relates to hibernate version 3.2.2 used within tomcat 5.5 and spring 2.0.2

Since I found out, that the transaction progragation "requires new" only works with a JTA transaction manager I tried to used the JOTM implementation and setup my hibernate session factory according to the examples I found in the spring docs.

At a first glance my app seems to operate as normal but sometimes I see a Nullpointer execption in the method

registerSynchronization() in class org.hibernate.transaction.JTATransaction

The code found there

try { getTransactionManager().getTransaction().registerSynchronization(sync);
}
catch (Exception e) {
throw new TransactionException("could not register synchronization", e);
}

assumes that there is always a transaction associated with the current thread (getTransaction() never returns null)

I wonder if my configuration is wrong or what might be the reason behind that assumption ?

Any help and hints appreciated,

Dirk