I was asked the same question in a job interview last week. This company is developing some projects with RMI. RMI, EJB, CORBA, C++ are used there. But I really don't know how they use RMI with EJB, CORBA together. Perhaps they use RMI in a single project development. I just answered this question with "EJB is based on RMI, but EJB is more complex than RMI." I should have told them "I had ever developed project with EJB so I can start to write codes with RMI in half a hour", but I forgot to mention it. Maybe I can't get that job offer.