A distributed object model for the Java']Java(TM) system

We show a distributed object model for the Java(TM)(1) System [Arnold & Gosling 1996; Gosling et al. 1996] (hereafter referred to simply as ''Java'') that retains as much of the semantics of the Java object model as possible, and only includes differences where they make sense for distributed objects, The distributed object system is simple, in that a) distributed objects are easy to use and to implement, and b) the system itself is easily extensible and maintainable. We have designed such a model and implemented a system that supports remote method invocation (RMI) for distributed objects in Java. This system combines aspects of both the Modula-3 Network Objects system [Birrell et al. 1994] and Spring's subcontract [Hamilton et al. 1993] and includes some novel features. To achieve its goal of seamless integration in the language, the system exploits the use of object serialization (pickling) [Riggs et al. 1996] to transmit arguments and return values, and also exploits unique features of Java in order to dynamically load stub code to clients(2). The system includes distributed reference-counting garbage collection for distributed objects and will include activation [Object Management Group 1991; Wollrath et al. 1995] of object servers in the future.