Coding Java "Simple Login"

Selamat mencoba yah guys :)


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

public class SimpleLogin extends JFrame implements ActionListener {
    private JLabel label1, label2;
    private JTextField txtUser;
    private JPasswordField pwdPass;
    private JButton btnLogin, btnExit;

    public SimpleLogin() {
        super ("Sign in");

        Container container = getContentPane();
        container.setLayout(new FlowLayout());

        label1 = new JLabel ("Username : ");
        label2 = new JLabel ("Password : ");

        txtUser = new JTextField (20);
        txtUser.setToolTipText("Input Username");
        pwdPass = new JPasswordField(20);

        btnLogin = new JButton ("Sign in");
        btnLogin.addActionListener(this);
        btnExit = new JButton ("Exit");
        btnExit.addActionListener(this);

        container.add(label1);
        container.add(txtUser);
        container.add(label2);
        container.add(pwdPass);
        container.add(btnLogin);
        container.add(btnExit);

        setSize (300,200);
        setVisible (true);
    }

    public static void main (String args[]) {
        SimpleLogin test = new SimpleLogin();
        test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private String user = "", pass = "";
    public void actionPerformed (ActionEvent e) {
        if (e.getSource() == btnLogin) {
            user = txtUser.getText();
            pass = pwdPass.getText();
            if (user.equals("praktikan") && pass.equals("praktikan")) {
                JOptionPane.showMessageDialog(null, "Login success");
            } else {
                JOptionPane.showMessageDialog(null, "Username and password dosn't match!");
                txtUser.setText("");
                pwdPass.setText("");
                txtUser.requestFocus(true);
            }
        } else if (e.getSource() == btnExit){
            JOptionPane.showMessageDialog(null,"Thanks and see you later.");
            System.exit(0);
        }
    }
}

Please, coment-nya yah :)