first time i do this

DatabaseUtil.java

package sample.server.mysql;

import sample.server.serverplayer.DataPlayer;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * Created by @Ikeetjeop aka Nick on 30-Jun-18.
 */
public class DatabaseUtil {
    
    
    /*
    Before you gonna check i want you to know this;
    
    dataPlayers is going in another class;
    
    And later i gonna add json so not everything has to store in the memory xD
    
    Feels free to use it also lol :p
    
     */
    private List<DataPlayer> dataPlayers = new ArrayList<>();
    
    
    private Connection connection = null;
    private PreparedStatement ptmt = null;
    private ResultSet resultSet = null;

    public Connection getConnection() {
        Connection conn;
        conn = ConnectionFactory.getInstance().getConnection();
        return conn;
    }

    public void addNewPlayer(DataPlayer dataPlayer) {
        try {
            String queryString = "INSERT INTO playerdata(UUID, SessionID, NickName, Password, wins, loses) VALUES(?,?,?,?,?,?)";
            connection = getConnection();
            ptmt = connection.prepareStatement(queryString);
            ptmt.setString(1, dataPlayer.getNickName());
            ptmt.setString(2, dataPlayer.getSessionID());
            ptmt.setString(3, dataPlayer.getNickName());
            ptmt.setString(4, dataPlayer.getPassWord());
            ptmt.setInt(5, dataPlayer.getWins());
            ptmt.setInt(6, dataPlayer.getLoses());
            ptmt.executeUpdate();
            dataPlayers.add(new DataPlayer(dataPlayer.getUuid(), dataPlayer.getSessionID(), dataPlayer.getNickName(), dataPlayer.getPassWord(), dataPlayer.getWins(), dataPlayer.getLoses()));
            System.out.println("Data Added Successfully");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeMysqlConnection();
        }

    }

    public void update(DataPlayer dataPlayer) {
        try {
            String queryString = "UPDATE playerdata set NickName=?, SessionID=?, NickName=?, Password=? where UUID";
            connection = getConnection();
            ptmt = connection.prepareStatement(queryString);
            ptmt.setString(1, dataPlayer.getNickName());
            ptmt.setString(2, dataPlayer.getSessionID());
            ptmt.setString(3, dataPlayer.getPassWord());
            ptmt.setString(4, dataPlayer.getUuid().toString());
            ptmt.executeUpdate();
            System.out.println("Table Updated Successfully");
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeMysqlConnection();
        }
    }

    public void importBackFromMysql() {
        try {
            String queryString = "SELECT * FROM players";
            connection = getConnection();
            ptmt = connection.prepareStatement(queryString);
            resultSet = ptmt.executeQuery();
            List<DataPlayer> dataPlayerList = new ArrayList<>();
            while (resultSet.next()) {
                dataPlayerList.add(new DataPlayer(
                        UUID.fromString(resultSet.getString("UUID")),
                        resultSet.getString("SessionID"),
                        resultSet.getString("NickName"),
                        resultSet.getString("Password"),
                        resultSet.getInt("Wins"),
                        resultSet.getInt("Loses")));
            }
            dataPlayers = dataPlayerList;
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeMysqlConnection();
        }
    }

    public void importBackByUUID(UUID uuid) {
        try {
            connection = getConnection();
            ptmt = connection.prepareStatement("SELECT * FROM players WHERE UUID='" + uuid + "'");
            resultSet = ptmt.executeQuery();
            List<DataPlayer> dataPlayerList = new ArrayList<>();
            if (resultSet.next()) {
                dataPlayerList.add(new DataPlayer(
                        UUID.fromString(resultSet.getString("UUID")),
                        resultSet.getString("SessionID"),
                        resultSet.getString("NickName"),
                        resultSet.getString("Password"),
                        resultSet.getInt("Wins"),
                        resultSet.getInt("Loses")));
            }
            dataPlayers = dataPlayerList;
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeMysqlConnection();
        }
    }


    private void closeMysqlConnection(){
        try {
            if (resultSet != null)
                resultSet.close();
            if (ptmt != null)
                ptmt.close();
            if (connection != null)
                connection.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}