I have write a MBean followed the exsample code listed in chap2/ex2. After I deployed it, I could found it successfully displayed in console. But when I use client to test it, I only can get null object from lookup method.

Followed is MBean code:
package com.lenovo.nms.tm;

/**
* Title: MsgCatch
* Description: Used to store message catch.
* Copyright: Copyright (c) 2003
* Company: Lenovo
* @author Sun Fuqiang
* @version 1.0
*/

import java.util.HashMap;
import javax.naming.InitialContext;
import javax.naming.Name;
import javax.naming.NamingException;
import org.jboss.naming.NonSerializableFactory;

public class MsgCatch extends org.jboss.system.ServiceMBeanSupport
implements MsgCatchMBean{

private String jndiName;
private MsgCatchQueue msgCatchQueue = new MsgCatchQueue();

public String getJndiName()
{
return jndiName;
}
public void setJndiName(String jndiName) throws NamingException
{
String oldName = this.jndiName;
this.jndiName = jndiName;
if( super.getState() == STARTED )
{
unbind(oldName);
try
{
rebind();
}
catch(Exception e)
{
NamingException ne = new
NamingException("Failed to update jndiName");
ne.setRootCause(e);
throw ne;
}
}
}

public void startService() throws Exception
{
//jndiName="inmemory/maps/MsgCatch";
System.out.println("Start Service invoked.");
System.out.println(jndiName);
rebind();
}
public void stopService()
{
unbind(jndiName);
}

private void rebind() throws NamingException
{
InitialContext rootCtx = new InitialContext();
Name fullName = rootCtx.getNameParser("").parse(jndiName);
log.info("fullName="+fullName);
NonSerializableFactory.rebind(fullName, msgCatchQueue, true);
}
private void unbind(String jndiName)
{
try
{
InitialContext rootCtx = new InitialContext();
rootCtx.unbind(jndiName);
NonSerializableFactory.unbind(jndiName);
}
catch(NamingException e)
{
log.error("Failed to unbind map", e);
}
}
}

Client test code:
try {
InitialContext ctx = new InitialContext();
Object msgCatchQueue = (Object) ctx.lookup("inmemory/maps/MsgCatch");
String s=new String();
s="OK,I am Richard.";
//msgCatchQueue.addTail(s);
int i=0;
} catch (Exception e) {
e.printStackTrace();
}
}
msgCatchQueue always is null.

could anyone met this problem before?

Thanks.