Add support for JPA 4.0 @PersistenceAgent injection

Closes gh-36264

Author: jhoeller

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

@@ -152,12 +152,12 @@ public class CommonAnnotationBeanPostProcessor extends InitDestroyAnnotationBean
 	private static final Set<Class<? extends Annotation>> resourceAnnotationTypes = CollectionUtils.newLinkedHashSet(2);
 
 	static {
-		JAKARTA_RESOURCE_TYPE = loadAnnotationType("jakarta.annotation.Resource");
+		JAKARTA_RESOURCE_TYPE = AnnotationUtils.loadAnnotationType("jakarta.annotation.Resource");
 		if (JAKARTA_RESOURCE_TYPE != null) {
 			resourceAnnotationTypes.add(JAKARTA_RESOURCE_TYPE);
 		}
 
-		EJB_ANNOTATION_TYPE = loadAnnotationType("jakarta.ejb.EJB");
+		EJB_ANNOTATION_TYPE = AnnotationUtils.loadAnnotationType("jakarta.ejb.EJB");
 		if (EJB_ANNOTATION_TYPE != null) {
 			resourceAnnotationTypes.add(EJB_ANNOTATION_TYPE);
 		}
@@ -191,8 +191,8 @@ public CommonAnnotationBeanPostProcessor() {
 		setOrder(Ordered.LOWEST_PRECEDENCE - 3);
 
 		// Jakarta EE 9 set of annotations in jakarta.annotation package
-		addInitAnnotationType(loadAnnotationType("jakarta.annotation.PostConstruct"));
-		addDestroyAnnotationType(loadAnnotationType("jakarta.annotation.PreDestroy"));
+		addInitAnnotationType(AnnotationUtils.loadAnnotationType("jakarta.annotation.PostConstruct"));
+		addDestroyAnnotationType(AnnotationUtils.loadAnnotationType("jakarta.annotation.PreDestroy"));
 
 		// java.naming module present on JDK 9+?
 		if (JNDI_PRESENT) {
@@ -575,18 +575,6 @@ protected Object autowireResource(BeanFactory factory, LookupElement element, @N
 	}
 
 
-	@SuppressWarnings("unchecked")
-	private static @Nullable Class<? extends Annotation> loadAnnotationType(String name) {
-		try {
-			return (Class<? extends Annotation>)
-					ClassUtils.forName(name, CommonAnnotationBeanPostProcessor.class.getClassLoader());
-		}
-		catch (ClassNotFoundException ex) {
-			return null;
-		}
-	}
-
-
 	/**
 	 * Class representing generic injection information about an annotated field
 	 * or setter method, supporting @Resource and related annotations.
@@ -783,16 +771,13 @@ public void applyTo(GenerationContext generationContext, BeanRegistrationCode be
 					});
 			GeneratedMethod generateMethod = generatedClass.getMethods().add("apply", method -> {
 				method.addJavadoc("Apply resource autowiring.");
-				method.addModifiers(javax.lang.model.element.Modifier.PUBLIC,
-						javax.lang.model.element.Modifier.STATIC);
+				method.addModifiers(javax.lang.model.element.Modifier.PUBLIC, javax.lang.model.element.Modifier.STATIC);
 				method.addParameter(RegisteredBean.class, REGISTERED_BEAN_PARAMETER);
 				method.addParameter(this.target, INSTANCE_PARAMETER);
 				method.returns(this.target);
-				method.addCode(generateMethodCode(generatedClass.getName(),
-						generationContext.getRuntimeHints()));
+				method.addCode(generateMethodCode(generatedClass.getName(), generationContext.getRuntimeHints()));
 			});
 			beanRegistrationCode.addInstancePostProcessor(generateMethod.toMethodReference());
-
 			registerHints(generationContext.getRuntimeHints());
 		}
 

spring-core/src/main/java/org/springframework/core/annotation/AnnotationUtils.java

@@ -36,6 +36,7 @@
 import org.springframework.core.annotation.AnnotationTypeMapping.MirrorSets.MirrorSet;
 import org.springframework.core.annotation.MergedAnnotation.Adapt;
 import org.springframework.core.annotation.MergedAnnotations.SearchStrategy;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.ReflectionUtils;
@@ -177,6 +178,23 @@ public static boolean isCandidateClass(Class<?> clazz, String annotationName) {
 		return true;
 	}
 
+	/**
+	 * Load the specified annotation type, if available.
+	 * @param annotationName the fully-qualified name of the annotation type
+	 * @return the annotation type as a {@code Class}, or {@code null} if not found
+	 * @since 7.1
+	 */
+	@SuppressWarnings("unchecked")
+	public static @Nullable Class<? extends Annotation> loadAnnotationType(String annotationName) {
+		try {
+			return (Class<? extends Annotation>)
+					ClassUtils.forName(annotationName, AnnotationUtils.class.getClassLoader());
+		}
+		catch (ClassNotFoundException ex) {
+			return null;
+		}
+	}
+
 	/**
 	 * Get a single {@link Annotation} of {@code annotationType} from the supplied
 	 * annotation: either the given annotation itself or a direct meta-annotation

spring-orm/src/main/java/org/springframework/orm/jpa/AbstractEntityManagerFactoryBean.java

@@ -261,6 +261,11 @@ public void setEntityManagerInterface(@Nullable Class<? extends EntityManager> e
 		return this.entityManagerInterface;
 	}
 
+	@Override
+	public @Nullable Class<?> getEntityAgentInterface() {
+		return this.entityAgentInterface;
+	}
+
 	/**
 	 * Specify the vendor-specific JpaDialect implementation to associate with
 	 * this EntityManagerFactory. This will be exposed through the
@@ -419,8 +424,7 @@ public void afterPropertiesSet() throws PersistenceException {
 
 		this.sharedEntityManager = SharedEntityManagerCreator.createSharedEntityManager(this.entityManagerFactory);
 		if (this.entityAgentInterface != null) {
-			this.sharedEntityAgent = SharedEntityManagerCreator.createSharedEntityAgent(
-					this.entityManagerFactory, null, this.entityAgentInterface);
+			this.sharedEntityAgent = SharedEntityManagerCreator.createSharedEntityAgent(this.entityManagerFactory);
 		}
 	}
 

spring-orm/src/main/java/org/springframework/orm/jpa/EntityManagerFactoryInfo.java

@@ -83,6 +83,16 @@ public interface EntityManagerFactoryInfo {
 	 */
 	@Nullable Class<? extends EntityManager> getEntityManagerInterface();
 
+	/**
+	 * Return the (potentially vendor-specific) EntityAgent interface
+	 * that this factory's EntityAgents will implement.
+	 * <p>A {@code null} return value suggests that autodetection is supposed
+	 * to happen: either based on a target {@code EntityAgent} instance
+	 * or simply defaulting to {@code jakarta.persistence.EntityAgent}.
+	 * @since 7.1
+	 */
+	@Nullable Class<?> getEntityAgentInterface();
+
 	/**
 	 * Return the vendor-specific JpaDialect implementation for this
 	 * EntityManagerFactory, or {@code null} if not known.

spring-orm/src/main/java/org/springframework/orm/jpa/EntityManagerFactoryUtils.java

@@ -380,10 +380,12 @@ static Object createEntityAgent(EntityManagerFactory emf, @Nullable Map<?, ?> pr
 
 	/**
 	 * Determine the {@code jakarta.persistence.EntityAgent} class.
-	 * @return the {@code EntityAgent} class, or {@code null} if not available
-	 * @since 7.0.4
+	 * <p>Intended for internal adaptation to JPA 3.2 vs 4.0.
+	 * @return the {@code EntityAgent} class (on JPA 4.0),
+	 * or {@code null} if not available (on JPA 3.2)
+	 * @since 7.1
 	 */
-	static @Nullable Class<?> getEntityAgentClass() {
+	public static @Nullable Class<?> getEntityAgentClass() {
 		return (CREATE_ENTITY_AGENT_METHOD != null ? CREATE_ENTITY_AGENT_METHOD.getReturnType() : null);
 	}
 

spring-orm/src/main/java/org/springframework/orm/jpa/SharedEntityManagerCreator.java

@@ -38,6 +38,7 @@
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.transaction.support.TransactionSynchronizationManager;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.ConcurrentReferenceHashMap;
@@ -177,19 +178,38 @@ public static EntityManager createSharedEntityManager(EntityManagerFactory emf,
 				ifcs, new SharedEntityManagerInvocationHandler(emf, properties, synchronizedWithTransaction));
 	}
 
+	/**
+	 * Create a transactional EntityAgent proxy for the given EntityManagerFactory.
+	 * @param emf the EntityManagerFactory to obtain EntityAgents from as needed
+	 * @return a shareable transactional EntityAgent proxy
+	 * (typed to {@code Object} for compatibility with JPA 3.2; this will change
+	 * to {@code EntityAgent} once Spring establishes a JPA 4.0 minimum baseline)
+	 * @since 7.1
+	 */
+	public static Object createSharedEntityAgent(EntityManagerFactory emf) {
+		return createSharedEntityAgent(emf, null);
+	}
+
 	/**
 	 * Create a transactional EntityAgent proxy for the given EntityManagerFactory.
 	 * @param emf the EntityManagerFactory to obtain EntityAgentss from as needed
 	 * @param properties the properties to be passed into the
 	 * {@code createEntityAgent} call (may be {@code null})
-	 * @param ifc the interfaces to be implemented by the EntityAgent
 	 * @return a shareable transactional EntityAgent proxy
-	 * @since 7.0.4
+	 * (typed to {@code Object} for compatibility with JPA 3.2; this will change
+	 * to {@code EntityAgent} once Spring establishes a JPA 4.0 minimum baseline)
+	 * @since 7.1
 	 */
-	static Object createSharedEntityAgent(EntityManagerFactory emf, @Nullable Map<?, ?> properties, Class<?> ifc) {
+	public static Object createSharedEntityAgent(EntityManagerFactory emf, @Nullable Map<?, ?> properties) {
 		ClassLoader cl = null;
+		Class<?> ifc = null;
 		if (emf instanceof EntityManagerFactoryInfo emfInfo) {
 			cl = emfInfo.getBeanClassLoader();
+			ifc = emfInfo.getEntityAgentInterface();
+		}
+		if (ifc == null) {
+			ifc = EntityManagerFactoryUtils.getEntityAgentClass();
+			Assert.state(ifc != null, "JPA 4.0 EntityAgent class not found");
 		}
 		return Proxy.newProxyInstance(
 				(cl != null ? cl : SharedEntityManagerCreator.class.getClassLoader()),