We migrated a few days ago from JBoss 5.0.1 to 5.1.0 and are seeing various issues with class loaders. For ex: We see a class cast exception even for a Hibernate Class even though the hibernate libraries are in the lib directory. Another thing we noticed was that all the sar files under the deploy directory is having its own class loader (which was not the case until 5.1.0). Multiple sar files under deploy had the same class loaders, unless specified by the loader-repository in the jboss-service.xml. This seems to be different now. The Question is: How do we keep all the sar files in the same class loader without specifying loader-repository in jboss-service.xml? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4260659#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...