JAVA语言编写1个事件处理图象用户界面

我写了一个登录的dialog代码 有登陆和关闭 输入用户名:Admin和密码123后 提示可以进入主页面 下面是源代码

import javax.swing.JDialog;
import java.awt.Dimension;
import java.awt.Toolkit;

import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.Rectangle;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
import javax.swing.JPasswordField;

public class LoginDialog extends JDialog {

private JPanel jPanel = null;

private JButton loginButton = null;

private JButton clolseButton = null;

private JLabel usernameLabel = null;

private JLabel passwordLabel = null;

private JTextField usernameField = null;

private JPasswordField passwordField = null;

/**
* This method initializes
*
*/
public LoginDialog()