This book, Learning Java, is actually the fourth edition—reworked and retitled—of our original popular Exploring Java. With each edition we've taken great care not only to add new material covering additional features, but to thoroughly revise and update the existing content to synthesize the coverage and add years of real world perspective and experience to these pages. One noticeable change in recent editions is that we've deemphasized the use of applets, reflecting their somewhat static role over the past couple of years in creating interactive web pages. And in this edition we've greatly expanded our coverage of web applications and services, which are now mature technologies. We've also included a chapter on working with XML and XSL, which are important new technologies.

We cover the most interesting features of Sun's newest release of Java, officially called Java 2 Standard Edition SDK Version 1.4 . (In the old days, it would have been called JDK for Java Development Kit; Sun now uses the term SDK for Software Development Kit.) Sun coined the term "Java 2" to cover the major new features introduced in Java Version 1.2. When it's necessary to mention versions, we'll simply refer to them as Java 1.x. New features in Java 1.4 include important improvements for servlets and web applications, regular expressions, Swing enhancements, new language features such as assertions and chained exceptions, logging and preferences APIs and a completely new I/O facility. Another important change in recent Java history (Version 1.2) was the ascendancy of Java Swing as the main API for graphical user interface programming. All the material in this book relating to AWT, Java's original GUI programming interface, has been recast and updated in terms of the Swing facilities.