====== Using Java ======

=====Example Java Script=====

<file java Hello.java>
/*
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
 */
/*
 * Copyright (c) 2011      Cisco Systems, Inc.  All rights reserved.
 *
 */

import mpi.*;
import java.net.InetAddress;
 
class Hello {
    static public void main(String[] args) throws MPIException {
        MPI.Init(args);

        int myrank = MPI.COMM_WORLD.getRank();
        int size = MPI.COMM_WORLD.getSize() ;
        InetAddress IP;
        try {
            IP = InetAddress.getLocalHost().getLocalHost();
            System.out.println("Hello world from rank " + myrank + " of " + size+" I'm running on "+IP.getLocalHost());
        }
            catch (Exception e) {
        }
        MPI.Finalize();
    }
}
</file>

<code bash>
$ module add chpc/openmpi/1.10.3/gcc-5.1.0_java-1.8.0_73
$ mpijavac Hello.java
</code>

<file bash java_test.qsub>
#!/bin/bash
#PBS -l select=2:ncpus=24:mpiprocs=24
#PBS -l walltime=00:01:00
#PBS -q normal
#PBS -P SHORTNAME
#PBS -M YOUREMAILADDRESS
#PBS -m be
#PBS -e /mnt/lustre/users/USERNAME/java_test/std_err.txt
#PBS -o /mnt/lustre/users/USERNAME/java_test/std_out.txt
#PBS -N JAVA_TEST

module add chpc/openmpi/1.10.3/gcc-5.1.0_java-1.8.0_73

NP=`cat ${PBS_NODEFILE} | wc -l`

cd /mnt/lustre/users/USERNAME/java_test
mpirun -np ${NP} -machinefile ${PBS_NODEFILE} java Hello
</file>

<code bash>
$ qsub java_test.qsub
</code>

**Notes:**
  * Replace ''USERNAME'' with **your** user name.
  * Replace ''YOUREMAILADDRESS'' with **your** email address.