Hi, I have been working several days with this issue. At last this problem is caused in the Client application. In my case a web app. It was not able to recognize the type that the server was returning (ArrayList in this case). Another important thing, correct me if I am wrong, is that Web Services Soap Messages not support ArrayList directly, so if you would like to use it you must implement an ArrayList by yourself. A pretty hard work. The thing that I have done is to return an Array (suported by the Web Services) of my own objects, that I have mapped previously. My solution was to create a Web Service Client using Eclipse Wtp. It creates a EAR that includes all the necessary stuff for map the user types. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4121230#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...