Transparent Distributed Java

We describe our modi cations to the Ka e Java runtime to support transparent distribution of Java threads and objects across multiple processors and machines. We also discuss the design of a shared object system used by the Java runtime to provide transparent object sharing to Java applications. Although we also implemented a version for symmetric multiprocessors (SMPs), this paper focuses on a version designed for networks of workstations (NOWs). We describe our experiences and di culties in modifying Ka e, and present some ideas on how to best construct a distributed Java runtime system which includes support for transparent distributed threads and objects. Finally, we present performance results based on micro and application level benchmarks. These results show that a single-threaded Java runtime can be converted into a multi-thread distributed runtime without great loss of performance. The results also however show that the same issues arise with transparency, scalability and performance as in any distributed parallel system.