Performs better: JavaBean. You don't have to serialize/ deserialize the
Java datatypes to xml.
This is alwas the prefered way if you communicate java to java.
If you have a communication between java and e.g. VB than XML might be an option (see WebServices), but consider CORBA too.
XML between java environments might be an option if you really need decouple the service from it's consumers, or if you anyway need to transform it into XML for later XSL transformations.
So no clear answer, it depends on what you intend to do.