EJB Statefull does not preserve the state if it is called from different Servlets?

A Stateful EJB:

package ejb;

import javax.ejb.Init;
import javax.ejb.Remove;
import javax.ejb.Stateful;

@Stateful

public class Contador implements ContadorRemote {

    private int cantidad;

    @Init
    public void initialize(){
        cantidad =0;
    }

    @Override
    public void incrementar() {

        this.cantidad = cantidad + 1;

    }

    @Override
    public void setCantidad(int cantidad){
        this.cantidad=cantidad;
    }

    @Override
    public int getCantidad(){
        return this.cantidad;
    }

    @Override
    @Remove
    public void remove(){
        cantidad=0;
    }


}

Its interface:

package ejb;

import javax.ejb.Local;

/**
 *
 * @author etienotb
 */
@Local
public interface ContadorRemote {
    void initialize();
    void incrementar();
    void setCantidad(int cantidad);
    int getCantidad();
    void remove();


}

Two Servlets:

package servlet;

import ejb.ContadorRemote;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.ejb.EJB;
import javax.naming.InitialContext;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author etienotb
 */
@WebServlet(name = "InicializarContadorServlet", urlPatterns = {"/InicializarContadorServlet"})
public class InicializarContadorServlet extends HttpServlet {

    //@EJB(lookup = "java:app/WebApplicationHibernate/Contador!ejb.ContadorRemote")
    @EJB
    ContadorRemote unContador;

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */

            this.unContador.incrementar();
            System.out.println("cantidad inicialiar:" + this.unContador.getCantidad());


        }
    }
}

and

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package servlet;

import ejb.ContadorRemote;
import java.io.IOException;
import java.io.PrintWriter;
import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author etienotb
 */
@WebServlet(name = "ConsultarContadorServlet", urlPatterns = {"/ConsultarContadorServlet"})
public class ConsultarContadorServlet extends HttpServlet {

    //@EJB(lookup = "java:app/WebApplicationHibernate/Contador!ejb.ContadorRemote")
    @EJB
    ContadorRemote unContador;

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            unContador.incrementar();
            System.out.println("cantidad consultar:" + this.unContador.getCantidad());

        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

Supposedly the ejb unContador should share the state for the entire secion, but when executing it it keeps the state but only for calls to the same servlet. How can I make all servlets share the same one Counter?