Actually this caused another problem. The solution I used fixed the problem when persisting but later when I try to retrieve a Season with a query I get: | org.hibernate.exception.GenericJDBCException: Cannot open connection | Caused by: javax.resource.ResourceException: Transaction is not active: tx=TransactionImple < ac, BasicAction: -53eff9c9:88e:46cd9 | 8c3:ab status: ActionStatus.ABORT_ONLY | What am I actually doing when I replace @JoinColumn with a mappedBy? ;) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4077368#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...