Software and versions This book covers Enterprise JavaBeans version 2.0 and version 1. 1, including all optional features. It uses Java language features from the Java 1.2 platform and JDBC. Because the focus of this book is to develop vendor-independent Enterprise JavaBeans components and solutions, I have stayed away from proprietary extensions and vendor-dependent idioms. Any EJB-compliant server can be used with this book; you should be familiar with that server's specific installation, deployment, and runtime management procedures to work with the examples This book covers both ejb 2.0 and ejb 1.1. These two versions have a lot in common, but when they differ, chapters, or text with in a chapter, that specific to each version is clearly marked. Feel free to skip version-specific sections that de not concern you. Unless indicated, the source code in this book has been written or both ejb 2. 0 and 1.1 Examples developed in this book are available from ftp:: /ftp oreilly. com/pub/examples/java/ejb. The examples are organized by Example Workbooks Although EJB applications themselves are portable, the manor in which you install and run EJB products vary wildly from one vendor to the next. For this reason its nearly impossible to cover all the ejb products available, so we have chosen a radical but very effective way to address these differences To help you deploy the book examples in different EJB products, the author will publish several free workbooks"which are used along with this book to run the examples on specific commercial and non-commerc servers. The workbook for a specific product will address that products most advanced server. So for example, if the vendor supports EJB 2.0, then the examples in the workbook will address EJB 2.0 features. If, on the other hand, the vendor only supports EJ then the examples in the workbook will be specific to EJB 1.1 Although there are plans to publish workbooks for as many different EJB server, at least two workbooks will be made available immediately. These workbooks free on-line in PDF format. The workbooks are all available at http://www.oreilly.com/catalog/entjbeans3/orhttp:/www.monson-haefel.com Copyright(c)2001 OReilly Associates 6
DRAFT, 10/21/017/6/2001 Copyright (c) 2001 O'Reilly & Associates 6 Software and Versions This book covers Enterprise JavaBeans version 2.0 and version 1.1, including all optional features. It uses Java language features from the Java 1.2 platform and JDBC. Because the focus of this book is to develop vendor-independent Enterprise JavaBeans components and solutions, I have stayed away from proprietary extensions and vendor- dependent idioms. Any EJB-compliant server can be used with this book; you should be familiar with that server’s specific installation, deployment, and runtime management procedures to work with the examples. This book covers both EJB 2.0 and EJB 1.1. These two versions have a lot in common, but when they differ, chapters, or text with in a chapter, that specific to each version is clearly marked. Feel free to skip version-specific sections that do not concern you. Unless indicated, the source code in this book has been written for both EJB 2.0 and 1.1 Examples developed in this book are available from ftp://ftp.oreilly.com/pub/examples/java/ejb. The examples are organized by chapter. Example Workbooks Although EJB applications themselves are portable, the manor in which you install and run EJB products vary wildly from one vendor to the next. For this reason its nearly impossible to cover all the EJB products available, so we have chosen a radical but very effective way to address these differences: Workbooks. To help you deploy the book examples in different EJB products, the author will publish several free “workbooks” which are used along with this book to run the examples on specific commercial and non-commercial EJB servers. The workbook for a specific product will address that products most advanced server. So for example, if the vendor supports EJB 2.0, then the examples in the workbook will address EJB 2.0 features. If, on the other hand, the vendor only supports EJB 1.1, then the examples in the workbook will be specific to EJB 1.1. Although there are plans to publish workbooks for as many different EJB server, at least two workbooks will be made available immediately. These workbooks are free on-line in PDF format. The workbooks are all available at http://www.oreilly.com/catalog/entjbeans3/ or http://www.monson-haefel.com
Conventions Italic is used for Filenames and pat stnames. domain names. URLS and email addresses v terms where they are defined th is used for Code examples and fragments Class, variable, and method names, and Java keywords used within the text SQL commands, table names, and column names XML elements and tags Constant width bold is used for emphasis in some code examples Constant width italic is used to indicate text that is replaceable. For example, in BeanNamePK, you would replace BeanName with a specific bean An Enterprise JavaBean consists of many parts; it's not a single object, but a collection of objects and interfaces. To refer to an Enterprise Java Bean as a whole, we use the name of its business name in Roman type followed by the acronym, EJB(Enterprise JavaBean). For example, we will refer to the Customer EJB when we want to talk about the enterprise bean in general. If we put the name in a constant width font, we are referring explicitly to the beans the interface. So Customerremote is the remote interface that define business methods of the customer ejb Comments and Questions Please address comments and questions concerning this book to the publisher O'Reilly Associates, Inc 101 Morris Street Sebastopol, CA 95472 (800)998-9938(in the U.S. or Canada) (707)8290104(fax) You can also send us messages electronically. To be put on our mailing Copyright(c)2001 OReilly Associates 7
DRAFT, 10/21/017/6/2001 Copyright (c) 2001 O'Reilly & Associates 7 Conventions Italic is used for: · Filenames and pathnames · Hostnames, domain names, URLs, and email addresses · New terms where they are defined Constant width is used for: · Code examples and fragments · Class, variable, and method names, and Java keywords used within the text · SQL commands, table names, and column names · XML elements and tags Constant width bold is used for emphasis in some code examples. Constant width italic is used to indicate text that is replaceable. For example, in BeanNamePK, you would replace BeanName with a specific bean name. An Enterprise JavaBean consists of many parts; it’s not a single object, but a collection of objects and interfaces. To refer to an Enterprise JavaBean as a whole, we use the name of its business name in Roman type followed by the acronym, EJB (Enterprise JavaBean). For example, we will refer to the Customer EJB when we want to talk about the enterprise bean in general. If we put the name in a constant width font, we are referring explicitly to the bean’s remote interface. So CustomerRemote is the remote interface that defines the business methods of the Customer EJB. Comments and Questions Please address comments and questions concerning this book to the publisher: O’Reilly & Associates, Inc. 101 Morris Street Sebastopol, CA 95472 (800) 998-9938 (in the U.S. or Canada) (707) 829-0515 (international or local) (707) 829-0104 (fax) You can also send us messages electronically. To be put on our mailing list or to request a catalog, send email to:
To ask technical questions or comment on the book, send email to bookquestions@oreilly. a web site for the book, where we'll list errata and any plans for future ditions. You can access this page at For more information about this book and others, see the O Reilly web site at http://www.oreilly.com/ The author maintains a web site for the discussion of ejb and related distributed computingtechnologies(http://www.ejbnow.com).EjbNow.coMprovidesnews about this book as well as code tips, articles, and an extensive list of links to EJB resources Acknowledgments While there is only one name on the cover of this book, the credit for development and delivery is shared by many individuals. Michael Loukides, my editor, was pivotal to the success of every edition of this book. Without his experience, craft, and guidance, this book would not have been possible Many expert technical reviewers helped ensure that the material was technically accurate and true to the spirit of Enterprise JavaBeans. Of special note are David Chappell of David Chappell Associates, Jim Farley, author of Java TM Distributed Computing(O'Reilly, 1998), Greg Nyberg of ObjectPartners, Prasad Muppirala and Shannon Pieper of BORN Information Services, contributed greatly to the technical accuracy of this book and brought a combination of industry and real-world experience to bear, helping to make this one of the best books on Enterprise Java Beans published today. Special thanks also go to Sriram Srinivasan of BEA, Anne Thomas of Sun MicrosystemsandlanmCcallionofIbmHursley,TimRohalyofjgUru.com, James D. Frentress of ITM Corp, Andrzej Jan Taramina of Accredo Systems Marc Loy, co-author of JavaTM Swing(O Reilly, 1998), Don Weiss of Step 1 Mike Slinn of The Dialog Corporation, and Kevin Dick of Kevin Dick Associates. The contributions of these technical experts were critical to the echnical and conceptual accuracy of earlier editions of this book. Others I would like to thank include Maggie Mezquita, Greg Hartzel, John Klug and Jon Jamsa of bORN Information who all suffered though the first draft of the first edition long ago to provide valuable feedback. Thanks also to Vlad Matena and Mark Hapner of Sun Microsystems, the primary architects of Enterprise JavaBeans; Linda DeMichiel, EJB 2.0 specification lead Copyright(c)2001 OReilly Associates 8
DRAFT, 10/21/017/6/2001 Copyright (c) 2001 O'Reilly & Associates 8 info@oreilly.com To ask technical questions or comment on the book, send email to: bookquestions@oreilly.com We have a web site for the book, where we’ll list errata and any plans for future editions. You can access this page at: http://www.oreilly.com/catalog/entjbeans2/ For more information about this book and others, see the O’Reilly web site at: http://www.oreilly.com/ The author maintains a web site for the discussion of EJB and related distributed computing technologies (http://www.ejbnow.com). EJBNow.com provides news about this book as well as code tips, articles, and an extensive list of links to EJB resources. Acknowledgments While there is only one name on the cover of this book, the credit for its development and delivery is shared by many individuals. Michael Loukides, my editor, was pivotal to the success of every edition of this book. Without his experience, craft, and guidance, this book would not have been possible. Many expert technical reviewers helped ensure that the material was technically accurate and true to the spirit of Enterprise JavaBeans. Of special note are David Chappell of David Chappell & Associates, Jim Farley, author of Java™ Distributed Computing (O’Reilly, 1998), Greg Nyberg of ObjectPartners, Prasad Muppirala and Shannon Pieper of BORN Information Services, …………. They contributed greatly to the technical accuracy of this book and brought a combination of industry and real-world experience to bear, helping to make this one of the best books on Enterprise JavaBeans published today. Special thanks also go to Sriram Srinivasan of BEA, Anne Thomas of Sun Microsystems, and Ian McCallion of IBM Hursley, Tim Rohaly of jGuru.com, James D. Frentress of ITM Corp., Andrzej Jan Taramina of Accredo Systems, Marc Loy, co-author of Java™ Swing (O’Reilly, 1998), Don Weiss of Step 1, Mike Slinn of The Dialog Corporation, and Kevin Dick of Kevin Dick & Associates. The contributions of these technical experts were critical to the technical and conceptual accuracy of earlier editions of this book. Others I would like to thank include Maggie Mezquita, Greg Hartzel, John Klug and Jon Jamsa of BORN Information who all suffered though the first draft of the first edition so long ago to provide valuable feedback. Thanks also to Vlad Matena and Mark Hapner of Sun Microsystems, the primary architects of Enterprise JavaBeans; Linda DeMichiel, EJB 2.0 specification lead;
and Bonnie Kellett J2EE Program Manager - they were all willing to answer several of my most complex questions. Thanks to all the participants in the EJB INTEREST mailing list hosted by Sun Microsystems for their interesting and sometimes controversial, but always informative, postings over the past four Finally, the most sincere gratitude must be extended to my wife, Hollie, for supporting and assisting me through three years of painstaking research and writing which were required to produce three editions of this book. Without her unfailing support and love, this book would not have been completed Copyright(c)2001 OReilly Associates
DRAFT, 10/21/017/6/2001 Copyright (c) 2001 O'Reilly & Associates 9 and Bonnie Kellett J2EE Program Manager – they were all willing to answer several of my most complex questions. Thanks to all the participants in the EJBINTEREST mailing list hosted by Sun Microsystems for their interesting and sometimes controversial, but always informative, postings over the past four years. Finally, the most sincere gratitude must be extended to my wife, Hollie, for supporting and assisting me through three years of painstaking research and writing which were required to produce three editions of this book. Without her unfailing support and love, this book would not have been completed
Introduction This book is about Enterprise JavaBeans 1. I and 2.0 the second and third versions of the Enterprise JavaBeans specification. Just as the Java platform has revolutionized the way we think about software development, Enterprise Java Beans has revolutionized the way we think about developing mission-critical enterprise software. It combines server-side components with distributed object technologies and asynchronous messaging to greatly simplify the task of application development. It automatically takes into account many of the requirements of business systems: security, resource pooling, persistence concurrency, and transactional integrity This book shows you how to use Enterprise JavaBeans to develop scalable, portable business systems. But before we can start talking about EJB itself, we'll need a brief introduction to the technologies addressed by EJB, such as component models distributed objects, component transaction monitors (CTMs), and asynchronous essaging. It's particularly important to have a basic understanding of component transaction monitors, the technology that lies beneath EJB. In Chapters 2 and 3, we'll start looking at EJB itself and see how enterprise beans are put together. The rest of this book is devoted to developing enterprise beans for an imaginary business and dis cussing advanced issues It is assumed that you' re already familiar with Java; if you're not, Exploring Java TM by Patrick Niemeyer and Josh Peck is an excellent introduction. This book also assumes that Copyright(c)2001 OReilly Associates
DRAFT 10/21/0107/06/01 Copyright (c) 2001 O'Reilly & Associates 1 Introduction This book is about Enterprise JavaBeans 1.1 and 2.0 the second and third versions of the Enterprise JavaBeans specification. Just as the Java platform has revolutionized the way we think about software development, Enterprise JavaBeans has revolutionized the way we think about developing mission-critical enterprise software. It combines server-side components with distributed object technologies and asynchronous messaging to greatly simplify the task of application development. It automatically takes into account many of the requirements of business systems: security, resource pooling, persistence, concurrency, and transactional integrity. This book shows you how to use Enterprise JavaBeans to develop scalable, portable business systems. But before we can start talking about EJB itself, we’ll need a brief introduction to the technologies addressed by EJB, such as component models, distributed objects, component transaction monitors (CTMs), and asynchronous messaging. It’s particularly important to have a basic understanding of component transaction monitors, the technology that lies beneath EJB. In Chapters 2 and 3, we’ll start looking at EJB itself and see how enterprise beans are put together. The rest of this book is devoted to developing enterprise beans for an imaginary business and dis cussing advanced issues. It is assumed that you’re already familiar with Java; if you’re not, Exploring Java™ by Patrick Niemeyer and Josh Peck is an excellent introduction. This book also assumes that