RMI public APIs that use RemoteStub as a parameter or return value should
be changed to use the type java.rmi.Remote instead. The use of RemoteStub
provides less flexiblity in future RMI implementations. The return values
of the following methods need to be changed:

RemoteObject.toStub
UnicastRemoteObject.exportObject (the new one in 1.2)
Activatable.exportObject
Activatable.register