I have deployed a simple service in ESB. It have a client stub and a server stub. Normally the client sends messages synchronously to the server, and then, the server replies. But in some cases, the server needs to send some messages asynchronously. Can I do this? I suppose that I can, but I don't know the issues of doing it. How can I process this messages in the client side?
It can certainly be done but it would depend on your requirements as to how you would approach it.
You may find that http://www.jboss.org/community/docs/DOC-9105 gives you some ideas on how to handle the communications.