What is the difference between CORBA-IIOP, RMI-IIOP, RMI-JRMP? My understanding in Short CORBA-IIOP: PLatform and language independent technology for distrbuted communication mechanism/protocol. RMI-IIOP: Java implementation of CORBA-IIOP that abides by the Java RMI API. RMI-JRMP: Pure Java implementation of RMI API for distributed communication. Then what about CORBA IDL and Java IDL? Same as IIOP, just to be replaced with Interface Definition Language? I am expecting some good wordings and short briefs, if possible.