Question

I’m working with EJBs…I do the following and I don’t know why the injected EntityManager is not working as one might expect.

1. EJB1 calls a method on EJB2 that writes to the DB.
2. when EJB2 returns EJB1 sends a message to a MDB.
3. MDB calls EJB3 that reads the DB and does some work.

My problem is that the EntityManager injected in all 3 EJBs with @PersistenceContext is not working properly. Calling persist() in EJB2 is not being reflected on the EntityManager injected in EJB3.
What might be wrong?
Hope I made my problem clear enough.
now working with Container managed transactions.

Answer 1

My problem is that the EntityManager injected in all 3 EJBs with @PersistenceContext is not working properly. Calling persist() in EJB2 is not being reflected on the EntityManager injected in EJB3.

In a Java EE environment, the common case is to use a Transaction-Scoped Container-Managed entity manager. And with such an entity manager, the persistence context propagates as the JTA transaction propagates.

In your case, I suspect you’re using a REQUIRES_NEW transaction attribute for the method of EJB3. So:

• when invoking EJB3#bar(), the container will suspend the transaction started for EJB2#foo() and start a new transaction
• when invoking the entity manager from EJB3#bar(), a new persistence context will be created.
• since the transaction started for EJB2#foo() has not yet committed, changes aren’t “visible” to the new persistence context.

PS: Are you really creating new threads? If yes, little reminder: this is forbidden by the EJB spec.