Now I have trouble with persistence.xml . In my application : FMK-EAR --> fmk.war ( seam 2.2 ) PLATFORM CONSOLE --> fmk-seam.jar (ejb) ( My seam's basic actions ) --> fmk-serviceEjb.jar (ejb) ( My plattaform services ) --> fmk-entities.jar (ejb/persistence) ( My basic plattaform entities / persitence unit) Case 1 : If I put the file persistence.xml in the FMK-EAR/META-INF , I have the error : ClassNotFound http://www.jboss.org/index.html?module=bb&op=viewtopic&t=161236 Case 2 : If I put the file persistence.xml in the fmk-entities.jar , I have the error in fmk-serviceEjb.jar with @EntityPersister(name="ejb3FMK") , error : PersistenceUnit ejbFMK not found . Appreciate any help ! View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4255176#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...