MySql database connection with Jakarta ee via JPA and Wildfly

Question

i've been developping an app for a uni project and i started with 3 simple tables (Student, Teacher and Subject), but when i try to list all the subject in the Controller servlet it shows an error on the web

this is the code for my controller

package mvcController;


import mvcModel.*;


import jakarta.ejb.EJB;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import mvcModel.SubjectService;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import entities.Subject;

/**
 * Servlet implementation class Controller
 */
public class Controller extends HttpServlet {
    private static final long serialVersionUID = 1L;
    
    @EJB 
    private SubjectService subjectService; 
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Controller() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
        List<Subject> subjects = new ArrayList<Subject>(); 
        subjects = subjectService.getAllSubjects(); 
        for(Subject sub : subjects) 
        response.getWriter().append(sub.getSubjectTitle()+"\n"); 
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

and this is my perisstence.xml file

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
    <persistence-unit name="tp2jee" transaction-type="JTA">
        <jta-data-source>java:/MysqlXADS</jta-data-source>
    </persistence-unit>
</persistence>

Notes to consider:

1. every entity has the @Entity annotation
2. Mysql database created and has the 3 tables and data (verified with select *)

Thank you in advance