Тестовое задание. Контроллер.

package com.game.service;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class DatabaseTester {
    public static void main(String[] args) {

        Connection dbConnection = null;

        try {
            String url = "jdbc:mysql://localhost:3306/rpg?serverTimezone=UTC&characterEncoding=UTF-8";
            Properties info = new Properties();
            info.put("user", "root");
            info.put("password", "root");

            dbConnection = DriverManager.getConnection(url, info);

            if (dbConnection != null) {
                System.out.println("Successfully connected to MySQL database test");
            }

        } catch (SQLException ex) {
            System.out.println("An error occurred while connecting MySQL databse");
            ex.printStackTrace();
        }
    }
}

String url = "jdbc:mysql://localhost:3306/rpg?serverTimezone=UTC&characterEncoding=UTF-8&useSSL=false&enabledTLSProtocols=TLSv1.2";

String url = "jdbc:mysql://localhost:3306/rpg?serverTimezone=UTC&characterEncoding=UTF-8&enabledTLSProtocols=TLSv1.2";

String url = "jdbc:mysql://localhost:3306/rpg?serverTimezone=UTC&characterEncoding=UTF-8&useSSL=false";

перед сдачей на валидацию - ты верни назад оригинальные настройки

com.mysql.cj.exceptions.DataConversionException: Unsupported conversion from DATE to java.lang.Long