Upgraded to Hibernate 4.2.0

HibernateJpaDialect's HibernateConnectionHandle does not call close() for Hibernate 4.x anymore, since on 4.2, the exposed Connection handle isn't a "borrowed connection" wrapper but rather the actual underlying Connection - with a close() call immediately returning the Connection to the pool and making the local handle invalid for further use within the transaction.

Also using JPA 2.0's EntityManager unwrap method now for retrieving the underlying Hibernate Session.

Issue: SPR-10395

build.gradle

@@ -502,8 +502,8 @@ project("spring-orm-hibernate4") {
 	dependencies {
 		provided(project(":spring-tx"))
 		provided(project(":spring-jdbc"))
-		optional("org.hibernate:hibernate-core:4.1.9.Final")
-		optional("org.hibernate:hibernate-entitymanager:4.1.9.Final")
+		optional("org.hibernate:hibernate-core:4.2.0.Final")
+		optional("org.hibernate:hibernate-entitymanager:4.2.0.Final")
 		optional(project(":spring-web"))
 		optional("javax.servlet:javax.servlet-api:3.0.1")
 	}
@@ -751,7 +751,7 @@ configure(rootProject) {
 		testCompile(project(":spring-web"))
 		testCompile(project(":spring-webmvc-portlet"))
 		testCompile(project(":spring-orm"))
-		testCompile("org.hibernate:hibernate-core:4.1.9.Final")
+		testCompile("org.hibernate:hibernate-core:4.2.0.Final")
 		testCompile("javax.servlet:javax.servlet-api:3.0.1")
 		testCompile("javax.portlet:portlet-api:2.0")
 		testCompile("javax.inject:javax.inject:1")

spring-orm/src/main/java/org/springframework/orm/jpa/vendor/HibernateJpaDialect.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,7 +25,6 @@
 import org.hibernate.FlushMode;
 import org.hibernate.HibernateException;
 import org.hibernate.Session;
-import org.hibernate.ejb.HibernateEntityManager;
 
 import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.datasource.ConnectionHandle;
@@ -35,6 +34,7 @@
 import org.springframework.orm.jpa.EntityManagerFactoryUtils;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionException;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
 /**
@@ -106,19 +106,7 @@ public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 	}
 
 	protected Session getSession(EntityManager em) {
-		if (em instanceof HibernateEntityManager) {
-			return ((HibernateEntityManager) em).getSession();
-		}
-		else {
-			Object delegate = em.getDelegate();
-			if (delegate instanceof Session) {
-				return (Session) delegate;
-			}
-			else {
-				throw new IllegalStateException(
-						"Cannot obtain native Hibernate Session from given JPA EntityManager: " + em.getClass());
-			}
-		}
+		return em.unwrap(Session.class);
 	}
 
 
@@ -145,27 +133,38 @@ private static class HibernateConnectionHandle implements ConnectionHandle {
 
 		private final Session session;
 
-		private static volatile Method connectionMethod;
+		// This will find a corresponding method on Hibernate 3.x but not on 4.x
+		private static final Method sessionConnectionMethod =
+				ClassUtils.getMethodIfAvailable(Session.class, "connection");
+
+		private static volatile Method connectionMethodToUse = sessionConnectionMethod;
 
 		public HibernateConnectionHandle(Session session) {
 			this.session = session;
 		}
 
 		public Connection getConnection() {
 			try {
-				if (connectionMethod == null) {
-					// reflective lookup to bridge between Hibernate 3.x and 4.x
-					connectionMethod = this.session.getClass().getMethod("connection");
+				if (connectionMethodToUse == null) {
+					// Reflective lookup trying to find SessionImpl's connection() on Hibernate 4.x
+					connectionMethodToUse = this.session.getClass().getMethod("connection");
 				}
-				return (Connection) ReflectionUtils.invokeMethod(connectionMethod, this.session);
+				return (Connection) ReflectionUtils.invokeMethod(connectionMethodToUse, this.session);
 			}
 			catch (NoSuchMethodException ex) {
-				throw new IllegalStateException("Cannot find connection() method on Hibernate session", ex);
+				throw new IllegalStateException("Cannot find connection() method on Hibernate Session", ex);
 			}
 		}
 
 		public void releaseConnection(Connection con) {
-			JdbcUtils.closeConnection(con);
+			if (sessionConnectionMethod != null) {
+				// Need to explicitly call close() with Hibernate 3.x in order to allow
+				// for eager release of the underlying physical Connection if necessary.
+				// However, do not do this on Hibernate 4.2+ since it would return the
+				// physical Connection to the pool right away, making it unusable for
+				// further operations within the current transaction!
+				JdbcUtils.closeConnection(con);
+			}
 		}
 	}