I have forgotten something: You forgot to mark the boundries of the transaction scope correctly. The transaction scope is importend, because the entitymanager persists the entities if he leaves the transaction scope. The boundries are marked by the begin() and commit() method. You forgot the begin method. The corrected code: | (...) | ut.begin(); //start of the transaction scope | a.setName("F002"); | em.merge(a) // better: a = em.merge(a) | ut.commit(); //end of the transaction scope: a is persisted at this point | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3986674#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...