Foreword

In the old days (like, 1995) computing servers were only used by a company's employees , i.e., on an intranet. Today every company seems to be on the Internet. They have an order of magnitude: customers, suppliers, distributors , and potentially anyone (or anything) with access to their web site. Companies have been forced to move from local client-server or mainframe computing to a new multitier computing model. They have a completely new set of problems in reliability, scalability, security, application deployment, transaction processing, web interface design, and timely software development.

This book describes a solution to those problems: Java 2 Platform, Enterprise Edition, or J2EE. J2EE extends the Java 2 Platform, Standard Edition to enable "Write Once Run Anywhere" for multi- tier computing. It is an industry standard from dozens of companies who are developing J2EE-compliant products for their customers.

This book is targeted at software developers who are building those products, or who are writing applications on top of them. It is the definitive reference for J2EE and its component models: Enterprise JavaBeans, servlets, and JavaServer Pages. These component models enable the use of Java technology in web servers and application servers as well as with clients in a distributed computing environment.

Part I of the book, the J2EE specification, defines the standard. This standard enables portability of software across products from a wide variety of vendors selling J2EE-compliant server products.

Parts II and III of the book describe servlets and JavaServer Pages, the web server components for the J2EE platform. Servlets and JavaServer Pages provide standards for extending server functionality and the generation of dynamic web content. Servlets define a simple way to process web server requests , while JavaServer Pages provide a simple way of invoking and embedding Java code in HTML and XML templates.

Part IV describes Enterprise JavaBeans, the application server component model for the J2EE platform. In addition to providing a binary standard for portability across products, Enterprise JavaBeans greatly simplify the development of server code by automating the details of transactions, security, scalability, and other complex aspects of server-side computing. They also add value by simplifying the deployment and customization of components to specific installations. This book is a specification and a reference manual. It defines the J2EE platform. For a beginning introduction to J2EE, refer to white papers, documentation, and example code at: http://java.sun.com/j2ee/download.html

You may also want to download or purchase Nick Kassem's Designing Enterprise Applications with the Java 2 Platform, Enterprise Edition , which provides a programmer's guide to J2EE. If you do not have access to a J2EE-compliant product, a reference implementation of J2EE is available for download at the same location. This implementation is suitable for trying out J2EE prior to investing in a third-party product.