Previously Hibernate had an issue in which `EntityManager.flush()` did not behave properly with a transient one-to-one association and no cascade. In this situation it is expected that an `IllegalStateException` will be thrown by the flush operation and the transaction marked for rollback, or the transaction commit will fail. This issue has been fixed in this release of JBoss Web Server by upgrading Hibernate to 4.2.18.Final-redhat-1, and `EntityManager.flush()` operations will now behave as expected in situations of a transient one-to-one association and no cascade.