For an effective Internet-based distributed parallel computing platform, Java-Internet Computing Environment (JICE) is designed and implemented with multithreading and remote method invocation mechanisms provided in Java. Specifically, JICE supports a shared memory system model for communication between any two nodes. Under the JICE, communication time is a major candidate of performance bottleneck. To reduce this communication overhead, a method of grouping is designed based on the optimal communication time. Communication performance given by grouping is evaluated through the analysis of execution time and verified via experiments. The results show that communication time can be reduced about 80% from executing some Java benchmarks on JICE.