More Java Pitfalls 50 New Time-Saving Solutions and Workarounds

477 Pages·2003·3.879 MB·English

by  Michael C. Daconta, Kevin T. Smith, Donald Avondolio, W. Clay Richardson

More Java™ Pitfalls
50 New Time-Saving
Solutions and Workarounds

More Java™ Pitfalls
50 New Time-Saving
Solutions and Workarounds
Michael C. Daconta
Kevin T. Smith
Donald Avondolio
W. Clay Richardson
Publisher: Joe Wikert
Executive Editor: Robert M. Elliott
Assistant Developmental Editor: Emilie Herman
Managing Editor: Micheline Frederick
New Media Editor: Angela Denny
Text Design & Composition: Wiley Composition Services
This book is printed on acid-free paper. ∞
Copyright 2003 by Michael C. Daconta, Kevin T. Smith, Donald Avondolio, and W. Clay
Richardson. All rights reserved.
Published by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
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Library of Congress Cataloging-in-Publication Data:
ISBN: 0-471-23751-5
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
This book is dedicated to the memory of Edsger W. Dijkstra who said,
“I mean, if 10 years from now, when you are doing something quick and
dirty, you suddenly visualize that I am looking over your shoulders and
say to yourself, ‘Dijkstra would not have liked this’, well that would be
enough immortality for me.”
We humbly disagree: 10 years of Dijkstra is just not long enough; may
he happily haunt our consciousness for 1010 years. Such an increase is
more befitting his stature.

Contents
Introduction xi
Acknowledgments xvii
Part One The Client Tier 1
Item 1: When Runtime.exec() Won’t 4
Item 2: NIO Performance and Pitfalls 17
Canonical File Copy 20
Little-Endian Byte Operations 21
Non-Blocking Server IO 26
Item 3: I Prefer Not to Use Properties 34
Item 4: When Information Hiding Hides Too Much 39
Item 5: Avoiding Granularity Pitfalls In java.util.logging 44
Item 6: When Implementations of Standard APIs Collide 53
Item 7: My Assertions are Not Gratuitous! 59
How to Use Assertions 59
Item 8: The Wrong Way to Search a DOM 66
Item 9: The Saving-a-DOM Dilemma 73
Item 10: Mouse Button Portability 80
Item 11: Apache Ant and Lifecycle Management 88
Item 12: JUnit: Unit Testing Made Simple 100
vii
viii Contents
Item 13: The Failure to Execute 108
Deploying Java Applications 109
The Java Extension Mechanism 110
Sealed Packages 111
Security 112
Item 14: What Do You Collect? 112
Item 15: Avoiding Singleton Pitfalls 117
When Multiple Singletons in Your VM Happen 119
When Singletons are Used as Global Variables, or Become
Non-Singletons 120
Item 16: When setSize() Won’t Work 122
Item 17: When Posting to a URL Won’t 126
Connecting via HTTPwith the java.net Classes 126
An Alternative Open Source HTTPClient 137
Item 18: Effective String Tokenizing 140
Item 19: JLayered Pane Pitfalls 146
Item 20: When File.renameTo() Won’t 151
Item 21: Use Iteration over Enumeration 157
Item 22: J2ME Performance and Pitfalls 162
Part Two The Web Tier 199
Item 23: Cache, It’s Money 200
Item 24: JSP Design Errors 208
Request/Response Paradigm 208
Maintaining State 209
JSPthe Old Way 210
JSPDevelopment with Beans (Model 1 Architecture) 214
JSPDevelopment in the Model 2 Architecture 220
Item 25: When Servlet HttpSessions Collide 220
Item 26: When Applets Go Bad 227
Item 27: Transactional LDAP—Don’t Make that Commitment 235
Item 28: Problems with Filters 244
Item 29: Some Direction about JSP Reuse and Content Delivery 255
Item 30: Form Validation Using Regular Expressions 261