ok ... My code just doesn't work then and I have no idea why. As a test I used twiddle to print out the mbean info into an xml file. Then I copied the persistent descriptor section from the JBoss persistent example sar directory into this same file. I changed my code to read this XML file in instead, as follows: work.MyClass mBean = new work.MyClass(); ObjectName objectName = new ObjectName("mydomain.com:job=MyJob,id=" + System.identityHashCode(mBean)); XMBean mmb = new XMBean(mBean, "http://myhost.com/mbean.xml"); server.registerMBean(mmb, objectName); and ... the persistence worked!!!! Of course, it now means I have to maintain the descriptor as well as the code, which I shouldn't need to, but it allows me to move onto the next problem at least (and a new post/topic). View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982580#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...