为啥不能运行里

package ch01;

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.WindowConstants;

public class Login extends JFrame{
private JLabel userLabel;
private JLabel passLabel;
private JButton exit;
private JButton login;
private Main window;
private Component userPasswordField;
private static TbUserlist user;
public Login(){
setTitle("超市管理系统");
final JPanel panel = new LoginPanel();
panel.setLayout(null);
getContentPane().add(panel);
setBounds(300,200,panel.getWidth(),panel.getHeight());
userLabel = new JLabel();
userLabel.setText("用户名：");
userLabel.setBounds(140,160,200,18);
panel.add(userLabel);
final JTextField userName = new JTextField();
userName.setBounds(190,160,200,18);
panel.add(userName);
passLabel = new JLabel();
passLabel.setText("密码：");
passLabel.setBounds(140,200,200,18);
panel.add(passLabel);
final JPasswordField userPassword = new JPasswordField();
userPasswordField.addKeyListener(new KeyAdapter(){
public void keyPressed(final KeyEvent e){
if(e.getKeyCode()==10)
login.doClick();
}
});
userPassword.setBounds(190,200,200,18);
panel.add(userPassword);
login = new JButton();
login.addActionListener(new ActionListener(){
@SuppressWarnings("deprecation")
public void actionPerformed(final ActionEvent e){
user = Dao.getUser1(userName.getText(),userPassword.getText());
if(user.getUsername1()==null||user.getUsername()==null){
userName.setText(null);
userPassword.setText(null);
return;
}
setVisible(false);
window = new Main();
((Component) window.frame).setVisible(true);
}
});
login.setText("登录：");
login.setBounds(200,250,60,18);
panel.add(login);
exit = new JButton();
exit.addActionListener(new ActionListener(){
public void actionPerformed(final ActionEvent e){
System.exit(0);
}
});
exit.setText("退出：");
exit.setBounds(280,250,60,18);
panel.add(exit);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
}
public static TbUserlist getUser(){
return user;
}
public static void setUser(TbUserlist user){
Login.user = user;
}


private static final long serialVersionUID = 1L;

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

}

}