I tried to do as you adviced but I get the following error on jboss4.2.2-GA [Configuration] Reading mappings from resource : persistence-mapping-file.xml 10:02:10,488 ERROR [AbstractKernelController] Error installing to Start: name=persistence.units:unitName=NewsCrawlerPu state=Create javax.persistence.PersistenceException: [PersistenceUnit: NewsCrawlerPu] Unable to find XML mapping file in classpath: ../persistence-mapping-file.xml at org.hibernate.ejb.Ejb3Configuration.addClassesToSessionFactory(Ejb3Configuration.java:892) I want to deploy a ear file containing a WAR and JAR archives.I inserted the persistence.xml both in the WAR and JAR (under WEB-INF and META-INF respectively), do I have to ass it also to the classpath on the Manifest of the archives? Flavio View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4116953#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...