There are at least three good reasons you could be holding this book in your hands right now:
You are a Java programmer who has worked largely on front-end systems, such as browser-based applets, and you would like to learn how to implement the delicate internal clockwork that makes a modern e-commerce site work.
You are an established e-commerce developer moving from tools such as ASP and CGI programming into a JSP environment and looking for a complete walkthrough of a basic implementation.
You are a student or entry-level programmer looking for a good introduction to object-oriented design.
It's my fond hope that no matter which of these ...