package model.db;import java.sql.*;public class Database {  private static final String driver = "com.mysql.jdbc.Driver";  private static final String url = "jdbc:mysql://localhost/store";  private static final String user = "guest";  private static final String password = "";  private static Object driver_obj = null;  private static Connection cx = null;  public static Connection connect() throws Exception {    if (driver_obj == null) {      System.out.println("=> load driver");      driver_obj = Class.forName(driver).newInstance();    }    if (cx == null || cx.isClosed()) {      System.out.println("=> connect");      cx = DriverManager.getConnection(url, user, password);    }    return cx;  }}