Ben, Thanks for you response, that's my careless. now the program works well. And other need to clear. As my understanding, the main distinguish between TreeCache and PojoCache 1. PojoCache only support in-memory(not support passivate to disk or other sources, once passivate, the object will evict out of cache system) while TreeCache support in-memory and passivate to disk or other sources. 2.TreeCache cann't keep object references after state from passivation to activation or replcating from other node while PojoCache can. Any mistakes please correct me, thanks. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3962682#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...