JTATransactionFactory and JTA transaction behavior/problem

titou09 · **Joined:** Fri Jan 27, 2006 11:34 am **Posts:** 5

Hibernate version: 3.1.1
Application Server: WebSphere 6.0.2.5
Fragment of hibernate.cfg.xml

Code:

<property name="current_session_context_class">org.hibernate.context.JTASessionContext</property> 
<property name="transaction.factory_class">org.hibernate.transaction.JTATransactionFactory</property>
<property name="transaction.manager_lookup_class">org.hibernate.transaction.WebSphereExtendedJTATransactionLookup</property>

This code (Inside a servlet) works :

Code:

 UserTransaction tx = (UserTransaction)newInitialContext().lookup("java:comp/UserTransaction");
 tx.begin();
 Session session = sessionFactory.getCurrentSession();
 // Do some hibernate stuff here
 tx.commit();

This (Inside a servlet) does not:

Code:

Session session = sessionFactory.getCurrentSession();
 Transaction tx = session.beginTransaction();
 // Do some hibernate stuff here
 tx.commit();

It fails on getCurrentSession() with:

Code:

org.hibernate.HibernateException: Current transaction is not in progress

In the doc, it is stated (section 3.8.1) that:
"org.hibernate.transaction.JTATransactionFactory delegates to container-managed transaction if an existing transaction is underway in this context (e.g. EJB session bean method), otherwise a new transaction is started and bean-managed transaction are used."

But this does not seems to work as expected. Obvisouly, for the failing case, there is no JTA transaction running, and calling Session.getCurrentSession() does not start a new one

Q:
1) Am I doing something wrong (config or code)?
2) Is the doc wrong?
3) Is it a bug?

LaLiLuna · **Posted:** Fri Jan 27, 2006 12:44 pm

no it is not a bug. Using EJB the transaction would be injected. Using simple Hibernate using JTA would will need to start a session. So you should call openSession instead of currentSession.
See my question to this topic a couple of days ago.

Regards Sebastian

titou09 · **Joined:** Fri Jan 27, 2006 11:34 am **Posts:** 5

Thanks Sebastian for your answer. I've read your post (15 jan 2006) and the answers...and your solution seems to work but does not fully satisfy me...lol

In the doc, section 3.8.3, it is stated:...Using the "jta" session context, if there is no Hibernate Session associated with the current JTA transaction, one will be started and associated with that JTA transaction the first time you call sessionFactory.getCurrentSession()..
However, this section does not tell what happens when there is no JTA transaction in progress...

My understanding and experimentations with "jta" session context:

In both cases, the Transaction object returned by session.beginTransaction() should deal with the underlying JTA Transaction (commits, rollbacks).

What's still not clear to me:
- if the JTA transaction has been started because of a call to openSession(), will it be closed when calling: a) session.close() or b) tx.commit()?
of tx.commit()? close/commit the JTA transaction? (I understand that directly or indirectly calling UserTransaction.commit() will trigger some "commit callbacks" in the attached Hibernate session and transaction)
- if the session (re)used the JTA transaction in progress, what is the effect

What I will do is, as suggested in section 11.1.1 and by some user in this forum, is:
- use a filter to manage session.openSession() and session.close()
- use BMT for EJBs session facades that will call session.openSession(), then business/objects methods, and session.close()
- use session.getCurrentSession() anywhere else in the code

I would suggest having a table or two in the documentation explaining how the instances of UserTransaction, Session and Transaction interact in a jta environment. The tables could explain the effects of calling methods like session.openSession(), session.currentSession(), session.close(), transaction.commit(), UserTransaction.commit(), and this, if a JTA Transaction is in progress or not or if it has been started by Hibernate....etc. I thing this should be of great help (At least for me..)

And BTW Congratulations to everybody implied with the design/development of Hibernate. This product is fantastic..Thanks a lot