Hmm, when I build the ear via ant, the exception is different than the one I previously posted which was built from eclipse. I guess the difference is that no hibernate jars are in the classpath when building with ant (I have no direct compile dependencies). | Caused by: java.lang.NullPointerException | at org.hibernate.cfg.OneToOneSecondPass.doSecondPass(OneToOneSecondPass.java:135) | at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1130) | at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:296) | at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1115) | at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1233) | at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:154) | at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:869) | at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:183) | at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:240) | ... 61 more | p.s. You are correct in assuming my war does not include any hibernate jars. They are only in the lib directory of the ear. justin. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4170808#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...