Preface

This book describes a standard approach to designing multitier enterprise applications with the Java^TM 2 Platform, Enterprise Edition. The book does not contain information on how to use individual J2EE^TM technologies to develop applications, but rather focuses on guidelines for distributing application functionality across tiers and choosing among design options within each tier.

The book describes the principles and technologies employed in building J2EE applications and the specific approach adopted by a sample application. Striking a balance between specificity on the one hand, and articulating broader principles on the other, is never easy. The hope is that the principles presented are both consistent with and complement the sample application documented in the book.

This book is most relevant to IT managers, system architects, and enterprise application developers considering a transition to or intending to use the J2EE platform or vendors providing J2EE products.

How This Book Is Organized

This book contains the following chapters:

Chapter 1, "Introduction," discusses challenges in building enterprise applications and describes how the J2EE platform addresses those challenges. The chapter also discusses application scenarios that the J2EE platform supports.

Chapter 2, "J2EE Platform Technologies," provides an overview of the component, service, and communication technologies supported by the J2EE platform.

Chapter 3, "The Client Tier," presents implementation options for J2EE clients and provides guidelines for choosing among these options.

Chapter 4, "The Web Tier," describes technologies available for supporting development in the Web tier. It includes guidelines and techniques for using J2EE Web components and describes several Web application architectures.

Chapter 5, "The Enterprise JavaBeans Tier," describes the capabilities of the EJB tier of the J2EE platform and discusses design choices for implementing business logic.

Chapter 6, "The Enterprise Information System Tier," describes recommended approaches for accessing enterprise information systems and how J2EE components must be configured to access them.

Chapter 7, "Packaging and Deployment," describes the capabilities provided by the J2EE platform for packaging and deploying J2EE applications, provides heuristics and practical tips on how to use these capabilities, and provides recommendations to the vendors who provide deployment tools.

Chapter 8, "Transaction Management," describes the transaction services provided by the J2EE platform and provides recommendations on how to best use those services.

Chapter 9, "Security," describes the mapping of the J2EE security model to enterprise computing environments and infrastructures.

Chapter 10, "The Sample Application," illustrates the J2EE programming model in the context of an in-depth description of a multitier J2EE application.

"Glossary," is a list of words and phrases found in this book and their definitions.

Obtaining the Sample Application

You can download the sample application described in this book from:

http://java.sun.com/j2ee/download.html

The sample application requires a J2EE v1.2 compliant platform on which to run. From the sample application download page you can also download Sun's J2EE SDK, a freely available implementation of the J2EE v1.2 platform.

Related Information

Pointers to J2EE documentation can be found at:

http://java.sun.com/j2ee/docs.html

For information on how to use the J2EE SDK to construct multitier enterprise applications refer to the J2EE Developer's Guide, available at:

http://java.sun.com/j2ee/j2sdkee/techdocs/index.html

The J2EE technologies cited in this book are described in their specifications:

Java^TM 2 Platform, Enterprise Edition Specification, Version 1.2 (J2EE specification). Copyright 1999, Sun Microsystems, Inc. Available at http://java.sun.com/j2ee/download.html.

Java^TM 2 Platform, Standard Edition, Version 1.2.2 (J2SE specification). Copyright 1993-99, Sun Microsystems, Inc. Available at http://java.sun.com/products/jdk/1.2/docs/api/index.html.

Java^TM Servlet Specification, Version 2.2 (Servlet specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/servlet.

JavaServer Pages^TM Specification, Version 1.1 (JSP specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jsp.

Enterprise JavaBeans^TMSpecification, Version 1.1 (EJB specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/ejb.

JDBC^TM 2.0 API (JDBC specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jdbc.

JDBC^TM 2.0 Standard Extension API (JDBC extension specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jdbc.

Java^TM Transaction API, Version 1.0.1 (JTA specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jta.

Java^TM Transaction Service, Version 0.95 (JTS specification). Copyright 1997-1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jts.

Java Naming and Directory Interface^TM, Version 1.2 (JNDI specification). Copyright 1998, 1999, Sun Microsystems, Inc. Available at http://java.sun.com/products/jndi.

Java IDL. Copyright 1993-99, Sun Microsystems, Inc. Available at http://java.sun.com/products/jdk/1.2/docs/guide/idl/index.html.

RMI over IIOP 1.0.1. Available at http://java.sun.com/products/rmi-iiop.

Java^TM Message Service, Version 1.0.2 (JMS specification). Copyright 1998, Sun Microsystems, Inc. Available at http://java.sun.com/products/jms.

JavaMail^TM API Design Specification, Version 1.1 (JavaMail specification). Copyright 1998, Sun Microsystems, Inc. Available at http://java.sun.com/products/javamail.

JavaBeans^TM Activation Framework Specification, Version 1.0.1 (JAF specification). Copyright 1998, Sun Microsystems, Inc. Available at http://java.sun.com/beans/glasgow/jaf.html.

Typographic Conventions

Table 1 describes the typographic conventions used in this book. Typographic Conventions Typeface or Symbol Meaning Example AaBbCc123 The names of commands, files, and directories; interface, class, method, and deployment descriptor element names; programming language keywords Edit the file Main.jsp. How to retrieve a UserTransaction object. Specify the resource-ref element. AaBbCc123 Variable name The files are named XYZfile. AaBbCc123 Book titles, new words or terms, or words to be emphasized Read Chapter 6 in User's Guide. These are called class options. You must be root to do this.

Typographic Conventions
Typeface or Symbol	Meaning	Example
`AaBbCc123`	The names of commands, files, and directories; interface, class, method, and deployment descriptor element names; programming language keywords	Edit the file `Main.jsp`. How to retrieve a `UserTransaction` object. Specify the `resource-ref` element`.`
AaBbCc123	Variable name	The files are named XYZ`file`.
AaBbCc123	Book titles, new words or terms, or words to be emphasized	Read Chapter 6 in User's Guide. These are called class options. You must be root to do this.

Acknowledgments

This book is the result of many people's efforts.

Each Enterprise Team member had primary responsibility for one chapter and made significant contributions to other chapters. In addition, Danny Coward wrote the initial draft of the deployment chapter.

The authors of the J2EE specifications and the developers of the reference implementation provided useful input at various points during the development of the J2EE programming model.

We are indebted to Rick Cattell, Bill Shannon, Mark Hapner, John Crupi, Sean Brydon, and many other reviewers who provided feedback on early versions of the manuscript.

Jim Inscore and Stephanie Bodoff provided editorial oversight of this project.

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