Why do we need the @EJB annotation at the class level?

Why do we need the @EJB annotation at the class level?
Eg: Why do we need the first piece of code, when the second code seems much simpler .
*1.*
@Stateful
@EJB(name="ejb/TradeLocalNm",
beanInterface=TradeLocal.class)
public class TradeClientBean implements TradeClientRemote {
*2.*
@Stateful
public class TradeClientBean implements TradeClientRemote {
@EJB private TradeLocal trd;
}

I think it is possible to do it in an aggregated level however you need to define your distribution rules in order to get the desired result, you need also to consider that if distribution rules changes and the value after promotional planning returns the same value, it is possible that detailed level are not realigned to the new distribution rule (e.g. regarding another ratio).
Maybe this is one of several causes.
Regards,
Carlos

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I think it is possible to do it in an aggregated level however you need to define your distribution rules in order to get the desired result, you need also to consider that if distribution rules changes and the value after promotional planning returns the same value, it is possible that detailed level are not realigned to the new distribution rule (e.g. regarding another ratio).
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Having problem access the EJB 3 from Web Component

Hi ,
I have an EJB 3 entity AuctionItem and a session ItemProcessor only implements the local interface IItemProcessor, then I use a servlet to access the findAll method in the ItemProcessor. I've created a Enterprise Applicaiton project to contain the ejb jar and the war file, but after I deploy the ear successfully, I couldn't access to my servlet through http://localhost:8080/AuctionWeb/AuctionServlet, it keeps giving me error like follwoing. Do you know why, your help will be very appreciated !
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
java.lang.NullPointerException
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     at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:844)
     at com.sun.enterprise.web.connector.grizzly.ReadTask.executeProcessorTask(ReadTask.java:287)
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          super();
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        out.println("<body>");
        out.println("<h1>Servlet AuctionServlet at " + request.getContextPath () + "</h1>");
        List items = itemProcessor.findAll();
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       out.println(elem.getTitle()+"<br /> ");
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        out.println("</html>");
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package sessions;
import javax.annotation.Resource;
import javax.ejb.Local;
import javax.ejb.Stateless;
import javax.persistence.*;
import javax.sql.DataSource;
import java.util.List;
import entities.AuctionItem;
@Stateless(name = "ItemProcessor")
public class ItemProcessor implements sessions.IItemProcessor {
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          AuctionItem item = new AuctionItem();
          item.setTitle(title);
          item.setValue(value);
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          item.setStatus(status);
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     public String findItemByKey(Long id) {
          AuctionItem item = entityManager.find(AuctionItem.class, id);
          return item.getTitle();
     public List findAll() {
        return entityManager.createQuery("select object(o) from AuctionItem as o").getResultList();
}

The most common reason for this failure is if your web.xml does not refer to the latest web application
.xsd :
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http
://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/x
ml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
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Question on The @EJB Annotaion

Hello everyone,
How does the @EJB annotation works? Does it already assign an instance of the EJB once a field is annotated by it?
For example I have a code below;
public class MyClass {
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}From the code above, either one of the EJB will be used/invoked, making the other EJB not used at all. My concern there is that other wasted EJB instance.
I would appreciate any of your insights on these.
- Pat
Edited by: theevilclown on Apr 27, 2010 11:17 PM

Hi Jack,
This is a good starting point when using Call Library Function node. Check out this Help Page
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Hi Ekaterina,
I have the document to access my Bean from another Bean.
I could access my Bean from a standalone Java class with this code
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Why do we need the @EJB annotation at the class level?

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