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

public class bu extends JFrame implements ActionListener
{
    private  JFrame jf;
    private  JButton jb1;
    private  JButton jb2;
    bu()
    {
        jf=new JFrame();
        jb1=new JButton("jb1");
        jb2=new JButton("jb2");
        jf.setLayout(new FlowLayout());
        jf.setLocation(512,384);
        jf.setBounds(10,10,200,400);
        jb1.addActionListener(this);
        jb2.addActionListener(this);
        add(jb1);
        add(jb2);
        setVisible(true);
    }
    public void actionPerformed(ActionEvent e)
    {
        JButton temp;
        temp=(JButton)e.getSource();
        if(temp==jb1) System.out.println("jb1");
        if(temp==jb2) System.out.println("jb2");
    }
    public static void main(String args[])
    {
        new bu();
    }
}

package com.myapp.struts;

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;

public class Main {

    public static void main(String[] args) {
        new Bu();
    }
}

class Bu extends JFrame implements ActionListener {

    private JButton jb1;
    private JButton jb2;

    public Bu() {
        jb1 = new JButton("jb1");
        jb2 = new JButton("jb2");
        setLayout(new FlowLayout());
        setLocation(512, 384);
        setBounds(10, 10, 200, 400);

        jb1.addActionListener(this);
        jb2.addActionListener(this);
        add(jb1);
        add(jb2);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        JButton temp;
        temp = (JButton) e.getSource();
        if (temp == jb1) {
            System.out.println("jb1");
        }
        if (temp == jb2) {
            System.out.println("jb2");
        }
    }
}

------解决方案--------------------
Do not use javax.swing.JFrame.setLayout() use javax.swing.JFrame.getContentPane().setLayout() instead。

jf.getContentPane().setLayout(new FlowLayout()); 
jf.getContentPane().add(jb1); 
jf.getContentPane().add(jb2);