谁能知道这段代码的运行结果？
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PasswordDialog extends JDialog implements ActionListener {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    
    public JTextField tfUser;//用来输入账号
    public JPasswordField pfPwd;//用来输入密码
    private JButton btOK,btCancel;
    public boolean cancel;//是否取消输入
    
    public PasswordDialog(Frame owner){//构造函数
        super(owner,"请输入账号密码",true);//独占式对话框
        Container content = getContentPane();
        content.setLayout(new BorderLayout());
        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridLayout(2,2,0,10));
        panel1.add(new JLabel("账号："),JLabel.CENTER);
        panel1.add(tfUser = new JTextField(10));
        panel1.add(new JLabel("密码："),JLabel.CENTER);
        panel1.add(pfPwd = new JPasswordField(10));
        JPanel panel2 = new JPanel();
        panel2.add(btOK = new JButton("确定"));
        panel2.add(btCancel = new JButton("取消"));
        btOK.addActionListener(this);
        btCancel.addActionListener(this);
        content.add(panel1,BorderLayout.CENTER);
        content.add(panel2,BorderLayout.SOUTH);
        setSize(300,200);
    }
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        //实现ActionListener
        cancel = e.getSource()==btCancel;//是否按下"取消"按钮
        setVisible(false);//关闭对话框    
    }
}