Perform NullAway build-time checks in more modules

This commit enables null-safety build-time checks in
all remaining modules except spring-test.

See gh-32475

gradle/spring-module.gradle

@@ -117,12 +117,11 @@ tasks.withType(JavaCompile).configureEach {
     options.errorprone {
     	disableAllChecks = true
         option("NullAway:CustomContractAnnotations", "org.springframework.lang.Contract")
-        option("NullAway:AnnotatedPackages", "org.springframework.core,org.springframework.expression," +
-        		"org.springframework.web,org.springframework.jms,org.springframework.messaging,org.springframework.jdbc," +
-        		"org.springframework.r2dbc,org.springframework.orm,org.springframework.beans,org.springframework.aop")
+        option("NullAway:AnnotatedPackages", "org.springframework")
         option("NullAway:UnannotatedSubPackages", "org.springframework.instrument,org.springframework.context.index," +
 				"org.springframework.asm,org.springframework.cglib,org.springframework.objenesis," +
-				"org.springframework.javapoet,org.springframework.aot.nativex.substitution,org.springframework.aot.nativex.feature")
+				"org.springframework.javapoet,org.springframework.aot.nativex.substitution,org.springframework.aot.nativex.feature," +
+				"org.springframework.test,org.springframework.mock")
     }
 }
 tasks.compileJava {

spring-context-support/src/main/java/org/springframework/cache/jcache/interceptor/CacheResultInterceptor.java

@@ -101,7 +101,7 @@ class CacheResultInterceptor extends AbstractKeyCacheInterceptor<CacheResultOper
 	private Cache resolveExceptionCache(CacheOperationInvocationContext<CacheResultOperation> context) {
 		CacheResolver exceptionCacheResolver = context.getOperation().getExceptionCacheResolver();
 		if (exceptionCacheResolver != null) {
-			return extractFrom(context.getOperation().getExceptionCacheResolver().resolveCaches(context));
+			return extractFrom(exceptionCacheResolver.resolveCaches(context));
 		}
 		return null;
 	}

spring-context-support/src/main/java/org/springframework/cache/jcache/interceptor/DefaultJCacheOperationSource.java

@@ -188,6 +188,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 		}
 	}
 
+	@SuppressWarnings("NullAway")
 	protected CacheManager getDefaultCacheManager() {
 		if (getCacheManager() == null) {
 			Assert.state(this.beanFactory != null, "BeanFactory required for default CacheManager resolution");
@@ -207,6 +208,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	}
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected CacheResolver getDefaultCacheResolver() {
 		if (getCacheResolver() == null) {
 			this.cacheResolver = SingletonSupplier.of(new SimpleCacheResolver(getDefaultCacheManager()));
@@ -215,6 +217,7 @@ public class DefaultJCacheOperationSource extends AnnotationJCacheOperationSourc
 	}
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected CacheResolver getDefaultExceptionCacheResolver() {
 		if (getExceptionCacheResolver() == null) {
 			this.exceptionCacheResolver = SingletonSupplier.of(new LazyCacheResolver());

spring-context-support/src/main/java/org/springframework/scheduling/quartz/LocalDataSourceJobStore.java

@@ -90,6 +90,7 @@ public class LocalDataSourceJobStore extends JobStoreCMT {
 
 
 	@Override
+	@SuppressWarnings("NullAway")
 	public void initialize(ClassLoadHelper loadHelper, SchedulerSignaler signaler) throws SchedulerConfigException {
 		// Absolutely needs thread-bound DataSource to initialize.
 		this.dataSource = SchedulerFactoryBean.getConfigTimeDataSource();

spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerAccessor.java

@@ -203,6 +203,7 @@ public abstract class SchedulerAccessor implements ResourceLoaderAware {
 	/**
 	 * Register jobs and triggers (within a transaction, if possible).
 	 */
+	@SuppressWarnings("NullAway")
 	protected void registerJobsAndTriggers() throws SchedulerException {
 		TransactionStatus transactionStatus = null;
 		if (this.transactionManager != null) {

spring-context-support/src/main/java/org/springframework/scheduling/quartz/SchedulerFactoryBean.java

@@ -661,6 +661,7 @@ public class SchedulerFactoryBean extends SchedulerAccessor implements FactoryBe
 	 * @see #afterPropertiesSet
 	 * @see org.quartz.SchedulerFactory#getScheduler
 	 */
+	@SuppressWarnings("NullAway")
 	protected Scheduler createScheduler(SchedulerFactory schedulerFactory, @Nullable String schedulerName)
 			throws SchedulerException {
 

spring-context/src/main/java/org/springframework/context/annotation/BeanMethod.java

@@ -43,6 +43,7 @@ final class BeanMethod extends ConfigurationMethod {
 
 
 	@Override
+	@SuppressWarnings("NullAway")
 	public void validate(ProblemReporter problemReporter) {
 		if ("void".equals(getMetadata().getReturnTypeName())) {
 			// declared as void: potential misuse of @Bean, maybe meant as init method instead?

spring-context/src/main/java/org/springframework/context/annotation/ComponentScanBeanDefinitionParser.java

@@ -40,6 +40,7 @@ import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.core.type.filter.RegexPatternTypeFilter;
 import org.springframework.core.type.filter.TypeFilter;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -112,14 +113,18 @@ public class ComponentScanBeanDefinitionParser implements BeanDefinitionParser {
 			parseBeanNameGenerator(element, scanner);
 		}
 		catch (Exception ex) {
-			parserContext.getReaderContext().error(ex.getMessage(), parserContext.extractSource(element), ex.getCause());
+			String message = ex.getMessage();
+			Assert.state(message != null, "Exception message must not be null");
+			parserContext.getReaderContext().error(message, parserContext.extractSource(element), ex.getCause());
 		}
 
 		try {
 			parseScope(element, scanner);
 		}
 		catch (Exception ex) {
-			parserContext.getReaderContext().error(ex.getMessage(), parserContext.extractSource(element), ex.getCause());
+			String message = ex.getMessage();
+			Assert.state(message != null, "Exception message must not be null");
+			parserContext.getReaderContext().error(message, parserContext.extractSource(element), ex.getCause());
 		}
 
 		parseTypeFilters(element, scanner, parserContext);
@@ -214,8 +219,10 @@ public class ComponentScanBeanDefinitionParser implements BeanDefinitionParser {
 							"Ignoring non-present type filter class: " + ex, parserContext.extractSource(element));
 				}
 				catch (Exception ex) {
+					String message = ex.getMessage();
+					Assert.state(message != null, "Exception message must not be null");
 					parserContext.getReaderContext().error(
-							ex.getMessage(), parserContext.extractSource(element), ex.getCause());
+							message, parserContext.extractSource(element), ex.getCause());
 				}
 			}
 		}

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClass.java

@@ -219,6 +219,7 @@ final class ConfigurationClass {
 		return this.importBeanDefinitionRegistrars;
 	}
 
+	@SuppressWarnings("NullAway")
 	void validate(ProblemReporter problemReporter) {
 		Map<String, Object> attributes = this.metadata.getAnnotationAttributes(Configuration.class.getName());
 

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -819,6 +819,7 @@ class ConfigurationClassParser {
 					deferredImport.getConfigurationClass());
 		}
 
+		@SuppressWarnings("NullAway")
 		void processGroupImports() {
 			for (DeferredImportSelectorGrouping grouping : this.groupings.values()) {
 				Predicate<String> filter = grouping.getCandidateFilter();

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassPostProcessor.java

@@ -325,6 +325,7 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 
 	@Override
 	@Nullable
+	@SuppressWarnings("NullAway")
 	public BeanFactoryInitializationAotContribution processAheadOfTime(ConfigurableListableBeanFactory beanFactory) {
 		boolean hasPropertySourceDescriptors = !CollectionUtils.isEmpty(this.propertySourceDescriptors);
 		boolean hasImportRegistry = beanFactory.containsBean(IMPORT_REGISTRY_BEAN_NAME);
@@ -556,6 +557,7 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 		}
 
 		@Override
+		@Nullable
 		public PropertyValues postProcessProperties(@Nullable PropertyValues pvs, Object bean, String beanName) {
 			// Inject the BeanFactory before AutowiredAnnotationBeanPostProcessor's
 			// postProcessProperties method attempts to autowire other configuration beans.

spring-context/src/main/java/org/springframework/context/annotation/ContextAnnotationAutowireCandidateResolver.java

@@ -98,6 +98,7 @@ public class ContextAnnotationAutowireCandidateResolver extends QualifierAnnotat
 				return descriptor.getDependencyType();
 			}
 			@Override
+			@SuppressWarnings("NullAway")
 			public Object getTarget() {
 				Set<String> autowiredBeanNames = (beanName != null ? new LinkedHashSet<>(1) : null);
 				Object target = dlbf.doResolveDependency(descriptor, beanName, autowiredBeanNames, null);

spring-context/src/main/java/org/springframework/context/annotation/ProfileCondition.java

@@ -31,6 +31,7 @@ import org.springframework.util.MultiValueMap;
 class ProfileCondition implements Condition {
 
 	@Override
+	@SuppressWarnings("NullAway")
 	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
 		MultiValueMap<String, Object> attrs = metadata.getAllAnnotationAttributes(Profile.class.getName());
 		if (attrs != null) {

spring-context/src/main/java/org/springframework/context/event/AbstractApplicationEventMulticaster.java

@@ -40,6 +40,7 @@ import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -229,6 +230,7 @@ public abstract class AbstractApplicationEventMulticaster
 	 * @param retriever the ListenerRetriever, if supposed to populate one (for caching purposes)
 	 * @return the pre-filtered list of application listeners for the given event and source type
 	 */
+	@SuppressWarnings("NullAway")
 	private Collection<ApplicationListener<?>> retrieveApplicationListeners(
 			ResolvableType eventType, @Nullable Class<?> sourceType, @Nullable CachedListenerRetriever retriever) {
 
@@ -313,7 +315,7 @@ public abstract class AbstractApplicationEventMulticaster
 
 		AnnotationAwareOrderComparator.sort(allListeners);
 		if (retriever != null) {
-			if (filteredListenerBeans.isEmpty()) {
+			if (CollectionUtils.isEmpty(filteredListenerBeans)) {
 				retriever.applicationListeners = new LinkedHashSet<>(allListeners);
 				retriever.applicationListenerBeans = filteredListenerBeans;
 			}

spring-context/src/main/java/org/springframework/context/event/ApplicationListenerMethodAdapter.java

@@ -460,6 +460,7 @@ public class ApplicationListenerMethodAdapter implements GenericApplicationListe
 		}
 	}
 
+	@SuppressWarnings("NullAway")
 	private String getInvocationErrorMessage(Object bean, @Nullable String message, @Nullable Object[] resolvedArgs) {
 		StringBuilder sb = new StringBuilder(getDetailedErrorMessage(bean, message));
 		sb.append("Resolved arguments: \n");

spring-context/src/main/java/org/springframework/context/event/EventListenerMethodProcessor.java

@@ -111,7 +111,7 @@ public class EventListenerMethodProcessor
 	@Override
 	public void afterSingletonsInstantiated() {
 		ConfigurableListableBeanFactory beanFactory = this.beanFactory;
-		Assert.state(this.beanFactory != null, "No ConfigurableListableBeanFactory set");
+		Assert.state(beanFactory != null, "No ConfigurableListableBeanFactory set");
 		String[] beanNames = beanFactory.getBeanNamesForType(Object.class);
 		for (String beanName : beanNames) {
 			if (!ScopedProxyUtils.isScopedTarget(beanName)) {

spring-context/src/main/java/org/springframework/context/i18n/LocaleContextThreadLocalAccessor.java

@@ -18,6 +18,8 @@ package org.springframework.context.i18n;
 
 import io.micrometer.context.ThreadLocalAccessor;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Adapt {@link LocaleContextHolder} to the {@link ThreadLocalAccessor} contract
  * to assist the Micrometer Context Propagation library with {@link LocaleContext}
@@ -40,6 +42,7 @@ public class LocaleContextThreadLocalAccessor implements ThreadLocalAccessor<Loc
 	}
 
 	@Override
+	@Nullable
 	public LocaleContext getValue() {
 		return LocaleContextHolder.getLocaleContext();
 	}

spring-context/src/main/java/org/springframework/format/datetime/standard/DateTimeFormatterRegistrar.java

@@ -51,6 +51,7 @@ import org.springframework.format.annotation.DateTimeFormat.ISO;
  * @see org.springframework.format.FormatterRegistrar#registerFormatters
  * @see org.springframework.format.datetime.DateFormatterRegistrar
  */
+@SuppressWarnings("NullAway")
 public class DateTimeFormatterRegistrar implements FormatterRegistrar {
 
 	private enum Type {DATE, TIME, DATE_TIME}

spring-context/src/main/java/org/springframework/jmx/export/MBeanExporter.java

@@ -993,6 +993,7 @@ public class MBeanExporter extends MBeanRegistrationSupport implements MBeanExpo
 	 * Unregister the configured {@link NotificationListener NotificationListeners}
 	 * from the {@link MBeanServer}.
 	 */
+	@SuppressWarnings("NullAway")
 	private void unregisterNotificationListeners() {
 		if (this.server != null) {
 			this.registeredNotificationListeners.forEach((bean, mappedObjectNames) -> {

spring-context/src/main/java/org/springframework/jmx/export/annotation/AnnotationJmxAttributeSource.java

@@ -43,6 +43,7 @@ import org.springframework.core.annotation.RepeatableContainers;
 import org.springframework.jmx.export.metadata.InvalidMetadataException;
 import org.springframework.jmx.export.metadata.JmxAttributeSource;
 import org.springframework.lang.Nullable;
+import org.springframework.util.StringUtils;
 import org.springframework.util.StringValueResolver;
 
 /**
@@ -117,7 +118,7 @@ public class AnnotationJmxAttributeSource implements JmxAttributeSource, BeanFac
 		pvs.removePropertyValue("defaultValue");
 		PropertyAccessorFactory.forBeanPropertyAccess(bean).setPropertyValues(pvs);
 		String defaultValue = (String) map.get("defaultValue");
-		if (!defaultValue.isEmpty()) {
+		if (StringUtils.hasLength(defaultValue)) {
 			bean.setDefaultValue(defaultValue);
 		}
 		return bean;

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -682,7 +682,8 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 		}
 	}
 
-	private void assertValidators(Validator... validators) {
+	@SuppressWarnings("NullAway")
+	private void assertValidators(@Nullable Validator... validators) {
 		Object target = getTarget();
 		for (Validator validator : validators) {
 			if (validator != null && (target != null && !validator.supports(target.getClass()))) {
@@ -741,6 +742,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * {@link #setExcludedValidators(Predicate) exclude predicate}.
 	 * @since 6.1
 	 */
+	@SuppressWarnings("NullAway")
 	public List<Validator> getValidatorsToApply() {
 		return (this.excludedValidators != null ?
 				this.validators.stream().filter(validator -> !this.excludedValidators.test(validator)).toList() :
@@ -1168,6 +1170,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #getBindingErrorProcessor
 	 * @see BindingErrorProcessor#processMissingFieldError
 	 */
+	@SuppressWarnings("NullAway")
 	protected void checkRequiredFields(MutablePropertyValues mpvs) {
 		String[] requiredFields = getRequiredFields();
 		if (!ObjectUtils.isEmpty(requiredFields)) {

spring-context/src/main/java/org/springframework/validation/DefaultMessageCodesResolver.java

@@ -242,7 +242,8 @@ public class DefaultMessageCodesResolver implements MessageCodesResolver, Serial
 		 * {@link DefaultMessageCodesResolver#CODE_SEPARATOR}, skipping zero-length or
 		 * null elements altogether.
 		 */
-		public static String toDelimitedString(String... elements) {
+		@SuppressWarnings("NullAway")
+		public static String toDelimitedString(@Nullable String... elements) {
 			StringJoiner rtn = new StringJoiner(CODE_SEPARATOR);
 			for (String element : elements) {
 				if (StringUtils.hasLength(element)) {

spring-context/src/main/java/org/springframework/validation/FieldError.java

@@ -107,8 +107,7 @@ public class FieldError extends ObjectError {
 		if (!super.equals(other)) {
 			return false;
 		}
-		FieldError otherError = (FieldError) other;
-		return (getField().equals(otherError.getField()) &&
+		return (other instanceof FieldError otherError && getField().equals(otherError.getField()) &&
 				ObjectUtils.nullSafeEquals(getRejectedValue(), otherError.getRejectedValue()) &&
 				isBindingFailure() == otherError.isBindingFailure());
 	}

spring-context/src/main/java/org/springframework/validation/method/ParameterValidationResult.java

@@ -173,8 +173,8 @@ public class ParameterValidationResult {
 		if (!super.equals(other)) {
 			return false;
 		}
-		ParameterValidationResult otherResult = (ParameterValidationResult) other;
-		return (getMethodParameter().equals(otherResult.getMethodParameter()) &&
+		return (other instanceof ParameterValidationResult otherResult &&
+				getMethodParameter().equals(otherResult.getMethodParameter()) &&
 				ObjectUtils.nullSafeEquals(getArgument(), otherResult.getArgument()) &&
 				ObjectUtils.nullSafeEquals(getContainerIndex(), otherResult.getContainerIndex()) &&
 				ObjectUtils.nullSafeEquals(getContainerKey(), otherResult.getContainerKey()));

spring-core/src/main/java/org/springframework/aot/hint/BindingReflectionHintsRegistrar.java

@@ -63,6 +63,7 @@ public class BindingReflectionHintsRegistrar {
 	 * @param hints the hints instance to use
 	 * @param types the types to register
 	 */
+	@SuppressWarnings("NullAway")
 	public void registerReflectionHints(ReflectionHints hints, @Nullable Type... types) {
 		Set<Type> seen = new HashSet<>();
 		for (Type type : types) {

spring-core/src/main/java/org/springframework/core/CoroutinesUtils.java

@@ -108,7 +108,7 @@ public abstract class CoroutinesUtils {
 	 * @throws IllegalArgumentException if {@code method} is not a suspending function
 	 * @since 6.0
 	 */
-	@SuppressWarnings({"deprecation", "DataFlowIssue"})
+	@SuppressWarnings({"deprecation", "DataFlowIssue", "NullAway"})
 	public static Publisher<?> invokeSuspendingFunction(
 			CoroutineContext context, Method method, @Nullable Object target, @Nullable Object... args) {
 

spring-core/src/main/java/org/springframework/util/PlaceholderParser.java

@@ -322,6 +322,7 @@ final class PlaceholderParser {
 		}
 
 		@Override
+		@Nullable
 		public String resolvePlaceholder(String placeholderName) {
 			String value = this.resolver.resolvePlaceholder(placeholderName);
 			if (value != null && logger.isTraceEnabled()) {
@@ -358,6 +359,7 @@ final class PlaceholderParser {
 		}
 
 		public void removePlaceholder(String placeholder) {
+			Assert.state(this.visitedPlaceholders != null, "Visited placeholders must not be null");
 			this.visitedPlaceholders.remove(placeholder);
 		}
 

spring-core/src/main/java/org/springframework/util/StreamUtils.java

@@ -25,6 +25,7 @@ import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.nio.charset.Charset;
 
+import org.springframework.lang.Contract;
 import org.springframework.lang.Nullable;
 
 /**
@@ -201,6 +202,7 @@ public abstract class StreamUtils {
 	 * @throws IOException in case of I/O errors
 	 * @since 4.3
 	 */
+	@Contract("null -> fail")
 	public static int drain(@Nullable InputStream in) throws IOException {
 		Assert.notNull(in, "No InputStream specified");
 		return (int) in.transferTo(OutputStream.nullOutputStream());

spring-jms/src/main/java/org/springframework/jms/connection/JmsResourceHolder.java

@@ -222,6 +222,7 @@ public class JmsResourceHolder extends ResourceHolderSupport {
 	 * for the given connection, or {@code null} if none.
 	 */
 	@Nullable
+	@SuppressWarnings("NullAway")
 	public <S extends Session> S getSession(Class<S> sessionType, @Nullable Connection connection) {
 		Deque<Session> sessions =
 				(connection != null ? this.sessionsPerConnection.get(connection) : this.sessions);

spring-jms/src/main/java/org/springframework/jms/listener/SimpleMessageListenerContainer.java

@@ -344,6 +344,7 @@ public class SimpleMessageListenerContainer extends AbstractMessageListenerConta
 	 * @see #executeListener
 	 * @see #setExposeListenerSession
 	 */
+	@SuppressWarnings("NullAway")
 	protected void processMessage(Message message, Session session) {
 		ConnectionFactory connectionFactory = getConnectionFactory();
 		boolean exposeResource = (connectionFactory != null && isExposeListenerSession());

spring-messaging/src/main/java/org/springframework/messaging/rsocket/service/RSocketServiceMethod.java

@@ -92,6 +92,7 @@ final class RSocketServiceMethod {
 	}
 
 	@Nullable
+	@SuppressWarnings("NullAway")
 	private static String initRoute(
 			Method method, Class<?> containingClass, RSocketStrategies strategies,
 			@Nullable StringValueResolver embeddedValueResolver) {

spring-orm/src/main/java/org/springframework/orm/jpa/persistenceunit/PersistenceManagedTypesBeanRegistrationAotProcessor.java

@@ -203,6 +203,7 @@ class PersistenceManagedTypesBeanRegistrationAotProcessor implements BeanRegistr
 			});
 		}
 
+		@SuppressWarnings("NullAway")
 		private void registerInstantiatorForReflection(ReflectionHints reflection, @Nullable Annotation annotation) {
 			if (annotation == null) {
 				return;

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java

@@ -409,7 +409,9 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 							future.get();
 						}
 						catch (ExecutionException ex) {
-							if (txAttr.rollbackOn(ex.getCause())) {
+							Throwable cause = ex.getCause();
+							Assert.state(cause != null, "Cause must not be null");
+							if (txAttr.rollbackOn(cause)) {
 								status.setRollbackOnly();
 							}
 						}
@@ -901,7 +903,9 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 
 		@Override
 		public String toString() {
-			return getCause().toString();
+			Throwable cause = getCause();
+			Assert.state(cause != null, "Cause must not be null");
+			return cause.toString();
 		}
 	}
 

spring-web/src/main/java/org/springframework/http/InvalidMediaTypeException.java

@@ -16,6 +16,7 @@
 
 package org.springframework.http;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.InvalidMimeTypeException;
 
 /**
@@ -36,8 +37,8 @@ public class InvalidMediaTypeException extends IllegalArgumentException {
 	 * @param mediaType the offending media type
 	 * @param message a detail message indicating the invalid part
 	 */
-	public InvalidMediaTypeException(String mediaType, String message) {
-		super("Invalid media type \"" + mediaType + "\": " + message);
+	public InvalidMediaTypeException(String mediaType, @Nullable String message) {
+		super(message != null ? "Invalid media type \"" + mediaType + "\": " + message : "Invalid media type \"" + mediaType);
 		this.mediaType = mediaType;
 	}
 

spring-web/src/main/java/org/springframework/http/RequestEntity.java

@@ -205,8 +205,8 @@ public class RequestEntity<T> extends HttpEntity<T> {
 		if (!super.equals(other)) {
 			return false;
 		}
-		RequestEntity<?> otherEntity = (RequestEntity<?>) other;
-		return (ObjectUtils.nullSafeEquals(this.method, otherEntity.method) &&
+		return (other instanceof RequestEntity<?> otherEntity &&
+				ObjectUtils.nullSafeEquals(this.method, otherEntity.method) &&
 				ObjectUtils.nullSafeEquals(this.url, otherEntity.url));
 	}
 
@@ -736,8 +736,8 @@ public class RequestEntity<T> extends HttpEntity<T> {
 			if (!super.equals(other)) {
 				return false;
 			}
-			UriTemplateRequestEntity<?> otherEntity = (UriTemplateRequestEntity<?>) other;
-			return (ObjectUtils.nullSafeEquals(this.uriTemplate, otherEntity.uriTemplate) &&
+			return (other instanceof UriTemplateRequestEntity<?> otherEntity &&
+					ObjectUtils.nullSafeEquals(this.uriTemplate, otherEntity.uriTemplate) &&
 					ObjectUtils.nullSafeEquals(this.uriVarsArray, otherEntity.uriVarsArray) &&
 					ObjectUtils.nullSafeEquals(this.uriVarsMap, otherEntity.uriVarsMap));
 		}

spring-web/src/main/java/org/springframework/http/ResponseEntity.java

@@ -162,8 +162,7 @@ public class ResponseEntity<T> extends HttpEntity<T> {
 		if (!super.equals(other)) {
 			return false;
 		}
-		ResponseEntity<?> otherEntity = (ResponseEntity<?>) other;
-		return ObjectUtils.nullSafeEquals(this.status, otherEntity.status);
+		return (other instanceof ResponseEntity<?> otherEntity && ObjectUtils.nullSafeEquals(this.status, otherEntity.status));
 	}
 
 	@Override

spring-web/src/main/java/org/springframework/http/client/AbstractStreamingClientHttpRequest.java

@@ -63,6 +63,7 @@ abstract class AbstractStreamingClientHttpRequest extends AbstractClientHttpRequ
 	}
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected final ClientHttpResponse executeInternal(HttpHeaders headers) throws IOException {
 		if (this.body == null && this.bodyStream != null) {
 			this.body = outputStream -> this.bodyStream.writeTo(outputStream);

spring-web/src/main/java/org/springframework/http/client/JdkClientHttpRequest.java

@@ -90,6 +90,7 @@ class JdkClientHttpRequest extends AbstractStreamingClientHttpRequest {
 
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected ClientHttpResponse executeInternal(HttpHeaders headers, @Nullable Body body) throws IOException {
 		try {
 			HttpRequest request = buildRequest(headers, body);

spring-web/src/main/java/org/springframework/http/client/JettyClientHttpRequest.java

@@ -69,6 +69,7 @@ class JettyClientHttpRequest extends AbstractStreamingClientHttpRequest {
 	}
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected ClientHttpResponse executeInternal(HttpHeaders headers, @Nullable Body body) throws IOException {
 		if (!headers.isEmpty()) {
 			this.request.headers(httpFields -> {

spring-web/src/main/java/org/springframework/http/codec/ServerSentEventHttpMessageReader.java

@@ -138,6 +138,7 @@ public class ServerSentEventHttpMessageReader implements HttpMessageReader<Objec
 	}
 
 	@Nullable
+	@SuppressWarnings("NullAway")
 	private Object buildEvent(List<String> lines, ResolvableType valueType, boolean shouldWrap,
 			Map<String, Object> hints) {
 

spring-web/src/main/java/org/springframework/http/codec/multipart/MultipartParser.java

@@ -49,6 +49,7 @@ import org.springframework.lang.Nullable;
  * @author Arjen Poutsma
  * @since 5.3
  */
+@SuppressWarnings("NullAway")
 final class MultipartParser extends BaseSubscriber<DataBuffer> {
 
 	private static final byte CR = '\r';
@@ -115,6 +116,7 @@ final class MultipartParser extends BaseSubscriber<DataBuffer> {
 	}
 
 	@Override
+	@SuppressWarnings("NullAway")
 	protected void hookOnNext(DataBuffer value) {
 		this.requestOutstanding.set(false);
 		this.state.get().onNext(value);

spring-web/src/main/java/org/springframework/http/codec/multipart/PartGenerator.java

@@ -57,6 +57,7 @@ import org.springframework.util.FastByteArrayOutputStream;
  * @author Arjen Poutsma
  * @since 5.3
  */
+@SuppressWarnings("NullAway")
 final class PartGenerator extends BaseSubscriber<MultipartParser.Token> {
 
 	private static final Log logger = LogFactory.getLog(PartGenerator.class);

spring-web/src/main/java/org/springframework/http/converter/ResourceRegionHttpMessageConverter.java

@@ -167,6 +167,7 @@ public class ResourceRegionHttpMessageConverter extends AbstractGenericHttpMessa
 		}
 	}
 
+	@SuppressWarnings("NullAway")
 	private void writeResourceRegionCollection(Collection<ResourceRegion> resourceRegions,
 			HttpOutputMessage outputMessage) throws IOException {
 

spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java

@@ -329,7 +329,8 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 		}
 
 		// Do not log warning for serializer not found (note: different message wording on Jackson 2.9)
-		boolean debugLevel = (cause instanceof JsonMappingException && cause.getMessage().startsWith("Cannot find"));
+		boolean debugLevel = (cause instanceof JsonMappingException && cause.getMessage() != null &&
+				cause.getMessage().startsWith("Cannot find"));
 
 		if (debugLevel ? logger.isDebugEnabled() : logger.isWarnEnabled()) {
 			String msg = "Failed to evaluate Jackson " + (type instanceof JavaType ? "de" : "") +

spring-web/src/main/java/org/springframework/http/server/reactive/AbstractListenerReadPublisher.java

@@ -47,6 +47,7 @@ import org.springframework.util.Assert;
  * @since 5.0
  * @param <T> the type of element signaled
  */
+@SuppressWarnings("NullAway")
 public abstract class AbstractListenerReadPublisher<T> implements Publisher<T> {
 
 	/**

spring-web/src/main/java/org/springframework/http/server/reactive/AbstractListenerWriteFlushProcessor.java

@@ -40,6 +40,7 @@ import org.springframework.util.Assert;
  * @since 5.0
  * @param <T> the type of element signaled to the {@link Subscriber}
  */
+@SuppressWarnings("NullAway")
 public abstract class AbstractListenerWriteFlushProcessor<T> implements Processor<Publisher<? extends T>, Void> {
 
 	/**

spring-web/src/main/java/org/springframework/http/server/reactive/AbstractListenerWriteProcessor.java

@@ -43,6 +43,7 @@ import org.springframework.util.StringUtils;
  * @since 5.0
  * @param <T> the type of element signaled to the {@link Subscriber}
  */
+@SuppressWarnings("NullAway")
 public abstract class AbstractListenerWriteProcessor<T> implements Processor<T, Void> {
 
 	/**

spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java

@@ -131,6 +131,7 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 		return new URI(url.toString());
 	}
 
+	@SuppressWarnings("NullAway")
 	private static MultiValueMap<String, String> initHeaders(
 			MultiValueMap<String, String> headerValues, HttpServletRequest request) {
 

spring-web/src/main/java/org/springframework/http/server/reactive/WriteResultPublisher.java

@@ -36,6 +36,7 @@ import org.springframework.util.Assert;
  * @author Rossen Stoyanchev
  * @since 5.0
  */
+@SuppressWarnings("NullAway")
 class WriteResultPublisher implements Publisher<Void> {
 
 	/**

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceMethod.java

@@ -489,7 +489,9 @@ final class HttpServiceMethod {
 
 			return request -> client.exchangeForEntityFlux(request, bodyType)
 					.map(entity -> {
-						Object body = reactiveAdapter.fromPublisher(entity.getBody());
+						Flux<?> entityBody = entity.getBody();
+						Assert.state(entityBody != null, "Entity body must not be null");
+						Object body = reactiveAdapter.fromPublisher(entityBody);
 						return new ResponseEntity<>(body, entity.getHeaders(), entity.getStatusCode());
 					});
 		}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMapping.java

@@ -177,6 +177,7 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 					if (this.embeddedValueResolver != null) {
 						prefix = this.embeddedValueResolver.resolveStringValue(prefix);
 					}
+					Assert.state(prefix != null, "Prefix must not be null");
 					info = RequestMappingInfo.paths(prefix).options(this.config).build().combine(info);
 					break;
 				}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodArgumentResolver.java

@@ -141,7 +141,7 @@ public abstract class AbstractMessageConverterMethodArgumentResolver implements
 	 * @throws HttpMediaTypeNotSupportedException if no suitable message converter is found
 	 */
 	@Nullable
-	@SuppressWarnings({"rawtypes", "unchecked"})
+	@SuppressWarnings({"rawtypes", "unchecked", "NullAway"})
 	protected <T> Object readWithMessageConverters(HttpInputMessage inputMessage, MethodParameter parameter,
 			Type targetType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {
 

spring-webmvc/src/main/java/org/springframework/web/servlet/tags/MessageTag.java

@@ -306,6 +306,7 @@ public class MessageTag extends HtmlEscapingAwareTag implements ArgumentAware {
 	 * Resolve the specified message into a concrete message String.
 	 * The returned message String should be unescaped.
 	 */
+	@SuppressWarnings("NullAway")
 	protected String resolveMessage() throws JspException, NoSuchMessageException {
 		MessageSource messageSource = getMessageSource();