -56,6 +57,7 @@ class HandlersBeanDefinitionParser implements BeanDefinitionParser {
 
 
 	@Override
+	@Nullable
 	public BeanDefinition parse(Element element, ParserContext context) {
 		Object source = context.extractSource(element);
 		CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(), source);
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java b/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
index 0019489847e..9cb8d5134d6 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/config/annotation/WebSocketConfigurationSupport.java
@@ -103,6 +103,7 @@ public class WebSocketConfigurationSupport {
 	private static class NoOpScheduler implements TaskScheduler {
 
 		@Override
+		@Nullable
 		public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
 			throw new IllegalStateException("Unexpected use of scheduler.");
 		}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketSessionDecorator.java b/spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketSessionDecorator.java
index 9bf3b685c9d..f693b820e01 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketSessionDecorator.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/handler/WebSocketSessionDecorator.java
@@ -24,6 +24,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.springframework.http.HttpHeaders;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.socket.CloseStatus;
 import org.springframework.web.socket.WebSocketExtension;
@@ -79,6 +80,7 @@ public class WebSocketSessionDecorator implements WebSocketSession {
 	}
 
 	@Override
+	@Nullable
 	public URI getUri() {
 		return this.delegate.getUri();
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/DefaultSimpUserRegistry.java b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/DefaultSimpUserRegistry.java
index 6ab92cbc0ae..50c47b63fa4 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/DefaultSimpUserRegistry.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/DefaultSimpUserRegistry.java
@@ -143,6 +143,7 @@ public class DefaultSimpUserRegistry implements SimpUserRegistry, SmartApplicati
 	// SimpUserRegistry methods
 
 	@Override
+	@Nullable
 	public SimpUser getUser(String userName) {
 		return this.users.get(userName);
 	}
@@ -198,6 +199,7 @@ public class DefaultSimpUserRegistry implements SimpUserRegistry, SmartApplicati
 		}
 
 		@Override
+		@Nullable
 		public SimpSession getSession(@Nullable String sessionId) {
 			return (sessionId != null ? this.userSessions.get(sessionId) : null);
 		}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolErrorHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolErrorHandler.java
index a2ec6724dcb..68201480d1f 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolErrorHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolErrorHandler.java
@@ -57,6 +57,7 @@ public class StompSubProtocolErrorHandler implements SubProtocolErrorHandler<byt
 	}
 
 	@Override
+	@Nullable
 	public Message<byte[]> handleErrorMessageToClient(Message<byte[]> errorMessage) {
 		StompHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(errorMessage, StompHeaderAccessor.class);
 		Assert.notNull(accessor, "No StompHeaderAccessor");
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java
index 88dd47bda70..98b16102324 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java
@@ -583,6 +583,7 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 	}
 
 	@Override
+	@Nullable
 	public String resolveSessionId(Message<?> message) {
 		return SimpMessageHeaderAccessor.getSessionId(message.getHeaders());
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketAnnotationMethodMessageHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketAnnotationMethodMessageHandler.java
index ce590be4891..3f4ae0bda78 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketAnnotationMethodMessageHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/messaging/WebSocketAnnotationMethodMessageHandler.java
@@ -103,6 +103,7 @@ public class WebSocketAnnotationMethodMessageHandler extends SimpAnnotationMetho
 		}
 
 		@Override
+		@Nullable
 		public Class<?> getBeanType() {
 			return this.adviceBean.getBeanType();
 		}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/ServletServerContainerFactoryBean.java b/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/ServletServerContainerFactoryBean.java
index 5efff0f8bd4..25fcf704317 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/ServletServerContainerFactoryBean.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/ServletServerContainerFactoryBean.java
@@ -133,6 +133,7 @@ public class ServletServerContainerFactoryBean
 
 
 	@Override
+	@Nullable
 	public ServerContainer getObject() {
 		return this.serverContainer;
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/WebSocketClientSockJsSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/WebSocketClientSockJsSession.java
index 1a4a34b9f3e..5419af29c0e 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/WebSocketClientSockJsSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/WebSocketClientSockJsSession.java
@@ -58,6 +58,7 @@ public class WebSocketClientSockJsSession extends AbstractClientSockJsSession im
 
 	@SuppressWarnings("unchecked")
 	@Override
+	@Nullable
 	public <T> T getNativeSession(@Nullable Class<T> requiredType) {
 		return (requiredType == null || requiredType.isInstance(this.webSocketSession) ? (T) this.webSocketSession : null);
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/frame/Jackson2SockJsMessageCodec.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/frame/Jackson2SockJsMessageCodec.java
index 8ed46882c5a..6686fc6f109 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/frame/Jackson2SockJsMessageCodec.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/frame/Jackson2SockJsMessageCodec.java
@@ -25,6 +25,7 @@ import com.fasterxml.jackson.databind.MapperFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -58,11 +59,13 @@ public class Jackson2SockJsMessageCodec extends AbstractSockJsMessageCodec {
 
 
 	@Override
+	@Nullable
 	public String[] decode(String content) throws IOException {
 		return this.objectMapper.readValue(content, String[].class);
 	}
 
 	@Override
+	@Nullable
 	public String[] decodeInputStream(InputStream content) throws IOException {
 		return this.objectMapper.readValue(content, String[].class);
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/AbstractSockJsService.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/AbstractSockJsService.java
index 273bbacd6af..79e773be697 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/AbstractSockJsService.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/AbstractSockJsService.java
@@ -488,6 +488,7 @@ public abstract class AbstractSockJsService implements SockJsService, CorsConfig
 	}
 
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 		if (!this.suppressCors && CorsUtils.isCorsRequest(request)) {
 			CorsConfiguration config = new CorsConfiguration();
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/SockJsHttpRequestHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/SockJsHttpRequestHandler.java
index 81e0c65a065..403f0dad604 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/SockJsHttpRequestHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/support/SockJsHttpRequestHandler.java
@@ -27,6 +27,7 @@ import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
 import org.springframework.http.server.ServletServerHttpRequest;
 import org.springframework.http.server.ServletServerHttpResponse;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.web.HttpRequestHandler;
 import org.springframework.web.context.ServletContextAware;
@@ -143,6 +144,7 @@ public class SockJsHttpRequestHandler
 	}
 
 	@Override
+	@Nullable
 	public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
 		if (this.sockJsService instanceof CorsConfigurationSource) {
 			return ((CorsConfigurationSource) this.sockJsService).getCorsConfiguration(request);
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/JsonpReceivingTransportHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/JsonpReceivingTransportHandler.java
index fd74f8440b9..f4482aed336 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/JsonpReceivingTransportHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/JsonpReceivingTransportHandler.java
@@ -24,6 +24,7 @@ import org.springframework.http.MediaType;
 import org.springframework.http.converter.FormHttpMessageConverter;
 import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.lang.Nullable;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
 import org.springframework.web.socket.WebSocketHandler;
@@ -62,6 +63,7 @@ public class JsonpReceivingTransportHandler extends AbstractHttpReceivingTranspo
 	}
 
 	@Override
+	@Nullable
 	protected String[] readMessages(ServerHttpRequest request) throws IOException {
 		SockJsMessageCodec messageCodec = getServiceConfig().getMessageCodec();
 		MediaType contentType = request.getHeaders().getContentType();
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrReceivingTransportHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrReceivingTransportHandler.java
index dc40b28b2a8..4af55484149 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrReceivingTransportHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/handler/XhrReceivingTransportHandler.java
@@ -20,6 +20,7 @@ import java.io.IOException;
 
 import org.springframework.http.HttpStatus;
 import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.lang.Nullable;
 import org.springframework.web.socket.sockjs.transport.TransportHandler;
 import org.springframework.web.socket.sockjs.transport.TransportType;
 
@@ -37,6 +38,7 @@ public class XhrReceivingTransportHandler extends AbstractHttpReceivingTransport
 	}
 
 	@Override
+	@Nullable
 	protected String[] readMessages(ServerHttpRequest request) throws IOException {
 		return getServiceConfig().getMessageCodec().decodeInputStream(request.getBody());
 	}
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/WebSocketServerSockJsSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/WebSocketServerSockJsSession.java
index 5b5410e97e3..7d1d46826c9 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/WebSocketServerSockJsSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/WebSocketServerSockJsSession.java
@@ -70,6 +70,7 @@ public class WebSocketServerSockJsSession extends AbstractSockJsSession implemen
 
 
 	@Override
+	@Nullable
 	public URI getUri() {
 		Assert.state(this.webSocketSession != null, "WebSocketSession not yet initialized");
 		return this.webSocketSession.getUri();
@@ -143,7 +144,8 @@ public class WebSocketServerSockJsSession extends AbstractSockJsSession implemen
 	}
 
 	@Override
-	public <T> T getNativeSession(Class<T> requiredType) {
+	@Nullable
+	public <T> T getNativeSession(@Nullable Class<T> requiredType) {
 		return (this.webSocketSession instanceof NativeWebSocketSession ?
 				((NativeWebSocketSession) this.webSocketSession).getNativeSession(requiredType) : null);
 	}