Create and find a jpa entity in the same transaction?

Question

I'm using JBoss 7.1.1 and the default implementation of Hibernate that comes with it (4.0.1). I have a message driven bean, that in the same transaction creates an entity and persists it using the entity manager. After that (still the same transaction) I find the newly created entity and try to use the entity manager to lock it with PESSIMISTIC_WRITE, but I get an OptimisticLockException. Its root is as follows:

Caused by: org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [some.package.name.EntityName#aaa1a1a0-d568-11e1-9f99-d5a00a0a12b6]
    at org.hibernate.dialect.lock.PessimisticWriteSelectLockingStrategy.lock(PessimisticWriteSelectLockingStrategy.java:95)
    at org.hibernate.persister.entity.AbstractEntityPersister.lock(AbstractEntityPersister.java:1785)
    at org.hibernate.event.internal.AbstractLockUpgradeEventListener.upgradeLock(AbstractLockUpgradeEventListener.java:99)
    at org.hibernate.event.internal.DefaultLockEventListener.onLock(DefaultLockEventListener.java:85)
    at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:693)
    at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:686)
    at org.hibernate.internal.SessionImpl.access$1100(SessionImpl.java:160)
    at org.hibernate.internal.SessionImpl$LockRequestImpl.lock(SessionImpl.java:2164)
    at org.hibernate.ejb.AbstractEntityManagerImpl.lock(AbstractEntityManagerImpl.java:1093)
    ... 202 more

Any ideas why I can't look up the newly created entity? Also, how can I make it available for searching right after it is created? Using the merge method of the EM doesn't seem to help ...

Answer 1

My understanding of your question is that within your message driven bean's transaction you're doing the following:

1. Create entityA
2. Persist entityA
3. entityB = find entityA
4. lock(entityB, PESSIMISTIC_WRITE)

and step 4 is throwing an exception.

I think Hibernate may not have flushed the persist between 2 and 3 so at that point A (and B) have version 0. Hibernate is then flushing the persist of A at the start of the lock(), which means B now has a stale version.

You could try flushing the persist before the find (so entityManager.flush() after 2).

Or you should be able to skip the find, since entityManager.persist(entityA) makes entityA a managed object, so the following sequence may work:

1. Create entityA
2. Persist entityA
3. lock(entityA, PESSIMISTIC_WRITE)