Remote procedure calls and Java Remote Method Invocation

Abstract

Remote procedure call systems have been around since around 1984 when they were first proposed (A.D. Birrell and B.J. Nelson, 1984). During the intervening 15 years, numerous evolutionary improvements have occurred in the basic RPC system, leading to improved systems-such as NCS (T.H. Dineen et al., 1987)-that offer programmers more functionality or greater simplicity. The Common Object Request Broker Architecture from the Object Management Group and Microsoft's Distributed Common Object Model are this evolutionary process's latest outgrowths. With the introduction of Java Developer's Kit release 1.1, a third alternative for creating distributed applications has emerged. The Java Remote Method Invocation system has many of the same features of other RPC systems, letting an object running in one Java virtual machine make a method call on an object running in another, perhaps on a different physical machine. On the surface, the RMI system is just another RPC mechanism, much like Corba and DCOM. But on closer inspection, RMI represents a very different evolutionary progression, one that results in a system that differs not just in detail but in the very set of assumptions made about the distributed systems in which it operates. These differences lead to differences in the programming model, capabilities, and the way the mechanisms interact with the code that implements and built the distributed systems.