Hi If I try to build a SessionFactory for annotated classes AnnotationConfiguration cfg = new AnnotationConfiguration(); | cfg.addAnnotatedClass(mypackage.MyAnnotatedEntity.class); | SessionFactory sessionFactory = cfg.buildSessionFactory(); (or if I try with an xml-configuration instead the above code) I get always this error: java.lang.IllegalAccessError: tried to access method org.hibernate.cfg.Mappings.(Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/List;Ljava/util/List;Lorg/hibernate/cfg/NamingStrategy;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/List;Ljava/util/Map;Ljava/util/Map;)V from class org.hibernate.cfg.ExtendedMappings at org.hibernate.cfg.ExtendedMappings.(ExtendedMappings.java:65) at org.hibernate.cfg.AnnotationConfiguration.createExtendedMappings(AnnotationConfiguration.java:175) at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:263) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1210) at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:915) I use the latest Hibernate and Hibernate-Annotations. I deployed the latest hibernate3.jar to /server/all/lib and hibernate-annotations.jar, hibernate-commons-annotations.jar, ejb3-persistence.jar to /server/all/farm. The same code works perfectly in a standalone-environment (no JBoss, just a VM for JUnit-Tests). So it cannot be a incompatibility between Hibernate and Hibernate-Annotations. Thanks for any help Andreas View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4043259#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...