If the existing CORBA object has its remote interfaces defined originally in CORBA IDL, then interoperability is not possible. RMI-IIOP applications can interoperate with other CORBA objects only when their remote interfaces are originally defined as Java RMI interfaces.

For example, to interoperate between an RMI-IIOP client and a C++ object you need to:

1. Define the remote interface of the object in Java as an RMI interface.

2. Run rmic -iiop against the interface to produce the stub for your RMI-IIOP client.

3. Run rmic -idl against the interface to produce IDL compatible with the RMI interface.

4. Run a C++ stub compiler against the IDL file to produce the C++ skeleton for your C++ server object.