EntityManager#lock throws throws OptimisticLockException using LockModeType.PESSIMISTIC_WRITE if entity doesn't exist in dataase

An easy way to reproduce this issue (using FlushMode.AUTO) is:

Surprisingly, when executing a query for the TestEntity before calling entityManager.lock, no exception will be thrown. The reason for that is, that, when calling SessionImpl.list, SessionImpl will check if a flush is necessary and flush when needed.
Could this code (check and autoflush) maybe be used in entityManager.lock too?

From Stephen Fikes:

“Aside from lock(), I think there is also an issue with EntityManager.find(...) which raises OptimisticLockException when using javax.persistence.LockModeType.PESSIMISTIC_WRITE (whether or not the entity has an optimistic version property). Per the JavaDoc [1] think it is supposed to be a PessimisticLockException (at least when not using a version property - not sure if it should differ when using a version property).”