JR: flexible distributed programming in an extended Java

Java provides a clean object-oriented programming model and allows for inherently system-independent programs. Unfortunately, Java has a limited concurrency model, providing only threads and remote method invocation (RMI). The JR programming language extends Java to provide a rich concurrency model. JR provides dynamic remote virtual machine creation, dynamic remote object creation, remote method invocation, asynchronous communication, rendezvous, and dynamic process creation. JR programs are written in an extended Java and then translated into standard Java programs. The JR run-time support system is also written in standard Java. This paper describes the JR programming language and its implementation. Some initial measurements of the performance of the implementation are also included.