Design Patterns, Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides; Addison Wesley, 1995 Amazon
Seminal reference for major design patterns
Refactoring: Improving the design of existing code, Martin Fowler; Addison Wesley, 1999
An implementation level complement to the patterns movement. Formalises and provides a vocabulary for the sort of code clean-up that most of us actually spend our working lives carrying out!
Code Complete: A Practical Handbook Of Software Construction, Steve McConnell
very practical, down to earth guidance on the mechanics of coding. Even though published first in 1993, much of its content is remarkably relevant, since his discussions center on guiding ideas of lasting value.
Excellent introduction to the language, and serves as excellent reference for those of any level
The Java Class Libraries, Second Edition, Volume 1 and Volume 2 plus supplement (a pair of books, the first with a blue cover, and the supplement with a yellow cover)
MMAPI Book covers using JSR135 to work with audio/video/tones and midi in Java enabled phones Amazon
Web Services
Java Web Services Architecture - This book provides practical advice to systems architects about integrating XML with networks services. Sample chapers available for download.
Discussion about Books
Opinion on best books for those new to Java:
The Java Programmng Language - Gosling, Arnold, Holmes
Effective Java - Bloch
Java Class Libraries, 2nd edition, Volume 1, plus supplement
The libraries are of course available on line. However, the paper editions have extensive discussions which do not appear in the on line versions. As well, the paper versions give one a better sense of the size of the libraries, and are easier for browsing around and getting familiar with core classes.
-- JohnOHanley - 11 Oct 2003