JRadioButtonMenuItemのチェックアイコンを変更する

// com.sun.java.swing.plaf.windows.WindowsIconFactory.java
class RadioButtonMenuItemIcon1 implements Icon, UIResource, Serializable {
  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    AbstractButton b = (AbstractButton) c;
    ButtonModel model = b.getModel();
    if (b.isSelected()) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                          RenderingHints.VALUE_ANTIALIAS_ON);
      g2.fillRoundRect(
          x + 3, y + 3, getIconWidth() - 6, getIconHeight() - 6, 4, 4);
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                          RenderingHints.VALUE_ANTIALIAS_OFF);
      g2.dispose();
    }
  }

  @Override public int getIconWidth()  {
    return 12;
  }

  @Override public int getIconHeight() {
    return 12;
  }
}

class RadioButtonMenuItemIcon2 implements Icon, UIResource, Serializable {
  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    AbstractButton b = (AbstractButton) c;
    ButtonModel model = b.getModel();
    if (b.isSelected()) {
      g.fillOval(x + 2, y + 2, getIconWidth() - 5, getIconHeight() - 5);
    }
  }

  @Override public int getIconWidth()  {
    return 12;
  }

  @Override public int getIconHeight() {
    return 12;
  }
}