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trying to call an ejb from a servlet-client

Posted on 2002-04-15
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Last Modified: 2013-12-10
sir,

I am just a biginner in weblogic and I am facing a problem here and I think you will provide a nice solution to me .
Environment : J2EE/weblogic 5.1/ejb1.1/servlets/win'2000

I have successfuly deployed a stateless session bean named as "Game" and the jndi name used is "gum" at Weblogic 5.1.
Elements inside the "Game.jar" are :
remote interface-> Game.class
home interface  -> GameHome.class
bean class      -> GameBean.class
xml DD          -> META-INF/ejb-jar.xml

I have maintained the dir. structure as follows :  WEB-INF/lib /Game.jar
WEB-INF/classes/toy/*.class
WEB-INF/classes/toy/META-INF/ejb-jar.xml
and using a client servlet class "GameServ.class"
WEB-INF/classes/toy/GameServ.class

Now till I think everything is all right...
Now i started the weblogic...then called the index page
and from the index page I am calling the bean using the mentioned servlet client "GameServ.class" and during calling process i am getting a exception "java.lang.ClassCastException" at the line mentioned below inside ClentServ.class..>
line of error-->"GameHome sh=(GameHome) PortableRemoteObject.narrow(ref,GameHome.class);"

I tried my best but i could not get out of this problem and for more clearity i am writing the java files inside a package "toy" used here..as below....>>

*******************  files used *****************

***** remote interface *******

package toy;

import java.rmi.*;
import javax.ejb.*;
public interface Game extends EJBObject
 {
    public String getName()throws RemoteException;
      public int getSum(int x1,int x2) throws RemoteException;

}

********** home interface *********

package toy;

import java.rmi.*;
import javax.ejb.*;
import java.util.*;

public interface GameHome extends EJBHome
{

   public Game create()throws RemoteException,CreateException;

  }

******** bean **********

package toy;

import javax.ejb.CreateException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import javax.naming.InitialContext;
import javax.sql.DataSource;
import javax.naming.NamingException;
import javax.ejb.EJBException;
import java.sql.*;

  public class GameBean implements SessionBean
  {
   
  public void ejbActivate() {System.out.println("Activate");  }
  public void ejbRemove() {  System.out.println("remove");}
  public void ejbPassivate() { System.out.println("<.....passivate....>"); }
  public void setSessionContext(SessionContext ctx) {    System.out.println("<....sessioncontext....>");    }
  public void ejbCreate () throws CreateException {  System.out.println("<.....create....>");    }
 
  public String getName()
  {
     System.out.println("<.....chk 1 .....>");
       String name="GAME";
      
      return name;
 }

 public int getSum(int x1,int x2)
 {
  int x;
  x=x1+x2;
  System.out.println("<.....chk 5 ...x..> "+x);
  return x;
}

}



**************** ejb-jar.xml **************

<?xml version="1.0"?>

<!DOCTYPE ejb-jar PUBLIC '-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 1.1//EN' 'http://java.sun.com/j2ee/dtds/ejb-jar_1_1.dtd'>

<ejb-jar>
 <enterprise-beans>
  <session>
  <ejb-name>Game</ejb-name>
  <home>toy.GameHome</home>
  <remote>toy.Game</remote>
  <ejb-class>toy.GameBean</ejb-class>
  <session-type>Stateless</session-type>
  <transaction-type>Container</transaction-type>
  </session>
 </enterprise-beans>
</ejb-jar>


**************  clent servlet  ***************


package toy;

import toy.Game;
import toy.GameHome;

import javax.ejb.*;
import javax.rmi.*;
import javax.rmi.PortableRemoteObject;
import javax.naming.InitialContext;
import javax.naming.Context;
import javax.naming.*;
import java.io.*;
import java.util.Properties;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class GameServ extends HttpServlet {

  public void init(ServletConfig config) throws ServletException  {
    super.init(config);
 
  }

  public void service(HttpServletRequest req, HttpServletResponse res)
       throws IOException
  {
 
    res.setContentType("text/html");
    PrintWriter out = res.getWriter();
     
       int ss=0;
       String name="";
       System.out.println("inside client : GameServ ");
       try
       {
          String url = "t3://localhost:7001";
         
        Properties h = new Properties();
          h.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
          h.put(Context.PROVIDER_URL, url);
          Context ctx = new InitialContext(h);
             
        Object ref = ctx.lookup("gum");
        System.out.println("inside client : objref-3 "+ref);
      
        System.out.println("....inside Zone...");

(**)        GameHome sh=(GameHome) PortableRemoteObject.narrow(ref,GameHome.class);
//here i am getting    >> ClassCastEXCEPTION<<

          System.out.println("inside client : sh-4 "+sh);
      
         Game sr =sh.create();
        System.out.println("inside client : sr-5 "+sr);
            
        name=sr.getName();
          System.out.println(" Client ...Got the name : "+name);
 
         ss = sr.getSum(1,7);
         System.out.println("Got the Sum :" + String.valueOf(ss));

      }
      catch(Exception e)
          {
              System.out.println(e);
            }

   
    out.println("<html><head>\n" +
                "<title>Check Servlet</title>\n" +
                "</head>\n" +
                "<body bgcolor=#ffffff> <font face=\"Comic Sans MS\" size+=4 color=red>" +
                "<br> <center><h1> name = "+name+"</h1></center>" +
            "<br> <center><h1> sum = "+ss+"</h1></center>" +
              "<center><h1>Game</h1></center>");
    out.println("</body></html>");
  }
}



************************** Exception I am getting  ****************************

inside the "toy.GameServ.java" i am getting    >> ClassCastEXCEPTION<< at line (**) as below

   " GameHome sh=(GameHome) PortableRemoteObject.narrow(ref,GameHome.class); "

I hope i have described my problem very well and i request you to give me solution so that my client application may call the bean.

********  Waiting for the response. *******

*******************************    END    ****************************************

 
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Question by:sanjeev_1772
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4 Comments
 
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Accepted Solution

by:
naidubs earned 200 total points
ID: 7176721
using reflection try to get class name , so that u will come to know which class ur getting.
code is
Class cls = ref.getClass();
S.O.P("class name"+cls.getName());

uu need to verify the class path and add home&remote classes in client jar file.
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