Like all "In A Nutshell" books, this isn't probably where you want to start if you are trying to learn the language. Part 1 is set up such that topics are introduced and discussed with code examples, but it is not a "hand-holding" type of explanation. It assumes you are at least familiar with the information at a high-level, and understand the basic core Java fundamentals. If you are at that point, you should be able to learn a lot from the first section.

Part 2 is where an experienced Java GUI programmer will live and breath. There is detailed documentation on each of the classes that are covered, as well as a diagram that shows the class hierarchy within the class, and where the class fits into the overall Java class hierarchy. Once again, it's strictly documentation with no explanation. Don't expect the author to explain how each method in the class works. It's up to you to figure out how the method best integrates into your project.

I can pose the same question I did when I reviewed Java In A Nutshell... Why get this book if I have the online API documentation from Sun? I see them as complimentary. You can probably find much of the reference material in either source. Some will prefer the online hyperlink navigation, while others will appreciate having all the information on a subject in four or five pages that can be thumbed through. I know when I'm stuck on a problem I want both sources!

For Notes/Domino 5 developers, I would say that there is little in this book that would be of value to you as you code a typical Notes/Domino application. While Notes/Domino does support applets within the application, you would most likely code those outside of the Notes/Domino framework. If you are tasked with developing a Java application that uses Notes/Domino APIs to capture some of the inherent power of the platform, then this book would be useful as you develop the GUI interface that you'll need for your project.

Conclusion
If you're a Java developer working with client-side applications, get this book. If you're a Notes/Domino developer looking to use Java in your applications, you should probably focus on the Java In A Nutshell book. This is a very well written book, but the usefulness of the information depends on what type of Java programming you are doing.

The major part of the text (~550 pages) is the reference to the Foundation Classes and lists all of the JFC classes with their class hierarchy structure information, all methods and a brief description of the class. This reference part has the same quality as the references known from the other Java in a Nutshell publications (Java in a Nutshell, Java Enterprise in a Nutshell). It is comprehensive, gives a good overview of each package and lists the class methods in a very readable way. The introduction to packages and classes are brief but cover the essentials very well.

The first ~150 pages of this book give an overview of the Swing architecture and an introduction to the key APIs in the JFC. It covers graphics, printing, data transfer and applets. This part of the book is more problematic than the actual reference part. The selection of topics is limited and not very intuitive (why a hole section on Applets?). Although this introduction is written very well, the it is too short to serve as a tutorial and yet too literary and incomplete to be part of reference manual.

Anyhow, this is a good and complete reference manual that comes handy whenever you don't have access to the online Java API documentation.