Book Image

Tomcat 6 Developer's Guide

Book Image

Tomcat 6 Developer's Guide

Overview of this book

While Tomcat is one of the most popular servlet containers, its inner workings still remain a mystery to many developers. If you only have a superficial familiarity of how this container actually functions, much of its power remains untapped and underutilized. This book will provide you with all that you need to undertand how to effectively use Apache Tomcat. This book begins by providing detailed instructions on building a Tomcat distribution. The next few chapters introduce you to the conceptual underpinnings of web servers, the Java EE and servlet specifications, and the Tomcat container. Subsequent chapters address the key Tomcat components, taking care to provide you with the information needed to understand the internal workings of each component. Detailed examples let you walk through a Tomcat installation, stepping into key Tomcat components, as well as into your own custom servlets. During the course of the book you will encounter various structural components such as the Server and Service; containers such as the Engine, Host, Context, and Wrapper; and helpers such as the Loader, Manager, and Valve. You will also see how Tomcat implements the JNDI API to provide both a directory service for storage agnostic access to its resources, as well as a naming service that implements the Java EE Environment Naming Context. Along the way you will learn how various elements of the servlet 2.5 specification, as well as the HTTP RFCs are implemented by a servlet container. By the end of your journey, you will be able to count yourself as part of the elite minority of Java EE web developers who truly understand what goes on under the covers of a servlet container.
Table of Contents (17 chapters)
Tomcat 6 Developer's Guide
Credits
About the author
Acknowledgement
About the reviewers
Preface

Making a class available


The process of loading a class is kicked off by the invocation of the loadClass() method on a ClassLoader instance.

Loading a class involves two distinct steps, both of which must be successfully completed before a class can be used.

  • Loading the class: In this step, the findClass() method of a ClassLoader instance is used to locate the bytecode for this class. The binary form of a class is represented using a well defined class format and typically exists as a .class file. However, more exotic locations may also be supported. In really mind bending scenarios, the bytecode may even be generated dynamically.

    Once the bytecode that represents the class has been found, the class is defined using the defineClass() method. In this process, the bytecode representation is converted into a java.lang.Class instance.

  • Linking the class: This is an optional step that begins after a class has been successfully loaded. This process is implemented using the resolveClass() method...