RMI can be used to write distributed programs in Java. Clients, remote interfaces and servers are written completely in Java and there is no need to learn a separate interface definition language.

IIOP is CORBA’s communication protocol that defines the way bits are sent over a wire between CORBA clients and servers. Interfaces to remote objects are described in a platform-neutral interface definition language (IDL). Mappings from IDL to specific programming languages are implemented, binding the language to CORBA/IIOP.

RMI/IIOP places some restrictions on RMI which enables RMI server objects to use the IIOP protocol and communicate with CORBA client objects written in any language. Thus RMI-IIOP combines RMI ease of use with CORBA cross language interoperability. The entire coding is done in Java language and rmic compiler is used to generate the code necessary for connecting the application via IIOP protocol to others written in any other CORBA compliant language.