[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-5550) Hibernate.createBlob() fails when used in current_session_context_class=thread mode

[Zemian Deng (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-5550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=39499#action_39499 ] 

Zemian Deng commented on HHH-5550:
----------------------------------

Hi there,

Yes the 3.6 version with "session.getLobHelper().createBlob( bytes )" does works. Thanks.

I have two additional feedbacks though:
1) In 3.6, even Hibernate.createBlob(blobBytes, session); is marked as deprecated, but if used, it still produces the same exception mentioned here. So in this case, it's not just deprecated, but it's broken. (Granted that it only for Thread context scenerio, but still a bit annoying.).

2) In 3.6, the javadoc on Hibernate.createBlob(blobBytes, session) says: "@deprecated Use {@link LobHelper#createBlob(byte[])} instead." Now this is not very good hint since LobHelper is an interface and the only implementation is a private inner class. It would be more helpful to let user know that they need to get this impl instance by session instance like "session.getLobHelper().createBlob( bytes )".

Hope this helps,
Zemian Deng



> Hibernate.createBlob() fails when used in current_session_context_class=thread mode
> -----------------------------------------------------------------------------------
>
>                 Key: HHH-5550
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5550
>             Project: Hibernate Core
>          Issue Type: Bug
>    Affects Versions: 3.5.5
>            Reporter: Zemian Deng
>            Assignee: Steve Ebersole
>             Fix For: 3.6.1
>
>
> See https://forum.hibernate.org/viewtopic.php?f=1&t=1004366
> Here is a unit test failed case:
> {code:java}
> package deng.hibernate.examples.blob;
> import org.hibernate.*;
> import org.hibernate.cfg.*;
> import org.junit.Test;
> public class HibernateCreateBlobFailedCase {
> 		
> 	@Test
> 	public void createBlob() {
> 		Configuration cfg = new Configuration();
> 		SessionFactory sessionFactory = cfg.configure().buildSessionFactory();
> 		Session session = sessionFactory.getCurrentSession();
> 		Transaction tx = null;
> 		try {
> 			tx = session.beginTransaction();
> 			byte[] blobBytes = new byte[]{};
> 			Hibernate.createBlob(blobBytes, session);
> 		} catch (Throwable e) {
> 			tx.rollback();
> 			throw new RuntimeException(e);
> 		} finally {
> 			sessionFactory.close();
> 		}
> 	}
> 	
> }
> {code}
> Set hibernate.cfg.xml with thread session context
> {code:xml}
> ...
> <property name="current_session_context_class">thread</property>
> ...
> {code}
> You will get this stack trace
> {noformat}
> java.lang.RuntimeException: java.lang.ClassCastException: $Proxy4 cannot be cast to org.hibernate.engine.jdbc.LobCreationContext
> 	at deng.hibernate.examples.blob.HibernateCreateBlobFailedCase.createBlob(HibernateCreateBlobFailedCase.java:24)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> 	at java.lang.reflect.Method.invoke(Method.java:597)
> 	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
> 	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
> 	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
> 	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
> 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
> 	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
> 	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
> 	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
> 	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
> 	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
> 	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
> 	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
> 	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
> 	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
> 	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
> Caused by: java.lang.ClassCastException: $Proxy4 cannot be cast to org.hibernate.engine.jdbc.LobCreationContext
> 	at org.hibernate.Hibernate.getLobCreator(Hibernate.java:502)
> 	at org.hibernate.Hibernate.getLobCreator(Hibernate.java:498)
> 	at org.hibernate.Hibernate.createBlob(Hibernate.java:494)
> 	at deng.hibernate.examples.blob.HibernateCreateBlobFailedCase.createBlob(HibernateCreateBlobFailedCase.java:21)
> 	... 22 more
> {noformat}
> As described in forum, this problem occurred because the session object we get using {{sessionFactory.getCurrentSession();}} is an wrapped ThreadLocalSessionContext instance that can not be cast into LobCreationContext. There is no easy way to unwrap and get the original session object, to pass to createBlob method.

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