This book is aimed at two main groups.
The primary audience is developers who are familiar with the basics of the Java programming language itself but have little or no experience with server-side applications. For you, virtually the entire book should be valuable ; with the possible exception of the JSP 2.0 expression language (which is not applicable if you are using a server that is compliant only with JSP 1.2), you are likely to use capabilities from almost every chapter in almost every real-world application.
The second group is composed of people who are familiar with basic servlet and JSP development and want to learn how to make use of the new capabilities we just described. If you are in this category, you can skim many of the chapters, focusing on the capabilities that are new in servlets 2.4, JSP 2.0, or JDBC 3.0.
Although this book is well suited for both experienced servlet and JSP programmers and newcomers to the technology, it assumes that you are familiar with basic Java programming. You don't have to be an expert Java developer, but if you know nothing about the Java programming language, this is not the place to start. After all, servlet and JSP technology is an application of the Java programming language. If you don't know the language, you can't apply it. So, if you know nothing about basic Java development, start with a good introductory book like Thinking in Java , Core Java , or Core Web Programming . Come back here after you are comfortable with at least the basics.