I had a similar problem with two jars in the same ear. To resolve it I had to import the classes from DEF.jar into ABC.jar via the persistence.xml file in ABC.jar ABC.jar/META-INF/persistence.xml | <persistence> | <persistence-unit name="my2ndPU"> | <jta-data-source>java:/MyDS</jta-data-source> | <class>com.myCo.MyClassInDEF</class> | ... | </persistence-unit> | </persistence> | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4116513#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...