Document Information


Part I Introduction

1.  Overview

2.  Using the Tutorial Examples

Part II The Web Tier

3.  Getting Started with Web Applications

4.  JavaServer Faces Technology

5.  Introduction to Facelets

6.  Expression Language

7.  Using JavaServer Faces Technology in Web Pages

8.  Using Converters, Listeners, and Validators

9.  Developing with JavaServer Faces Technology

10.  JavaServer Faces Technology: Advanced Concepts

11.  Using Ajax with JavaServer Faces Technology

12.  Composite Components: Advanced Topics and Example

13.  Creating Custom UI Components and Other Custom Objects

14.  Configuring JavaServer Faces Applications

15.  Java Servlet Technology

16.  Uploading Files with Java Servlet Technology

17.  Internationalizing and Localizing Web Applications

Part III Web Services

18.  Introduction to Web Services

19.  Building Web Services with JAX-WS

20.  Building RESTful Web Services with JAX-RS

21.  JAX-RS: Advanced Topics and Example

Part IV Enterprise Beans

22.  Enterprise Beans

23.  Getting Started with Enterprise Beans

24.  Running the Enterprise Bean Examples

25.  A Message-Driven Bean Example

26.  Using the Embedded Enterprise Bean Container

27.  Using Asynchronous Method Invocation in Session Beans

Part V Contexts and Dependency Injection for the Java EE Platform

28.  Introduction to Contexts and Dependency Injection for the Java EE Platform

29.  Running the Basic Contexts and Dependency Injection Examples

30.  Contexts and Dependency Injection for the Java EE Platform: Advanced Topics

31.  Running the Advanced Contexts and Dependency Injection Examples

Part VI Persistence

32.  Introduction to the Java Persistence API

33.  Running the Persistence Examples

34.  The Java Persistence Query Language

35.  Using the Criteria API to Create Queries

36.  Creating and Using String-Based Criteria Queries

37.  Controlling Concurrent Access to Entity Data with Locking

38.  Using a Second-Level Cache with Java Persistence API Applications

Part VII Security

39.  Introduction to Security in the Java EE Platform

40.  Getting Started Securing Web Applications

41.  Getting Started Securing Enterprise Applications

42.  Java EE Security: Advanced Topics

Part VIII Java EE Supporting Technologies

43.  Introduction to Java EE Supporting Technologies

44.  Transactions

45.  Resources and Resource Adapters

46.  The Resource Adapter Example

47.  Java Message Service Concepts

Overview of the JMS API

What Is Messaging?

What Is the JMS API?

When Can You Use the JMS API?

How Does the JMS API Work with the Java EE Platform?

The JMS API Programming Model

JMS Administered Objects

JMS Connection Factories

JMS Destinations

JMS Connections

JMS Sessions

JMS Message Producers

JMS Message Consumers

JMS Message Listeners

JMS Message Selectors

JMS Messages

Message Headers

Message Properties

Message Bodies

JMS Queue Browsers

JMS Exception Handling

Creating Robust JMS Applications

Using Basic Reliability Mechanisms

Controlling Message Acknowledgment

Specifying Message Persistence

Setting Message Priority Levels

Allowing Messages to Expire

Creating Temporary Destinations

Using Advanced Reliability Mechanisms

Creating Durable Subscriptions

Using JMS API Local Transactions

Using the JMS API in Java EE Applications

Using @Resource Annotations in Enterprise Bean or Web Components

Using Session Beans to Produce and to Synchronously Receive Messages

Managing JMS Resources in Session Beans

Managing Transactions in Session Beans

Using Message-Driven Beans to Receive Messages Asynchronously

Managing Distributed Transactions

Using the JMS API with Application Clients and Web Components

Further Information about JMS

48.  Java Message Service Examples

49.  Bean Validation: Advanced Topics

50.  Using Java EE Interceptors

Part IX Case Studies

51.  Duke's Bookstore Case Study Example

52.  Duke's Tutoring Case Study Example

53.  Duke's Forest Case Study Example



Basic JMS API Concepts

This section introduces the most basic JMS API concepts, the ones you must know to get started writing simple application clients that use the JMS API.

The next section introduces the JMS API programming model. Later sections cover more advanced concepts, including the ones you need in order to write applications that use message-driven beans.

JMS API Architecture

A JMS application is composed of the following parts.

  • A JMS provider is a messaging system that implements the JMS interfaces and provides administrative and control features. An implementation of the Java EE platform includes a JMS provider.

  • JMS clients are the programs or components, written in the Java programming language, that produce and consume messages. Any Java EE application component can act as a JMS client.

  • Messages are the objects that communicate information between JMS clients.

  • Administered objects are preconfigured JMS objects created by an administrator for the use of clients. The two kinds of JMS administered objects are destinations and connection factories, described in JMS Administered Objects.

Figure 47-2 illustrates the way these parts interact. Administrative tools allow you to bind destinations and connection factories into a JNDI namespace. A JMS client can then use resource injection to access the administered objects in the namespace and then establish a logical connection to the same objects through the JMS provider.

Figure 47-2 JMS API Architecture

Diagram of JMS API architecture, showing administrative tool, JMS client, JNDI namespace, and JMS provider

Messaging Domains

Before the JMS API existed, most messaging products supported either the point-to-point or the publish/subscribe approach to messaging. The JMS specification provides a separate domain for each approach and defines compliance for each domain. A stand-alone JMS provider can implement one or both domains. A Java EE provider must implement both domains.

In fact, most implementations of the JMS API support both the point-to-point and the publish/subscribe domains, and some JMS clients combine the use of both domains in a single application. In this way, the JMS API has extended the power and flexibility of messaging products.

The JMS specification goes one step further: It provides common interfaces that enable you to use the JMS API in a way that is not specific to either domain. The following subsections describe the two messaging domains and the use of the common interfaces.

Point-to-Point Messaging Domain

A point-to-point (PTP) product or application is built on the concept of message queues, senders, and receivers. Each message is addressed to a specific queue, and receiving clients extract messages from the queues established to hold their messages. Queues retain all messages sent to them until the messages are consumed or expire.

PTP messaging, illustrated in Figure 47-3, has the following characteristics:

  • Each message has only one consumer.

  • A sender and a receiver of a message have no timing dependencies. The receiver can fetch the message whether or not it was running when the client sent the message.

  • The receiver acknowledges the successful processing of a message.

Figure 47-3 Point-to-Point Messaging

Diagram of point-to-point messaging, showing Client 1 sending a message to a queue, and Client 2 consuming and acknowledging the message

Use PTP messaging when every message you send must be processed successfully by one consumer.

Publish/Subscribe Messaging Domain

In a publish/subscribe (pub/sub) product or application, clients address messages to a topic, which functions somewhat like a bulletin board. Publishers and subscribers are generally anonymous and can dynamically publish or subscribe to the content hierarchy. The system takes care of distributing the messages arriving from a topic’s multiple publishers to its multiple subscribers. Topics retain messages only as long as it takes to distribute them to current subscribers.

Pub/sub messaging has the following characteristics.

  • Each message can have multiple consumers.

  • Publishers and subscribers have a timing dependency. A client that subscribes to a topic can consume only messages published after the client has created a subscription, and the subscriber must continue to be active in order for it to consume messages.

The JMS API relaxes this timing dependency to some extent by allowing subscribers to create durable subscriptions, which receive messages sent while the subscribers are not active. Durable subscriptions provide the flexibility and reliability of queues but still allow clients to send messages to many recipients. For more information about durable subscriptions, see Creating Durable Subscriptions.

Use pub/sub messaging when each message can be processed by any number of consumers (or none). Figure 47-4 illustrates pub/sub messaging.

Figure 47-4 Publish/Subscribe Messaging

Diagram of pub/sub messaging, showing Client 1 publishing a message to a topic, and the message being delivered to two subscribers to the topic

Programming with the Common Interfaces

Version 1.1 of the JMS API allows you to use the same code to send and receive messages under either the PTP or the pub/sub domain. The destinations you use remain domain-specific, and the behavior of the application will depend in part on whether you are using a queue or a topic. However, the code itself can be common to both domains, making your applications flexible and reusable. This tutorial describes and illustrates these common interfaces.

Message Consumption

Messaging products are inherently asynchronous: There is no fundamental timing dependency between the production and the consumption of a message. However, the JMS specification uses this term in a more precise sense. Messages can be consumed in either of two ways:

  • Synchronously: A subscriber or a receiver explicitly fetches the message from the destination by calling the receive method. The receive method can block until a message arrives or can time out if a message does not arrive within a specified time limit.

  • Asynchronously: A client can register a message listener with a consumer. A message listener is similar to an event listener. Whenever a message arrives at the destination, the JMS provider delivers the message by calling the listener’s onMessage method, which acts on the contents of the message.