TeAM YYePG Digitally signed by TeAM YYePG DN: cn=TeAM YYePG, c=US, o=TeAM YYePG, ou=TeAM YYePG, email=yyepg@msn.com Reason: I attest to the accuracy and integrity of this document Date: 2005.02.24 07:33:04 +08'00' Ivor Horton’s Beginning Java™ 2, JDK™ Edition Ivor Horton’s Beginning Java™ 2, JDK™ Edition Ivor Horton Ivor Horton’s Beginning Java™ 2, JDK™ Edition Published by Wiley Publishing, Inc 10475 Crosspoint Boulevard Indianapolis, IN 46256 www.wiley.com Copyright © 2005 by Ivor Horton Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada ISBN: 0-7645-6874-4 Manufactured in the United States of America 10 5B/RU/RS/QU/IN No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600 Requests to the Publisher for permission should be addressed to the Legal Department, Wiley Publishing, Inc., 10475 Crosspoint Blvd., Indianapolis, IN 46256, (317) 572-3447, fax (317) 572-4355, e-mail: brandreview@wiley.com LIMIT OF LIABILITY/DISCLAIMER OF WARRANTY: THE PUBLISHER AND THE AUTHOR MAKE NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES, INCLUDING WITHOUT LIMITATION WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE NO WARRANTY MAY BE CREATED OR EXTENDED BY SALES OR PROMOTIONAL MATERIALS THE ADVICE AND STRATEGIES CONTAINED HEREIN MAY NOT BE SUITABLE FOR EVERY SITUATION THIS WORK IS SOLD WITH THE UNDERSTANDING THAT THE PUBLISHER IS NOT ENGAGED IN RENDERING LEGAL, ACCOUNTING, OR OTHER PROFESSIONAL SERVICES IF PROFESSIONAL ASSISTANCE IS REQUIRED, THE SERVICES OF A COMPETENT PROFESSIONAL PERSON SHOULD BE SOUGHT NEITHER THE PUBLISHER NOR THE AUTHOR SHALL BE LIABLE FOR DAMAGES ARISING HEREFROM THE FACT THAT AN ORGANIZATION OR WEBSITE IS REFERRED TO IN THIS WORK AS A CITATION AND/OR A POTENTIAL SOURCE OF FURTHER INFORMATION DOES NOT MEAN THAT THE AUTHOR OR THE PUBLISHER ENDORSES THE INFORMATION THE ORGANIZATION OR WEBSITE MAY PROVIDE OR RECOMMENDATIONS IT MAY MAKE FURTHER, READERS SHOULD BE AWARE THAT INTERNET WEBSITES LISTED IN THIS WORK MAY HAVE CHANGED OR DISAPPEARED BETWEEN WHEN THIS WORK WAS WRITTEN AND WHEN IT IS READ For general information on our other products and services or to obtain technical support, please contact our Customer Care Department within the U.S at (800) 762-2974, outside the U.S at (317) 572-3993 or fax (317) 572-4002 For technical support, please visit www.wiley.com/techsupport Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books Library of Congress Cataloging-in-Publication Data Horton, Ivor Ivor Horton’s Beginning Java 2, JDK Edition / Ivor Horton p cm Includes index ISBN 0-7645-6874-4 (paper/website) Java (Computer program language) I Title: Ivor Horton’s Beginning Java 2, JDK Edition II Title QA76.73.J38H6758 2004 005.13’3—dc22 2004017036 Trademarks: Wiley, the Wiley Publishing logo, Wrox, the Wrox logo, Programmer to Programmer, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc and/or its affiliates, in the United States and other countries, and may not be used without written permission Java and JDK are trademarks of Sun Microsystems, Inc All other trademarks are the property of their respective owners Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book About the Author Ivor Horton started out as a mathematician, but shortly after graduating, he was lured into messing about with computers by a well-known manufacturer He has spent many happy years programming occasionally useful applications in a variety of languages as well as teaching mainly scientists and engineers to likewise He has extensive experience in applying computers to problems in engineering design and to manufacturing operations in a wide range of industries He is the author of a number of tutorial books on programming in C, C++, and Java When not writing programming books or providing advice to others, he leads a life of leisure Credits Executive Editor Project Coordinator Robert Elliott Erin Smith Senior Development Editor Graphics and Production Specialists Kevin Kent William A Barton Karl Brandt Jonelle Burns Kelly Emkow Carrie Foster Lauren Goddard Denny Hager Joyce Haughey Jennifer Heleine Ron Terry Copy Editor Quality Control Technicians Luann Rouff Joe Niesen Susan Moritz Brian H Walls Technical Editors Calvin Austin, J2SE 5.0 Specification Lead, Sun Microsystems Wiley-Dreamtech India Pvt Ltd Production Editor Editorial Manager Mary Beth Wakefield Media Development Specialist Vice President & Executive Group Publisher Travis Silvers Richard Swadley Proofreading and Indexing Vice President and Publisher TECHBOOKS Production Services Joseph B Wikert Cover Photograph © Ian Capener Foreword You are probably reading this foreword with one of several things in mind First, is this the right book for me, is the material current, and does the text reflect the final API? Second, what should I expect to learn and where should I start reading a book of this length? Many of the forewords I have seen will lead you through an amusing anecdote or story and then mention a little about the author, but then fail to leave you any wiser about the answer to those questions So, to get straight to the point and to answer the second question first, this is a book that you can start from page one and read right through to the end If you haven’t read any of Ivor Horton’s books before, you are in for a pleasant surprise Ivor’s style is very accessible, which makes the content easy to follow and understand I know, because I have read this book from cover to cover This edition of Ivor Horton’s Beginning Java 2, JDK Edition is based on the J2SE 5.0 platform The J2SE 5.0 release is one of the most significant updates to the Java platform in many years and has been three years in the making The release involved 160 experts worldwide, all working through the Java Community Process and focused on making the platform better for all developers I have been involved with the project since day one as the Specification Lead for JSR 176, which defines the contents of J2SE 5.0 As such, I had a great interest in making sure that this book is accurate and matches the final API set I’ve even compiled and run every code example twice, and there are a lot of great examples, as you will find out So what can you expect to learn from this new edition? First, Ivor covers the basic programming blocks and gets you started with your first Java program Ivor then introduces the Java language changes step by step, including the new generic types, the enhanced for loop, enumerated types, and many others You will also get to use the new language changes in later chapters and learn some of the other nonlanguage features, such as XML DOM3 updates So whether you are a new developer or already have some Java programming experience, you will gain the skills needed to work with the latest Java release In closing, I encourage you to read and enjoy what JDK 5.0 has to offer and find out how easy using J2SE 5.0 really is Calvin Austin J2SE 5.0 Specification Lead Sun Microsystems ... Argument List xviii 24 1 24 2 24 3 24 4 24 6 24 6 24 8 25 0 25 1 25 6 25 7 26 2 26 3 26 4 26 5 26 6 26 6 26 7 26 9 26 9 27 1 27 2 27 3 27 3 27 4 27 5 27 5 27 6 27 7 27 9 27 9 28 2 28 6 28 7 28 8 28 9 28 9 29 1 29 5 29 7 Contents Casting... 5 02 50 7 5 12 51 3 51 7 51 9 51 9 52 3 52 4 52 5 52 5 52 6 52 8 52 9 5 32 53 3 53 3 53 7 53 8 53 8 54 1 Contents Serialization Problems and Complications Resetting an Object Output Stream Summary Exercises 5 42 54 4... of Objects Sets Sequences Maps Hashing 55 5 55 7 55 9 55 9 56 0 56 0 56 1 56 5 56 5 56 7 56 9 57 1 57 9 58 0 5 82 58 4 58 7 58 8 5 92 59 5 59 8 59 9 600 601 601 6 02 603 604 6 05 606 xxiii Contents Iterators List Iterators