Document Information


Part I Introduction

1.  Overview

2.  Using the Tutorial Examples

Part II The Web Tier

3.  Getting Started with Web Applications

4.  Java Servlet Technology

5.  JavaServer Pages Technology

6.  JavaServer Pages Documents

7.  JavaServer Pages Standard Tag Library

8.  Custom Tags in JSP Pages

9.  Scripting in JSP Pages

10.  JavaServer Faces Technology

11.  Using JavaServer Faces Technology in JSP Pages

12.  Developing with JavaServer Faces Technology

13.  Creating Custom UI Components

14.  Configuring JavaServer Faces Applications

15.  Internationalizing and Localizing Web Applications

Part III Web Services

16.  Building Web Services with JAX-WS

17.  Binding between XML Schema and Java Classes

18.  Streaming API for XML

19.  SOAP with Attachments API for Java

Part IV Enterprise Beans

20.  Enterprise Beans

21.  Getting Started with Enterprise Beans

22.  Session Bean Examples

23.  A Message-Driven Bean Example

simplemessage Example Application Overview

The simplemessage Application Client

Packaging, Deploying, and Running the simplemessage Example

Creating the Administered Objects for the simplemessage Example

Building, Deploying, and Running the simplemessage Application Using NetBeans IDE

Building, Deploying, and Running the simplemessage Application Using Ant

Removing the Administered Objects for the simplemessage Example

Creating Deployment Descriptors for Message-Driven Beans

Part V Persistence

24.  Introduction to the Java Persistence API

25.  Persistence in the Web Tier

26.  Persistence in the EJB Tier

27.  The Java Persistence Query Language

Part VI Services

28.  Introduction to Security in the Java EE Platform

29.  Securing Java EE Applications

30.  Securing Web Applications

31.  The Java Message Service API

32.  Java EE Examples Using the JMS API

33.  Transactions

34.  Resource Connections

35.  Connector Architecture

Part VII Case Studies

36.  The Coffee Break Application

37.  The Duke's Bank Application

Part VIII Appendixes

A.  Java Encoding Schemes

B.  About the Authors



The Message-Driven Bean Class

The code for the SimpleMessageBean class illustrates the requirements of a message-driven bean class:

  • It must be annotated with the @MessageDriven annotation if it does not use a deployment descriptor.

  • The class must be defined as public.

  • The class cannot be defined as abstract or final.

  • It must contain a public constructor with no arguments.

  • It must not define the finalize method.

It is recommended, but not required, that a message-driven bean class implement the message listener interface for the message type it supports. A bean that supports the JMS API implements the javax.jms.MessageListener interface.

Unlike session beans and entities, message-driven beans do not have the remote or local interfaces that define client access. Client components do not locate message-driven beans and invoke methods on them. Although message-driven beans do not have business methods, they may contain helper methods that are invoked internally by the onMessage method.

For the Application Server, the @MessageDriven annotation typically contains a mappedName element that specifies the JNDI name of the destination from which the bean will consume messages. For complex message-driven beans there can also be an activationconfig element containing @ActivationConfigProperty annotations used by the bean. See A Java EE Application That Uses the JMS API with a Session Bean for an example.

A message-driven bean can also inject a MessageDrivenContext resource. Commonly you use this resource to call the setRollbackOnly method to handle exceptions for a bean that uses container-managed transactions.

Therefore, the first few lines of the SimpleMessageBean class look like this:

public class SimpleMessageBean implements MessageListener {
    private MessageDrivenContext mdc;

The onMessage Method

When the queue receives a message, the EJB container invokes the message listener method or methods. For a bean that uses JMS, this is the onMessage method of the MessageListener interface.

A message listener method must follow these rules:

  • The method must be declared as public.

  • The method must not be declared as final or static.

The onMessage method is called by the bean’s container when a message has arrived for the bean to service. This method contains the business logic that handles the processing of the message. It is the message-driven bean’s responsibility to parse the message and perform the necessary business logic.

The onMessage method has a single argument: the incoming message.

The signature of the onMessage method must follow these rules:

  • The return type must be void.

  • The method must have a single argument of type javax.jms.Message.

In the SimpleMessageBean class, the onMessage method casts the incoming message to a TextMessage and displays the text:

public void onMessage(Message inMessage) {
    TextMessage msg = null;

    try {
        if (inMessage instanceof TextMessage) {
            msg = (TextMessage) inMessage;
  "MESSAGE BEAN: Message received: " +
        } else {
            logger.warning("Message of wrong type: " +
    } catch (JMSException e) {
    } catch (Throwable te) {