What are smart proxies?

A smart proxy is a class, instantiated in the client VM, that holds onto a remote object reference. It implements the object's remote interface and typically forwards most of the calls on the interface to the remote object, just like an RMI stub. However, a smart proxy is more useful than the RMI stub in that you can change the behavior of the remote interface to do more than forward calls to the remote object. For instance, a smart proxy can locally cache state from the remote object to avoid the network overhead on every method call.

For more details, see the excellent Javaworld article by Jeff Wilson, Get smart with proxies and RMI