9780471361749

A lifesaver for any Java programmer-proven workarounds and time-saving solutions Although using the Java language provides a substantial boost to a programmer's productivity, it still has its share of subtleties andweaknesses. This book is designed to save you time and frustration by carefully guiding you through this potential minefield. A team of Java experts, led by programming guru Michael Daconta, offers a collection of proven solutions to 50 difficult, real-world problems chosen from their own extensive experiences. You'll find workarounds for problems caused by shortcomings in both the Java language itself and in its APIs and utilities, including java.util, java.io, java.awt, and javax.swing. The authors also share techniques for improving the performance of your Java applications. For easy reference, the book is organized into categories so that similar solutions are grouped together. Examples of topics covered include: * Language syntax, for example, using the String equals( ) method instead of the == operator (Item2) * Language support, for example, method dispatching with reflection, interfaces, and anonymous classes (Item 16) * Utilities and collections, like choosing between a PropertyFile and ResourceBundle (Item 20) * Input/output, including subtleties in sending serialized objects over a network (Item 25) * GUI presentation, for example, tackling the common pitfall of using repaint( ) instead of validate( ) for relaying out components (Item 29) * Performance, including tips like lazy loading your way to better performance (Item 43)

MICHAEL C. DACONTA is President of Synergy Solutions, Inc., where he conducts training seminars and develops advanced systems with Java, JavaScript, and XML. He is a Sun-certified Java programmer and author of Java 2 and JavaScript for C and C++ Programmers and C++ Pointers and Dynamic Memory Management.

Acknowledgments

ix

Introduction

xi

PART ONE LANGUAGE SYNTAX

1

(38)

When Is an ``Overridden'' Method Not Really Overridden?

2

(3)

Usage of String equals() Method versus the ``=='' Operator

5

(3)

Java Is Strongly Typed

8

(4)

Type Conversion

9

(1)

Widening

9

(1)

Narrowing

10

(1)

Implicit Type Conversion

11

(1)

Is That a Constructor?

12

(2)

Cannot Access Overridden Methods

14

(3)

Avoid the ``Hidden Field'' Pitfall

17

(8)

Kinds of Java Variables

18

(1)

Variable Scope

19

(1)

Which Kinds of Variables Can Be Hidden?

20

(1)

How Instance Variables and Class Variables Get Hidden

20

(2)

How to Access a Hidden Field Member

22

(1)

How Hidden Variables Differ from an Overridden Method

23

(2)

Forward References

25

(1)

Design Constructors for Extension

26

(7)

Passing Primitives by Reference

33

(3)

Boolean Logic and Short-Circuit Operators

36

(3)

PART TWO LANGUAGE SUPPORT

39

(52)

Reclaiming References When Using SoftReference Objects

40

(10)

A Word about Garbage Collection

40

(2)

The SoftReference Class

42

(6)

Reference Queues

48

(2)

Causing Deadlock by Calling a Synchronized Method from a Synchronized Method

50

(10)

Review of Threads, Monitors, and the ``Synchronized'' Keyword

51

(4)

Example of Deadlock Scenario

55

(5)

Properly Cloning an Object

60

(6)

Overriding the equals Method

66

(4)

Using StringBuffer Objects as Hashmap Keys

68

(2)

Avoid Using Constructor for Implementing clone()

70

(5)

Method Dispatching with Reflection, Interfaces, and Anonymous Classes

75

(10)

Handling Exceptions and OutOfMemoryError

85

(6)

Exception Syntax

86

(1)

Exception Hierarchy

86

(1)

Catching Exceptions

87

(1)

Running Out of Memory

88

(3)

PART THREE UTILITIES AND COLLECTIONS

91

(30)

Ordered Property Keys?

92

(4)

Handling Occasionally Huge Collections with Caching and Persistence

96

(12)

Property File or ResourceBundle?

108

(3)

Properties Object Pitfalls

111

(6)

Using Vector as a Collection Instead of Old API

117

(4)

PART FOUR INPUT/OUTPUT

121

(24)

Serialization

122

(4)

What Really Happens When We Serialize an Object?

123

(1)

The Externalizable Interface

124

(2)

Unicode, UTF, and Streams

126

(6)

Unicode

126

(1)

UTF

127

(1)

Streams

128

(3)

Input or Output

128

(1)

Bytes or Characters

129

(1)

Low Level or High Level

130

(1)

Data Sink or Filter

130

(1)

Chaining

130

(1)

Configurable Encoding

131

(1)

Sending Serialized Objects over Sockets

132

(3)

Try, Catch ... Finally?

135

(4)

Flushing Image Resources

139

(6)

PART FIVE GUI PRESENTATION

145

(52)

Providing Progress Feedback

146

(6)

Using a Busy Cursor

147

(2)

Using a Progress Monitor

149

(3)

Using repaint() Instead of validate() for Re-Layout of Components

152

(4)

Z-Order and Overlapping Components

156

(8)

Layout Managers

157

(5)

JLayeredPane

162

(2)

Solving the Validate, Revalidate, Invalidate Mystery

164

(4)

Stacking Items Vertically

168

(10)

How to Use GridBagLayout Properly

178

(8)

Avoiding Flicker

186

(6)

Painting in AWT

187

(4)

Painting in Swing

191

(1)

Components with Embedded HTML

192

(5)

PART SIX GUI CONTROL

197

(68)

Better Data Validation

198

(11)

Tailored Components

199

(1)

Filtering

199

(1)

Consuming Events

200

(1)

Post-Entry Validation

201

(1)

Design Issues

202

(1)

Asynchronous Validation

202

(2)

Validation Adapter

204

(2)

Validation Techniques

206

(1)

Validation Using Exceptions

206

(2)

Chained Validators

208

(1)

End Notes

209

(1)

Desensitizing GUI Components Based on Application State

209

(7)

The Over-Reactive Approach

210

(1)

The Brute-Force Approach

210

(1)

The Abstract Approach---A StateMonitor Class

211

(2)

List Viewer

213

(2)

Adaptive Sensitization

215

(1)

Use Threads in Event Handlers to Avoid Freezing Your GUI

216

(8)

Implementing an Effective Cancel with Threading

218

(4)

Implementing an Effective Cancel with SwingWorker

222

(2)

Model View Controller and JTree

224

(3)

How to Data Transfer Something Other Than Text

227

(23)

Data Transfer Overview

227

(2)

Three Types of Data Transfer

229

(1)

Intra-JVM Example

229

(5)

Determining What Support Is Available for Data Transfer

234

(1)

Inter-JVM and Native-JVM Example

235

(15)

A KeyListener That Doesn't Listen?

250

(4)

Printing Text, HTML, and Images in a JEditorPane

254

(11)

PART SEVEN PERFORMANCE

265

(24)

Lazy Loading Our Way to Better Performance

266

(3)

Using Object Pools for Excessive Object Creation

269

(5)

Object Recycling

269

(1)

A Comparison to Caching

269

(1)

Implementation

270

(2)

The Good

272

(1)

The Bad

272

(1)

The Ugly

273

(1)

Performance Watch: Array versus Vector

274

(6)

Why is a Vector so much slower than an Array?

277

(1)

When should I use a Vector?

278

(1)

The ArrayList Class

279

(1)

Avoid Using Temporary Arrays for Dynamic Array Growth

280

(6)

Use StringBuffer Instead of `+' for Concatenation inside a Loop

286

(3)

PART EIGHT MISCELLANEOUS

289

(26)

Is There a Better Way to Debug?

290

(2)

Encapsulating JNI Calls through Interfaces

292

(15)

Discussion of Concept

292

(2)

An Example Interface

294

(2)

Pure Java Implementation

296

(2)

Native Implementation

298

(4)

Windows Specifics

302

(5)

Assertions

307

(8)

Assertions in Java

308

(1)

Using Assertions

308

(1)

How Not to Use Assertions

309

(1)

Sample Implementation

310

(5)

Index

315

What is included with this book?

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.