public static final String MYSQL_SERVER = "127.0.0.1";

    private static Connection con;

    private static String hostname = MYSQL_SERVER, port = "3306", database = "osrs", user = "root",
            password = "wachtwoord";

    public static final void initialize(String host, String port, String database, String user, String password) {
        MySQL.hostname = host;
        MySQL.port = port;
        MySQL.database = database;
        MySQL.user = user;
        MySQL.password = password;
    }

    public static synchronized void openConnection() throws SQLException, ClassNotFoundException {
        closeConnection();// make sure the connection is not already open
        Class.forName("com.mysql.cj.jdbc.Driver");
        System.out.println("Opening mysql con");
        DriverManager.setLoginTimeout(15000);
        con = DriverManager.getConnection(
                "jdbc:mysql://" + MySQL.hostname + ":" + MySQL.port + "/" + MySQL.database + "?allowMultiQueries=true",
                MySQL.user, MySQL.password);
        con.prepareStatement("USE " + database).execute();
    }

    public static synchronized void closeConnection() {
        try {
            if (con != null && !con.isClosed())
                con.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static synchronized void checkConnection() {
        try {
            if (con == null || !con.isValid(0))
                openConnection();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }