添加和删​​除 JLabel 上的图标

您好，我有一个标签，我已为其设置了图标，我想在单击按钮后删除此图标，它的方法是什么？

// Create icon
Icon icon = new ImageIcon(getClass().getResource("/foo/bar/baz.png"));

// Create label
final JLabel lbl = new JLabel("Hello, World", icon, JLabel.LEFT_ALIGNMENT);

// Create button
JButton btn = new JButton("Click Me");
btn.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent evt) {
    // Remove icon when button is clicked.
    lbl.setIcon(null);

    // **IMPORTANT** to call revalidate() to cause JLabel to resize and be repainted.
    lbl.revalidate();
  }
});