HibernateJpaVendorAdapter and LocalSessionFactoryBuilder enforce Hibernate 5.2's connection handling mode DELAYED_ACQUISITION_AND_HOLD

Issue: SPR-14393

spring-orm-hibernate5/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java

@@ -235,7 +235,6 @@ public class HibernateTransactionManager extends AbstractPlatformTransactionMana
 	 * <p>Default is "false". Turning this flag on enforces over-commit holdability on the
 	 * underlying JDBC Connection (if {@link #prepareConnection "prepareConnection"} is on)
 	 * and skips the disconnect-on-completion step.
-	 * @since 4.2
 	 * @see Connection#setHoldability
 	 * @see ResultSet#HOLD_CURSORS_OVER_COMMIT
 	 * @see #disconnectOnCompletion(Session)
@@ -689,7 +688,6 @@ public class HibernateTransactionManager extends AbstractPlatformTransactionMana
 	 * <p>The default implementation simply calls {@link Session#disconnect()}.
 	 * Subclasses may override this with a no-op or with fine-tuned disconnection logic.
 	 * @param session the Hibernate Session to disconnect
-	 * @since 4.2
 	 * @see Session#disconnect()
 	 */
 	protected void disconnectOnCompletion(Session session) {

spring-orm-hibernate5/src/main/java/org/springframework/orm/hibernate5/LocalSessionFactoryBuilder.java

@@ -139,6 +139,10 @@ public class LocalSessionFactoryBuilder extends Configuration {
 		if (dataSource != null) {
 			getProperties().put(Environment.DATASOURCE, dataSource);
 		}
+
+		// Hibernate 5.2: manually enforce connection release mode ON_CLOSE (the former default)
+		getProperties().put("hibernate.connection.handling_mode", "DELAYED_ACQUISITION_AND_HOLD");
+
 		getProperties().put(AvailableSettings.CLASSLOADERS, Collections.singleton(resourceLoader.getClassLoader()));
 		this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
 	}
@@ -157,6 +161,7 @@ public class LocalSessionFactoryBuilder extends Configuration {
 	 */
 	public LocalSessionFactoryBuilder setJtaTransactionManager(Object jtaTransactionManager) {
 		Assert.notNull(jtaTransactionManager, "Transaction manager reference must not be null");
+
 		if (jtaTransactionManager instanceof JtaTransactionManager) {
 			boolean webspherePresent = ClassUtils.isPresent("com.ibm.wsspi.uow.UOWManager", getClass().getClassLoader());
 			if (webspherePresent) {
@@ -182,6 +187,10 @@ public class LocalSessionFactoryBuilder extends Configuration {
 			throw new IllegalArgumentException(
 					"Unknown transaction manager type: " + jtaTransactionManager.getClass().getName());
 		}
+
+		// Hibernate 5.2: manually enforce connection release mode AFTER_STATEMENT (the JTA default)
+		getProperties().remove("hibernate.connection.handling_mode", "DELAYED_ACQUISITION_AND_RELEASE_AFTER_STATEMENT");
+
 		return this;
 	}
 

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

@@ -126,7 +126,7 @@ public class HibernateJpaDialect extends DefaultJpaDialect {
 	}
 
 
-	private boolean prepareConnection = (HibernateConnectionHandle.sessionConnectionMethod == null);
+	boolean prepareConnection = (HibernateConnectionHandle.sessionConnectionMethod == null);
 
 
 	/**
@@ -362,25 +362,15 @@ public class HibernateJpaDialect extends DefaultJpaDialect {
 			}
 			if (this.preparedCon != null && this.session.isConnected()) {
 				Connection conToReset = HibernateConnectionHandle.doGetConnection(this.session);
-				if (!isEquivalentConnection(conToReset)) {
+				if (conToReset != this.preparedCon) {
 					LogFactory.getLog(HibernateJpaDialect.class).warn(
-							"JDBC Connection to reset not equivalent to originally prepared Connection - please " +
+							"JDBC Connection to reset not identical to originally prepared Connection - please " +
 							"make sure to use connection release mode ON_CLOSE (the default) and to run against " +
 							"Hibernate 4.2+ (or switch HibernateJpaDialect's prepareConnection flag to false");
 				}
 				DataSourceUtils.resetConnectionAfterTransaction(conToReset, this.previousIsolationLevel);
 			}
 		}
-
-		private boolean isEquivalentConnection(Connection con) {
-			try {
-				return (con.equals(this.preparedCon) ||
-						con.unwrap(Connection.class).equals(this.preparedCon.unwrap(Connection.class)));
-			}
-			catch (Throwable ex) {
-				return false;
-			}
-		}
 	}
 
 

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

@@ -101,6 +101,27 @@ public class HibernateJpaVendorAdapter extends AbstractJpaVendorAdapter {
 	}
 
 
+	/**
+	 * Set whether to prepare the underlying JDBC Connection of a transactional
+	 * Hibernate Session, that is, whether to apply a transaction-specific
+	 * isolation level and/or the transaction's read-only flag to the underlying
+	 * JDBC Connection.
+	 * <p>See {@link HibernateJpaDialect#setPrepareConnection(boolean)} for details.
+	 * This is just a convenience flag passed through to {@code HibernateJpaDialect}.
+	 * <p>On Hibernate 5.2, this flag remains {@code true} by default like against
+	 * previous Hibernate versions. The vendor adapter manually enforces Hibernate's
+	 * new connection handling mode {@code DELAYED_ACQUISITION_AND_HOLD} in that case
+	 * unless a user-specified connection handling mode property indicates otherwise;
+	 * switch this flag to {@code false} to avoid that interference.
+	 * @since 4.3.1
+	 * @see #getJpaPropertyMap()
+	 * @see HibernateJpaDialect#beginTransaction
+	 */
+	public void setPrepareConnection(boolean prepareConnection) {
+		this.jpaDialect.setPrepareConnection(prepareConnection);
+	}
+
+
 	@Override
 	public PersistenceProvider getPersistenceProvider() {
 		return this.persistenceProvider;
@@ -132,6 +153,11 @@ public class HibernateJpaVendorAdapter extends AbstractJpaVendorAdapter {
 			jpaProperties.put(Environment.SHOW_SQL, "true");
 		}
 
+		if (this.jpaDialect.prepareConnection) {
+			// Hibernate 5.2: manually enforce connection release mode ON_CLOSE (the former default)
+			jpaProperties.put("hibernate.connection.handling_mode", "DELAYED_ACQUISITION_AND_HOLD");
+		}
+
 		return jpaProperties;
 	}