RMI-IIOP. The RMI-IIOP subsystem is composed of APIs that allow for the use of RMI-style programming that is independent of the underlying protocol, as well as an implementation of these APIs that supports both the J2SE native RMI protocol (JRMP) and the CORBA IIOP protocol. J2EE applications can use RMI-IIOP, with the IIOP protocol support, to access CORBA services that are compatible with the RMI programming restrictions (see the RMI-IIOP spec for details). Such CORBA services would typically be defined by components that live outside of a J2EE product, usually in a legacy system. Only J2EE application clients are required to be able to define their own CORBA services directly, using the RMI-IIOP APIs. Typically such CORBA objects would be used for callbacks when accessing other CORBA objects.
J2EE applications are required to use the RMI-IIOP APIs (specifically the narrow method of javax.rmi.PortableRemoteObject) when accessing Enterprise JavaBeans components, as described in the EJB 1.1 specification. This allows enterprise beans to be protocol independent. However, there is currently no requirement that enterprise beans be accessible using the IIOP protocol. Such a requirement will be added in a future version of this specification. With this requirement, enterprise bean components will appear as CORBA objects.