private static Connection getDBConnection() {
        Connection dbConnection = null;
        url = "jdbc:oracle:thin:@" + server + ":" + port + ":" + sid;
        try {
            Class.forName(driverName);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {
            dbConnection = DriverManager.getConnection(url, username, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return dbConnection;
    }