Question

I am new to JPA 2.0 locking, so it might be I am missing something.

Using NetBeans, I tried to debug a Stateless Session Bean. I tried to switch between two threads to examine the concept:

   em.lock(entity, LockModeType.PESSIMISTIC_WRITE);
    em.persist(entity);
    try {
        em.flush();
    } catch (Exception e) {
        System.out.println("Already Locked!");
    }

I let the first process to finish

em.flush();

(no exceptions). Then, I switched to the second process. Surprisingly – it paused after the first line, and continued only after the first process exited the function.

Note: It was all working as expected with LockModeType.OPTIMISTIC.

Is it a normal behavior? am I missing something? here it seems to behave in a different way.

Thanks,

Danny

Answer 1

It is perfectly normal behavior. Lock is released in transaction commit/rollback and that is not happening as a consequence of calling em.flush().