Hi Thanks for your help. I've got a solution for this problem. The culprit was here the file below, | <mapping-file>com/pioneer/riskbudgeting/dao/accesscontrol/hbm/accesscontrol.hbm.xml</mapping-file> | as described here http://docs.jboss.org/ejb3/app-server/reference/build/reference/en/html/h... any files with extension hbm.xml in the classpath will be added to the hibernate config. So while we changed the order of classes within accesscontrol.hbm.xml to check invidual classes weren't duplicates, all classes in there were being duplicated. Perhaps if the file is listed in the <mapping-file> of persistence.xml it shouldn't be then loaded again by JBoss. Cheers Nick. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4102610#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...