It's on jboss-serialization.jar, but it should be in jboss-allClient.jar as well. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3974717#3974717 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=3974717