Swing：元件：JButton 不使用 JPanel

import javax.swing.JButton;
import javax.swing.JFrame;

class Frame7 extends JFrame{
 
 Frame7(){
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setBounds(200,200,450,300);
  setTitle("Swing JFrame 視窗");
 }

}
public class FrameJPanel {

 public static void main(String[] args) {
  Frame7 frame = new Frame7();
  frame.setLayout(null);
  
  JButton button1 = new JButton("button 1");
  button1.setBounds(0,0,100,30);
  frame.add(button1);
  
  JButton button2 = new JButton("button 2");
  button2.setBounds(0,50,100,30);
  frame.add(button2);
  
  JButton button3 = new JButton("button 3");
  button3.setBounds(0,100,100,30);
  frame.add(button3);
  
  frame.setVisible(true);
 }

}

執行結果