Hi... I am using 1.4. I infact checked the API documentation, and found that in the tree structure, TreeCache does not implement Serialization. (Its been a while since I coded, so please forgive my ignorance!). When I bind the TreeCache and use it within the app server, it works fine (i.e. I look-it-up it using a servlet). However, if I bind it using a weblogic start up class, but look-it-up in a standalone application, it throws me that exception. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3966946#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...