[net.sf.hibernate.engine.CacheSynchronization] transaction before completion callback
[org.jboss.resource.connectionmanager.CachedConnectionManager] Closing a connection for you. 
Please close them yourself: org.jboss.resource.adapter.jdbc.WrappedConnection@db95a1
java.lang.Exception: STACKTRACE
        at org.jboss.resource.connectionmanager.CachedConnectionManager.registerConnection(CachedConnectionManager.java:282)
        at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:506)
        at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:814)
        at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:122)
        at net.sf.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:56)
        at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:278)
        at net.sf.hibernate.impl.SessionImpl.connect(SessionImpl.java:3264)
        at net.sf.hibernate.impl.SessionImpl.connection(SessionImpl.java:3244)
        at net.sf.hibernate.impl.BatcherImpl.prepareStatement(BatcherImpl.java:61)
        at net.sf.hibernate.persister.EntityPersister.insert(EntityPersister.java:524)
        at net.sf.hibernate.persister.EntityPersister.insert(EntityPersister.java:432)
        at net.sf.hibernate.impl.ScheduledIdentityInsertion.execute(ScheduledIdentityInsertion.java:29)
        at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:906)

        ---o<--- code snipped for brevity ---

        try {
            session = HibernateSession.currentSession();
            tx = session.beginTransaction();                   

            // do some session.save here ...

            session.flush();
                       
        } catch(HibernateException he) {
            if (session.isConnected()) {
                try {
                    if (!tx.wasRolledBack())
                        tx.rollback();
                } catch (HibernateException he2) {
                    throw new EJBException(he);   
                }                       
            }
            throw new EJBException(he);
        } finally {
            HibernateSession.closeSession();
        }