System development using Java and distributed object technology (DOT) is becoming common, and can become the standard way of doing network computing in the near future. The performance of DOTs is crucial in high-performance network computing systems. In this paper, the performance of popular DOTs for Java is evaluated in a common environment employing the fastest available PCs and 100 Mbit/s Ethernet. We evaluate HORB, Java RMI, Voyager, two commercial CORBA IIOP implementations, and Distributed COM. For comparison a Java socket version and a C socket version are also evaluated. To represent the characteristics of the DOT, the performance of primitive object operations including remote object creation, remote method call, transferring arrays of objects and transferring large numerical data is measured and evaluated. No DOT won all benchmarks, but HORB showed very good performance for most benchmarks. © 1998 John Wiley & Sons, Ltd.

Protocol synthesis is used to derive a protocol specification based on a service specification. In the previous protocol synthesis methods, if the service specification includes simultaneous transmission of primitives, then the derived protocol specification includes protocol errors of unspecified receptions caused by message collisions. This paper extends a class of derived protocol specifications to include message collisions which often happen in real communication protocols, and proposes a protocol synthesis method such that (1) simultaneous transmission of primitives causing message collisions can be described in the service specifications, and (2) transitions for avoiding protocol errors of unspecified receptions can be generated by new transition synthesis rates. This paper also proposes a verification method for determining a real-time bound in the synthesized protocol specification using the task scheduling algorithm for multiprocessor systems.>