Your question is pretty vague. But here is a possible scenario:
o Client program must access (remotely) 10 different object classes.
o The object classes are related. That is, one class can logically be requested from another class. In all, the classes to be accessed can be arranged in a tree.
o Alternatively: All classes can be accessed from some kind of a "login" class, or "entry" class.
So the login or entry or top-level class is designed to be registered with RMI. When the client gets a reference to that object, the client can then ask for - remote - references to the other objects. (The other objects are all UnicastRemoteObjects, but are not registered with the RmiRegistry.)