JDM : building distributed synchronization support into Java

The monitor concept has been widely used in a concurrent programming environment for implicitly ensuring mutual exclusion and explicitly achieving process synchronization. It has also been extended to support high-level distributed programming. In this paper, we present JDM, a distributed monitor construct in Java for programming large-scale distributed systems. The distributed monitor construct is based on a well-know tree-based distributed mutual exclusion algorithm proposed by K. Raymond. To increase scalability of the construct, a two-level system architecture is developed, where the node level controls the access to the system-wide shared resources using Raymond's algorithm and the process level synchronizes local processes based on the local monitor concept. An object-oriented design of the system architecture is presented. Implementation and results of performance evaluation are reported and factors that influence the performance of the construct are discussed.