2.5 Type Equivalency of Remote Objects with Local Stub

In the distributed object model, clients interact with stub (surrogate) objects that have exactly the same set of remote interfaces defined by the remote object's class; the stub class does not include the nonremote portions of the class hierarchy that constitutes the object's type graph. This is because the stub class is generated from the most refined implementation class that implements one or more remote interfaces. For example, if C extends B and B extends A, but only B implements a remote interface, then a stub is generated from B, not C.

Because the stub implements the same set of remote interfaces as the remote object's class, the stub has, from the point of view of the Java system, the same type as the remote portions of the server object's type graph. A client, therefore, can make use of the built-in Java operations to check a remote object's type and to cast from one remote interface to another.

Stubs are generated using the rmic compiler.