Java Swing+DB

package edu;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
public class Login implements ActionListener {
    JTextField username;
    JPasswordField pass;
    JPanel jp;
    JFrame jeff;
    JLabel l1, l2, l3;
    JButton button;

    Login(){
        try {
            Class.forName("org.mariadb.jdbc.Driver");
            Connection cn = DriverManager.getConnection("jdbc:mariadb://localhost:3306/syit","root","mariadb");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        username = new JTextField(20);
        pass = new JPasswordField(20);
        l1 = new JLabel("Username");
        l2 = new JLabel("Password");
        l3 = new JLabel("");
        button = new JButton("Submit");

        jp = new JPanel();
        jp = new JPanel(new GridLayout(3, 2, 10, 10));
        jp.add(l1);
        jp.add(username);
        jp.add(l2);
        jp.add(pass);
        jp.add(l3);
        jp.add(button);

        jeff = new JFrame();
        jeff.add(jp);
        jeff.pack();
        jeff.setVisible(true);
        }

    public void actionPerformed(ActionEvent e) {

    }

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

}