static void blinkWindowUsingSize(JWindow w) {
  blinkWindowUsingSize(w, -1);
}

static void blinkWindowUsingSize(final JWindow w, final int howOften) {
  final Dimension size = w.getSize();
  awtEvery(w, 1000, new Runnable {
    bool on = true;
    int n = howOften*2;
    
    public void run() {
      w.setSize((on = !on) ? size : new Dimension(0, 0));
      if (howOften > 0 && --n <= 1)
        w.dispose();
    }
  });
}

Began life as a copy of #1013344