static public void main( String args[] ) throws Exception {
    // Get file channel
    RandomAccessFile raf = new RandomAccessFile( "usefilelocks.txt", "rw" );
    FileChannel fc = raf.getChannel();

    // Get lock
    System.out.println( "trying to get lock" );
    FileLock lock = fc.lock( start, end, false );
    System.out.println( "got lock!" );

    // Pause
    System.out.println( "pausing" );
    try { Thread.sleep( 3000 ); } catch( InterruptedException ie ) {}

    // Release lock
    System.out.println( "going to release lock" );
    lock.release();
    System.out.println( "released lock" );

    raf.close();
  }