This book's primary objective is to help you prepare for and pass Sun Microsystem's SCJP certification for Java 6 or Java 5. The Java 6 and Java 5 exams are almost identical in scope, and they are both much broader than their predecessor, the Java 1.4 exam. For the remainder of this book we'll typically reference the Java 6 exam, but remember that other than the addition of the System.Console class and Navigable collections, the Java 5 and Java 6 exams are identical in scope. We recommend that you take the Java 6 exam and not the Java 5 exam, but if you do decide to take the Java 5 exam, this book is still appropriate. The new exam's objectives touch on many of the more commonly used of Java's APIs. The key word here is "touch." The exam's creators intended that passing the exam will demonstrate that the candidate understands the basicsof APIs such as those for file I/O and regular expressions. This book follows closely both the breadth and the depth of the real exam. For instance, after reading this book, you probably won't emerge as a regex guru, but if you study the material, and do well on the self tests, you'll have a basic understanding of regex, and you'll do well on the exam. After completing this book, you should feel confident that you have thoroughly reviewed all of the objectives that Sun has established for the exam.