There should be a public API in RMI that can be used to obtain the remote stub for a remote object and also the remote object given a remote stub (if the stub remote object is local to the machine).

In order to serialize an unserializable object that contains a remote object the remote stub for the object needs to be obtained. This need has been expressed by customers.

Also, the complimentary functionality of obtaining the remote object implementation given a remote stub (if the remote object is local to the caller) would be useful to do some short-circuiting on the server.