sclass AutoVMExit extends TimerTask {
  static boolean installed;
  static boolean disabled;
  int lastObjectCount = -1;
  static java.util.Timer timer;
  static int firstDelay = 30000;
  static int delay = 5000;

  public static void install() {
    if (!installed) {
      installed = true;
      if (!disabled) {
        timer = new java.util.Timer("AutoVMExit");
        timer.scheduleAtFixedRate(new AutoVMExit(), firstDelay, delay);
      }
    }
  }

  /** Looks for objects that give us a reason to keep the VM alive.
   *  Right now we count windows, tray icons and JavaFX stages. */
  public void run() {
    if (isHiddenVM()) ret;
    
    int objectCount = autoVMExit_visibleObjects();

    //System.out.println("Windows: " + objectCount);
    if (objectCount == 0 && lastObjectCount == 0) {
      System.out.println("AutoVMExit: No windows open or tray icons installed - exiting");
      cleanKillVM();
      //System.exit(0);
    }
    lastObjectCount = objectCount;
  }

  public static void disable() {
    disabled = true;
    if (timer != null)
      timer.cancel();
  }

  public static int getFirstDelay() {
    return firstDelay;
  }

  public static void setFirstDelay(int firstDelay) {
    AutoVMExit.firstDelay = firstDelay;
  }

  public static int getDelay() {
    return delay;
  }

  public static void setDelay(int delay) {
    AutoVMExit.delay = delay;
  }
}

Began life as a copy of #1007192