static JInternalFrame centerInternalFrame(final JInternalFrame f) {
  swing {
    Container c = f.getParent();
    if (c != null) {
      //print("Container type: " + className(c) + ", bounds: " + c.getBounds());
      f.setLocation((c.getWidth()-f.getWidth())/2, (c.getHeight()-f.getHeight())/2);
    }
  }
  ret f;
}

static JInternalFrame centerInternalFrame(final int w, final int h, final JInternalFrame f) {
  swing {
    f.setSize(w, h);
  }
  ret centerInternalFrame(f);
}