如何让JComponents背景变得透明？

import javax.swing.*;
import java.awt.*;

public class TransparentBackgroundExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Transparent Background Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 300);

        JPanel panel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                g.setColor(new Color(0, 0, 0, 0));
                g.fillRect(0, 0, getWidth(), getHeight());
            }
        };
        panel.setOpaque(false);

        JButton button = new JButton("Transparent Button");
        button.setOpaque(false);

        panel.add(button);
        frame.add(panel);
        frame.setVisible(true);
    }
}