Parallel computations in Java with PCJ library

In this paper we present PCJ — a new library for parallel computations in Java inspired by the partitioned global address space approach. We present design details together with the examples of usage for basic operations such as a point-point communication, synchronization or broadcast. The PCJ library is easy to use and allows for a fast development of the parallel programs. It allows to develop distributed applications in easy way, hiding communication details which allows user to focus on the implementation of the algorithm rather than on network or threads programming. The objects and variables are local to the program threads however some variables can be marked shared which allows to access them from different nodes. For shared variables PCJ offers one-sided communication which allows for easy access to the data stored at the different nodes. The parallel programs developed with PCJ can be run on the distributed systems with different Java VM running on the nodes. In the paper we present evaluation of the performance of the PCJ communication on the state of art hardware. The results are compared with the native MPI implementation showing good performance and scalability of the PCJ.