Hibernate 4.1.5.SP1 is not compatible with Java 1.5, it throws java.lang.UnsupportedClassVersionError: org/hibernate/ejb/HibernatePersistence : unsupported classversion 50.0 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Key: HIBERNATE-136 URL: https://issues.jboss.org/browse/HIBERNATE-136 Project: Hibernate Integration Issue Type: Bug Environment: Sun Microsystems Java 1.5, build 22 Weblogic 9.2.4 Reporter: Kirill Linnik Assignee: Steve Ebersole