so, it looks like your entity code is OK. you just need to add an extra step when saving: PartyIsPerson p = new PartyIsPerson(); | p.setUsername("Guest"); //Guest | p.setPassword("Guest"); //Guest | p.setForename("Guest"); //Guest | p.setLastname("Guest"); //Guest | p.setPartyId(100); | | PersonHasCustomization phc = new PersonHasCustomization(); | phc.setPartyidperson(p.getPartyId()); | phc.setLocale("DE_de"); | p.setCustomization(phc); | | EntityManager.persist(p) from the "Java Persistence w/Hibernate" book it says, JPA doesn't include a standard way of dealing with shared primary key generation. So, it's up to you to set it (page 282). View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4082403#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...