A quick note about using the marshaller vs. locating your classes as Jason's suggested: If you follow the approach Jason outlined, you can leave your objects in the cache instance in that VM. When you redeploy your webapp, it will be able to access those existing objects, with no problem. With the marshaller, if you look at the example I mentioned you'll see it calls inactivateRegion() when you stop the webapp. That's the key thing. That call basically empties the local cache -- no objects left behind whose classes were loaded by the old classloader. When you deploy the webapp again, activateRegion() gets called, which will trigger a state transfer from another node in the cluster. When the transfer occurs, as part of deserializing the transferred objects, the required classes will be loaded from the new classloader. That state transfer is a more complex process than simply using objects that are already cached locally. It also won't work if you simultaneously redeploy the webapp on all nodes in the cluster -- no one will have state to transfer if you do that! View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4093837#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...