老人家的舊書房

package onlyfun.caterpillar;

import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.event.*;

public class ThreadDemo extends JFrame {
 public ThreadDemo() {
  JButton btn = new JButton("按我");
   
  btn.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
    Thread thread1 = new Thread(new Runnable() {
     public void run() {
      Graphics g = getGraphics();
      for(int i = 10; i < 300; i+=10) {
       try {
        Thread.sleep(500);
        g.drawOval(i, 100, 10, 10);
       }
       catch(InterruptedException e) {
        e.printStackTrace();
       }
      }
     }
    });    
  Thread thread2 = new Thread(new Runnable() {
   public void run() {
    Graphics g = getGraphics();
    for(int i = 10; i < 300; i+=10) {
     try {
      Thread.sleep(500);
      g.drawOval(i, 150, 15, 15);
     }
     catch(InterruptedException e) {
      e.printStackTrace();
     }
    }
   }
  }); 
   thread1.start();
   thread2.start();
   }
  });  
  getContentPane().add(btn, BorderLayout.NORTH);
   setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
   setSize(320, 200);
    setVisible(true);
    } 
  
public static void main(String[] alio) { 
 new ThreadDemo();
 }
} 
  
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二次元與三次元的差別！？（大誤）