This is just a open question, don't know if this is the right place to ask this.?
Q: How feasible it is to implement MapReduce Job using RMI or CORBA?
i) What is MapReduce : http://en.wikipedia.org/wiki/MapReduce
Feasible but pointless I would say. As the Wikipaedia article says, I/O is typically via a distributed file system, which would give you restarting, recovery, fault-tolerance, etc. RPC mechanisms don't do that.