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

Java class loading


In some development environments, the developer must choose whether to use static or dynamic linking. The choice is whether a compiled executable statically contains all its library dependencies within itself, or whether it is dynamically able to locate and load its dependencies at runtime.

With Java, this choice does not exist, as all programs use dynamic linking. The loading process begins when the java command is invoked, and the application's main class is loaded into the JVM. All classes referenced by the main() method are then loaded lazily, and made available to the JVM for execution, as references to these classes are encountered.

The bytes that represent a given class usually reside on disk as a file with a .class extension, called a class file. However, the bytes associated with a class could just as easily be retrieved from across a network.

The job of locating a class's bytes and using them to instantiate a new instance of the java.lang.Class class falls to...