Regarding the class loading behaviour of different versions of the app server, I recommend posting on the app server user forums. Regarding dependencies of JBoss Cache, you'd need: concurrent.jar commons-logging.jar jgroups.jar jboss-serialization.jar jboss-system.jar jboss-minimal.jar jboss-common.jar trove.jar That is, unfortunately, the bare minimum (for JBC 1.x) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4069657#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...