Currently there is a growing interest in using Java for high performance computing. Java has many advantages for high performance computing: it is based on a high-level and object-oriented programming model with support for multithreading and distributed computing. Furthermore, Java?s virtual machine allows applications to run on multiple heterogeneous platforms. A major problem with the use of Java for high performance computing is the I/O. This problem has been solved traditionally in clusters using parallel file systems and parallel I/O libraries, however there is a lack of parallel file systems for Java applications. In this paper, we present a Java parallel I/O library called jExpand. It provices high performance I/O by using several NFS servers in parallel, as NFS can be found in multiple platforms (Linux, Solaris, Windows 2000, etc), we provide a universal parallel file system that can be used everywhere. jExpand requires no changes in the NFS server as it uses RPC operations to provide parallel access to the same file. The paper describes the design, implementation and evaluation of jExpand.