static JButton jbutton(S text, Runnable action) {
  ret newButton(text, action);
}

static JButton jbutton(S text, O action) {
  ret newButton(text, action);
}

// button without action
static JButton jbutton(S text) {
  ret newButton(text, null);
}

/*static JButton jbutton(BufferedImage img, O action) {
  ret setButtonImage(img, jbutton("", action));
}*/

static JButton jbutton(Action action) {
  ret swingNu(JButton.class, action);
}