Servlet JPA problem

hi guys
I developed my Entities and use JPA for connect to DBs
alright I have a problem

I developed a Servlet that shown all of the records from test table
it's work good except first time
for first time glassfish return

" Exception [EclipseLink-8034] (Eclipse Persistence Services - 1.0.1 (Build 20080905)): org.eclipse.persistence.exceptions.JPQLException Exception Description: Error compiling the query [all: select t from test t]. Unknown abstract schema type [test]. "

bty;this servlet uses of JPQL

and this return error just for 1st time

and i don't have any problem with adding or removing datas

an the servlet

package Servlets.dbConnections.JPALinks.test2Table;

import JPAs.test2Table;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author ArAsh
 */
public class test2Show extends HttpServlet {

@PersistenceUnit(unitName="JPA")
    private EntityManagerFactory EMF;
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {EntityManager EM=EMF.createEntityManager();
            List<test2Table> res=EM.createQuery("select t2 from test2Table t2").getResultList();
            out.println("<html>");
            out.println("<head><link rel=\"stylesheet\" type=\"text/css\" href=\""+request.getContextPath()+"/Statics/public.css\"/>");
            out.println("<title>Servlet test2Show</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<span>test2 table records</span><table><tr><td>ID</td><td>refID</td><td>tvalue</td></tr>");int s=0;
            for(test2Table t2:res){out.print("<tr class=\""+((s%2==0)?"odd":"even")+"\"><td>"+t2.getId()+"</td><td>"+t2.getT1().getId()+"</td><td>"+t2.getTvalue()+"</td></tr>");s++;}
            out.println("</table></body>");
            out.println("</html>");EM.close();
        } catch(Exception err){out.print(err.toString());}
        finally {
            out.close();
        }
    }

@Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {doGet(request, response);}

@Override
    public String getServletInfo() {
        return "Short description";
    }
}

respect developers