certainly its possible, jBPM is a business process engine, and you can communicate to it using your application. As I mentioned in another thread http://www.jboss.com/index.html?module=bb&op=viewtopic&t=81129 , JBoss SEAM can help with this kind of use case as well. Here is a link to the SEAM documentation referring to jBPM: http://docs.jboss.com/seam/reference/en/html/tutorial.html#todo
i looked to the post,
in my case, we want that the jbpm engine deals with the process states and let the business part developped by the j2ee application.
for exemple, can i, upon the actions, invoke some services in the business layer of the j2ee application.
i think that could be done.
Yes, that is exactly how jBPM works. The jBPM engine manages the process state, and will call to your J2EE application logic through actions that you setup.