Add nullability annotations to module/spring-boot-validation

See gh-46587

module/spring-boot-validation/src/main/java/org/springframework/boot/validation/autoconfigure/PrimaryDefaultValidatorPostProcessor.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.validation.autoconfigure;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
@@ -24,6 +26,7 @@ import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.util.Assert;
 import org.springframework.validation.Validator;
 import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
 
@@ -46,7 +49,7 @@ class PrimaryDefaultValidatorPostProcessor implements ImportBeanDefinitionRegist
 	 */
 	private static final String VALIDATOR_BEAN_NAME = "defaultValidator";
 
-	private ConfigurableListableBeanFactory beanFactory;
+	private @Nullable ConfigurableListableBeanFactory beanFactory;
 
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
@@ -63,7 +66,7 @@ class PrimaryDefaultValidatorPostProcessor implements ImportBeanDefinitionRegist
 		}
 	}
 
-	private BeanDefinition getAutoConfiguredValidator(BeanDefinitionRegistry registry) {
+	private @Nullable BeanDefinition getAutoConfiguredValidator(BeanDefinitionRegistry registry) {
 		if (registry.containsBeanDefinition(VALIDATOR_BEAN_NAME)) {
 			BeanDefinition definition = registry.getBeanDefinition(VALIDATOR_BEAN_NAME);
 			if (definition.getRole() == BeanDefinition.ROLE_INFRASTRUCTURE
@@ -79,6 +82,7 @@ class PrimaryDefaultValidatorPostProcessor implements ImportBeanDefinitionRegist
 	}
 
 	private boolean hasPrimarySpringValidator() {
+		Assert.state(this.beanFactory != null, "'beanFactory' must not be null");
 		String[] validatorBeans = this.beanFactory.getBeanNamesForType(Validator.class, false, false);
 		for (String validatorBean : validatorBeans) {
 			BeanDefinition definition = this.beanFactory.getBeanDefinition(validatorBean);

module/spring-boot-validation/src/main/java/org/springframework/boot/validation/autoconfigure/ValidatorAdapter.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.validation.autoconfigure;
 
 import jakarta.validation.ValidationException;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.DisposableBean;
@@ -26,6 +27,7 @@ import org.springframework.boot.validation.MessageInterpolatorFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.MessageSource;
+import org.springframework.util.Assert;
 import org.springframework.validation.Errors;
 import org.springframework.validation.SmartValidator;
 import org.springframework.validation.Validator;
@@ -104,7 +106,7 @@ public class ValidatorAdapter implements SmartValidator, ApplicationContextAware
 	 * @param validator an existing validator to use or {@code null}
 	 * @return the validator to use
 	 */
-	public static Validator get(ApplicationContext applicationContext, Validator validator) {
+	public static Validator get(ApplicationContext applicationContext, @Nullable Validator validator) {
 		if (validator != null) {
 			return wrap(validator, false);
 		}
@@ -119,7 +121,7 @@ public class ValidatorAdapter implements SmartValidator, ApplicationContextAware
 		return create(applicationContext);
 	}
 
-	private static Validator getExisting(ApplicationContext applicationContext) {
+	private static @Nullable Validator getExisting(ApplicationContext applicationContext) {
 		try {
 			jakarta.validation.Validator validatorBean = applicationContext.getBean(jakarta.validation.Validator.class);
 			if (validatorBean instanceof Validator validator) {
@@ -156,7 +158,8 @@ public class ValidatorAdapter implements SmartValidator, ApplicationContextAware
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public <T> T unwrap(Class<T> type) {
+	public <T> @Nullable T unwrap(@Nullable Class<T> type) {
+		Assert.state(type != null, "'type' must not be null");
 		if (type.isInstance(this.target)) {
 			return (T) this.target;
 		}

module/spring-boot-validation/src/main/java/org/springframework/boot/validation/autoconfigure/package-info.java

@@ -17,4 +17,7 @@
 /**
  * Auto-configuration for (JSR-303) Validation.
  */
+@NullMarked
 package org.springframework.boot.validation.autoconfigure;
+
+import org.jspecify.annotations.NullMarked;