I am modifying an application where an ancestor class is persisted before asking the user what type he wants to use, where some types are descendant classes. Once a class is persisted, is it possible to modify the class type to be a descendant class? For example, class Pet{} class Dog extends Pet{} ..... Pet p = new Pet(); entityManager.persist(p); ..... Dog d = new Pet(p); ??? entityManager.persist(d); In general, I can't find a lot of information about how to use inheritance withc EJB3. Can anyone point me to some good links? TIA View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3981149#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...