Head First EJB

How EJB uses RMI

In EJB, a client’s entry point into the enterprise application is nearly always through a reference (stub) to a Remote object. Yes, it is possible, and sometimes necessary, to use a local client (i.e. a client in the same heap as the bean, and which doesn’t use RMI to invoke business methods), but this is for only a few very special cases.

So RMI lies at the heart of most client-to-bean communication. But as you saw a hint of in the first chapter, the EJB architecture is a little more complex than a simple client-to-stub-to-Remote-object scenario. In EJB, the bean—the thing on which the client wants to call business methods—is not Remote!

Plain RMI

RMI in EJB