Java Swing - 如何设置JCheckBox的按下图标

import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JCheckBox;

public class Main {
  public static void main(String[] argv) throws Exception {

    JCheckBox checkbox = new JCheckBox();

    Icon pressedIcon = new ImageIcon("pres-icon.gif");
    checkbox.setPressedIcon(pressedIcon);

  }
}