如何暂停主Swing线程直到Swing计时器结束？

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TimerExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Timer Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);

        JLabel label = new JLabel("Timer will start in 5 seconds...");
        frame.add(label);

        frame.setVisible(true);

        // 创建一个计时器，延迟5秒后触发一次
        Timer timer = new Timer(5000, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                label.setText("Timer has finished!");
            }
        });

        // 启动计时器
        timer.setRepeats(false); // 设置为不重复
        timer.start();

        // 确保主线程等待计时器结束
        try {
            Thread.sleep(5000); // 主线程休眠5秒
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }

        System.out.println("Main thread continues after timer finishes.");
    }
}