You can download the sourcecode for the examples in the book from any of: http://www.wrox.com ftp://www.wrox.com ftp://www.wrox.co.uk
The sourcecode download also includes ancillary files, such as .gif files containing icons for instance, where they are used in the examples.
If you have any questions on the fine formal detail of Java, the reference works we've used are:
The Java Language Specification, Second Edition (The Java Series) James Gosling et al., Addison-Wesley, ISBN 0-201-31008-2
The Java Virtual Machine Specification Second Edition Tim Lindholm and Frank Yellin, Addison-Wesley, ISBN 0-201-43294-3,
Other sites of interest are: http://www.wrox.com
for support for this book and information on forthcoming Java books. http://p2p.wrox.com
for lists where you can get answers to your Java problems. http://java.sun.com/docs/books/tutorial/index.html
for the JavaSoft tutorials. Follow that Java trail.
and for online magazine reading and opinion, check out: http://www.javaworld.com/javasoft.index.html http://www.javareport.com/ http://www.sys-con.com/java/
We also like the Java Developer Connection, subscribe to it at http://java.sun.com/jdc