Good morning rvkishore, Thanks a lot for your reply. It seems that reference objects retrieved using <framework:entity-query> and using entityManager.createQuery() are different, possibly due to different memory location. An equals() method of the reference class also helps to solve the "value is invalid" error. Basically it check the Id and returns true if ids of two reference objects are the same. Have a nice day! Best regards, Sheng View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4109850#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...