I have 2 jar files. The first one is dao and the second one is domain logic. After deployment DAO sets own persistence unit. But when I'm trying to get reference on it from domain.jar: anonymous wrote : @PersistenceContext(unitName = "name_from_dao") | private EntityManager manager; Jboss issue is Persistence Unit NOTYETINSTALLED After putting classes from domain.jar to dao.jar, deployment successful. What's the cause of this bug? Maybe I must add someone additional deployment descriptor to domain.jar? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3989937#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...