static L<JMenuItem> getMenuItems(JMenu menu) {
  if (menu == null) null;
  ret nonNulls(countIterator(menu.getItemCount(), i -> menu.getItem(i)));
}

// seems we have to emulate this for JPopupMenu
static L<JMenuItem> getMenuItems(JPopupMenu menu) {
  if (menu == null) null;
  ret instancesOf JMenuItem(asList(menu.getSubElements()));
}