I have re-deployed all hibernate related jars. Now I get the following error: 23.10.09 14:32:37 FATAL [s.OptimisticLockingInterceptor: 55] No transaction manager lookup class has been defined. Transactions cannot be used and thus OPTIMISTIC locking cannot be used! Expect errors!! (main) 23.10.09 14:32:37 FATAL [s.OptimisticLockingInterceptor: 55] No transaction manager lookup class has been defined. Transactions cannot be used and thus OPTIMISTIC locking cannot be used! Expect errors!! (main) Relevant part of config: <prop key="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.JOTMTransactionManagerLookup</prop> | JOTMTransactionManagerLookup.class is in $CLASSPATH Matches in /usr/local/opt/tomcat/webapps/Joca-JCL-Handler/WEB-INF/lib/hibernate-core-3.3.2.GA.jar: | 1625 Wed Jun 24 01:55:44 CEST 2009 org/hibernate/transaction/JOTMTransactionManagerLookup.class View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4261855#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...