Java Distributed Computing

RMI vs. CORBA

In this chapter we’ve implemented the simple distributed compute engine using both CORBA and RMI, and we’ve seen many similarities between the two in terms of functionality. There are also some critical differences between the two technologies. In order for you to understand which distributed object scheme is right for whatever system you’re facing, it’s important to spell out these differences.

The Language Barrier: Advantage or Disadvantage?

As we mentioned before, RMI is a Java-centric distributed object system. The only way currently to integrate code written in other languages into a RMI system is to use the Java native-code interface to link a remote object implementation in Java to C or C++ code. This is a possibility, but definitely not something for the faint of heart. The native-code interface in Java is complicated, and can quickly lead to fragile or difficult-to-maintain code. CORBA, on the other hand, is designed to be language-independent. Object interfaces are specified in a language that is independent of the actual implementation language. This interface description can then be compiled into whatever implementation language suits the job and the environment.

This distinction is really at the heart of the split between the two technologies. RMI, as a Java-centric system, inherits all of the benefits of Java. An RMI system is immediately cross-platform; any subsystem of the distributed system can be relocated to any host that has a Java virtual machine ...