static <A extends JComponent> A jMaxWidth(int w, A c) {
  Dimension size = c.getMaximumSize();
  c.setMaximumSize(new Dimension(w, size.height));
  ret jPreferWidth(w, c); // this helps
}

static <A extends JComponent> A jMaxWidth(A c, int w) {
  ret jMaxWidth(w, c);
}