Table Of ContentGuide to J2EE: Enterprise Java
Springer-Verlag London Ltd.
Jo hn Hunt and Chris Loftus
Guide to J2EE:
Enterprise Java
, Springer
John Hunt
JayDee Technology Ud, www.jaydeetechnology.co.uk
Chris Loftus
Department of Computer Science, University of Wales, Aberystwyth, UK
www.aber.ac.ukJcompsci
British Library Cataloguing in Publication Data
Hunt,John
Guide to J2EE : enterprise Java
1.Java (Computer program language) 2.Application software
Development
1. Title Il. Loftus, C. W.
005.7'1262
Library of Congress Cataloging-in-Publication Data
Hunt, John, 1964-
Guide to J2EE : enterprise Java / John Hunt and Chris Loftus.
p.cm.
ISBN 978-1-4471-1126-9 ISBN 978-1-4471-0017-1 (eBook)
DOI 10.1007/978-1-4471-0017-1
1. Java (Computer program language) 2. Business--Data processing. 1. Loftus, Chris,
1963-II. Title.
QA76.73.J38H8552003
005.2'762--dc21 2003042427
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted
under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or
transmitted, in any form or by any means, with the prior permis sion in writing of the publishers, or in the
case of reprographic reproduction in accordance with the terms of licences issued by the Copyright
Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers.
ISBN 978-1-4471-1126-9
http://www.springer.co.uk
© Springer-Verlag London 2003
Originally published by Springer-Verlag London Limited in 2003
Softcover reprint ofthe hardcover lst edition 2003
First published 2003
The use of registered names, trademarks etc. in this publication does not imply, even in the absence of a
specific statement, that such names are exempt from the relevant laws and regulations and therefore free for
general use.
The publisher makes no representation, express or implied, with regard to the accuracy of the information
contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that
maybemade.
Typeset by lan Kingston Editorial Services, Nottingham, UK
34/3830-543210 Printed on acid-free paper SPIN 10895318
For my brother, Paul
JH
To Jonathan
CL
Preface
Why This Book?
This book aims to be a practical introduction to all you need to know to design, implement,
deploy and run Java 2 Enterprise Edition (J2EE) technology applications. Such applications build
on the technology provided in the Java 2 Standard Edition (J2SE) by exploiting Servlets, Java
Server Pages {JSPs),Enterprise JavaBeans (EJBs) or some other server side technology (such as
the Java Message Service).
A related question to "Why this book?" is "Why did we write this book?". The answer to
this is that over the last three years we have trained a wide variety of developers in J2EE
technologies. This has been both in industry and academia. We have also been involved in
the design, implementation and deployment of several large J2EE technology applications.
During this time we felt that there was no single book that presented the J2EE technologies
as a whole in a coherent, cohesive and introductory form.
We did of course try to find appropriate books both to provide on our courses as well as
to recommend. In general we found that the books available fell into one of two categories.
They were either focused on one particular aspect of the J2EE (such as servlets/JSPs or
EJBs) or they felt like reference material: to be dipped into as required, but not to be read
cover to cover. This meant that if you wanted to learn a broad cross-section of J2EE technol
ogies you had to take a course, buy multiple books or try to work through large reference
style books with much information repeated in the standalone chapters.
This then is a book to read from cover to cover that will provide a detailed introduction
to almost all aspects of the J2EE. Due to space restrictions it does not contain as much detail
on EJBs as a dedicated EJB book; however, it does cover most of what you are going to need
in the average project. The rest you can get from the EJB documentation provided with the
J2EE or from tutorials on Sun's and others' Web sites (for example see http:/ I
www.javaworld.com/and http://www.planetjava.co.uk/).This is also true of servlets
and JSPs.
vii
viii Preface
Why Tomcat and J80551
A useful question to consider is why did we choose Tomcat and JBoss as the Web application and
EJB application servers respectively? The answer to this is quite simple. We wanted to use freely
available servers that could be accessed by readers of our book at little or no cost. However, we
wanted these servers to be production quality servers that can and are used for real world systems.
The obvious choices for these servers were therefore Tomcat (which is also Sun's reference imple
mentation for a Web application server) and JBoss.
Tomcat
Tomcat is part of the Apache Jakarta project. The Jakarta Project creates and maintains open
source solutions on the Java platform. Individual products are developed by and distributed
through various sub-projects, of which Tomcat is one example. Each sub-project has its own team
of developers and committees, and its own mailing lists and discussion groups.
Tomcat is developed in an open and participatory environment and released under the
Apache Software License. It is one of the most widely used Java Web application servers
around today. It is also used as the reference implementation by Sun for the Servlet and JSP
specifications.
The version used for this book is Tomcat 4.0.3, which supports the Servlet 2.3 specification and
the JSP 1.2 specification. Tomcat can be obtained from Apache using the following URL:
http://jakarta.apache.org/tomcat/index.html
Tomcat 5.0 will support version 1.4 of the J2EE SDK. However, at the time of writing this was
currently in development and not yet available for general use. This version of Tomcat supports
the Servlet 2.4 and the JSP 2.0 specifications.
JBoss
JBoss is an open source, standards-compliant, application server implemented in 100% pure Java
and distributed for free. During 2002 there were over 150,000 downloads per month; JBoss is the
most downloaded Web application server in the world based on the J2EE specification. In a poll
carried out by TogetherSoft JBoss was the choice of 44% of respondents when asked which J2EE
server they use for Enterprise Development, with closest competitor, BEA Web logic, at only 23%
(see http://www. togethercommuni ty. comji ndex. j sp ).JBoss also won the Java World Editor's
Choice 2002 Award for Best Java Application Server. Therefore, although JBoss is open source it is
the most used J2EE EJB application server currently available. Note that JBoss also provides
implementations of the JND!, Java Message Service, distributed transactions etc. It also includes a
simple relational database known as Hypersonic.
When JBoss is combined with Tomcat it provides a complete J2EE stack - that is it offers
support not only for the EJB server but also servlets and JSPs. Thus with JBoss and Tomcat
you need nothing else. The version of JBoss used in this book is JBoss 3.0.0.
Preface ix
You can down load standalone JBoss (or JBoss with a built-in Tomcat) from:
http://www.jboss.org/
Versions of JBoss and Tomcat
As versions of both Tomcat and JBoss may have slightly different deployment requirements or
changes in directory structures we have made the versions of both used in this book available on
the Web site dedicated to this book.
Portability of Code
An import point to note is that J2EE-based applications should be cross-server. That is, if the
developer follows the J2EE guidelines the source code should work whatever J2EE server it is
deployed onto. This means that source code written to run on WebSpehere should run on JBossl
Tomcat or Web Logic. Therefore choosing the JBoss Tomcat stack combination for this book does
not mean that you cannot use the material provided on other servers (although the way that the
source is deployed may differ).
Guide to the J2EE Web Site
We have developed a Web site dedicated to this book and to the material in this book. The web site
URL is:
http://www.guide-to-j2ee.net/
We both believe that software developers learn best by doing and by starting with some
working code and experimenting. Therefore all the source code for the examples in this book is
available on the Web site. Each chapter has its own directory within which the class files are listed
individually. The source code has all been tested using the Java 2 Enterprise Edition (SDK 1.3.1)
using Tomcat 4.0.3 and JBoss 3.0. As new versions of J2EE are released all examples will be tested
against them using the relevant versions of Tomcat and JBoss. Any changes necessitated by a new
release will be noted at the above Web site.
As mentioned earlier, we have also made available the versions of Tomcat and JBoss used
with the examples in this book.
The Web site provides the following:
• The versions of JBoss and Tomcat used.
• All source code, XML files, JSPs and HTML files used in this book.
• Any updates necessitated by more recent releases of the Servlet/JSP or EJB specifications.
x Preface
Structure of the Book
This book is divided into five parts.
Part 1: Background
This part presents the underlying J2EE or server-side technologies that EJBs, servlets, JSPs etc.
rely on. This section therefore covers topics such as JDBC, RMI, JNDI and XML.
Part 2: Enterprise JavaBeans
In this part we present Enterprise JavaBeans (EJBs). EJBs are the J2EE technology used to repre
sent application business logic, persistent data and, through message-driven beans, message
oriented logic.
Part 3: Servlets and JSPs
The presentation or Web tier of a J2EE application is made up of servlets and JSPs. This section
therefore describes these technologies and associated issues such as securing Web applications.
Part 4: Additional technologies
We present a number of advanced J2EE technologies in this section, including J2EE transactions,
EJB security, Web services and SVG (Scalable Vector Graphics, which is an XML technology).
Part 5: Design
This describes the design of J2EE applications and the use of the Design Patterns in Sun's J2EE
Patterns Catalog.
Typographical Conventions
In this book, the standard typeface is Minion. However, source code is set in Letter Gothic (for ex
ample, a = 2 + 3;). A bold font indicates Java keywords, for example:
public class Address extends Object {. .. }
Trademarks
Java, Java 2 Standard Edition, Java 2 Enterprise Edition, Java Development Kit, Solaris, SPARC,
SunOS and Sunsoft are trademarks of Sun Microsystems, Inc. MS-Windows and Windows 95,98,
Preface xi
2000, NT and XP are registered trademarks of Microsoft Corporation. Unix is a registered trade
mark of AT&T. All other brand names are trademarks of their respective holders.
Acknowledgements
We have both benefited from discussions with colleagues both at work and within our social
circles who have in their various ways contributed to this book. In addition all those students and
course delegates that we have taught Java 2 Enterprise Edition technologies to have unknowingly
helped to form the material in this book with their questions, comments and general feedback.
In particular we would like to thank Steve Mabbort, Ben Halton and Will Mepham of
Ja yDee Technology Ltd, and Jon Adams, Denise Cooke and Alex McManus for proof reading
various parts of this book. Thanks also to Steve Mabbort for technical input into the SVG
and Web Services chapters.
John would also like to thank Jay Dee Technology Ltd (http://www . j aydeetechno logy.
co. u k/), and Chris would like to thank the Computer Science Department of the University
of Wales, Aberystwyth (http://www.aber.ac . uk/ compsci /), for their help and support.
Both organizations allowed the authors time and materials to produce this book.
We have both been very lucky to have the help and support of both our partners - without
whom neither of us would have got through this book.
John Hunt and Chris Loftus
