Sams Teach Yourself Java 6 in 21 Days, 5th Edition

721 Pages·2007·6.279 MB·English

by  Rogers Cadenhead, Laura Lemay

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Rogers Cadenhead
Laura Lemay
SamsTeachYourself
Java 6
™
in 21 Days
800 East 96th Street,Indianapolis,Indiana 46240
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Library of Congress Cataloging-in-Publication Data
Cadenhead, Rogers.
Sams teach yourself Java 6 in 21 days / Rogers Cadenhead, Laura Lemay.
p. cm.
Includes index.
ISBN 978-0-672-32943-2 (pbk. w/cd)
1. Java (Computer program language) I. Lemay, Laura. II. Title.
QA76.73.J38C333 2007
005.13'3--dc22
2007014568
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Contents at a Glance
Introduction 1
WEEK I: The Java Language
1 Getting Started with Java 9
2 The ABCs of Programming 35
3 Working with Objects 63
4 Lists,Logic,and Loops 89
5 Creating Classes and Methods 115
6 Packages,Interfaces,and Other Class Features 145
7 Exceptions,Assertions,and Threads 183
WEEK II: The Java Class Library
8 Data Structures 219
9 Working with Swing 247
10 Building a Swing Interface 273
11 Arranging Components on a User Interface 303
12 Responding to User Input 333
13 Using Color,Fonts,and Graphics 357
14 Developing Swing Applications 381
WEEK III: Java Programming
15 Working with Input and Output 405
16 Serializing and Examining Objects 433
17 Communicating Across the Internet 453
18 Accessing Databases with JDBC 485
19 Reading and Writing RSS Feeds 511
20 XML Web Services 535
21 Writing Java Servlets and Java Server Pages 555
Appendixes
A Using the Java Development Kit 601
B Programming with the Java Development Kit 625
C This Book’s Web Site 649
Index 651
Bonus Material on the Companion CD-ROM
CD1 Choosing Java
CD2 Writing Java Applets
CD3 Regular Expressions
CD4 Where to Go from Here: Java Resources
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Table of Contents
Introduction 1
How This Book Is Organized ..................................................................................2
Who Should Read This Book ..................................................................................4
Conventions Used in This Book ..............................................................................5
WEEK I: The Java Language
DAY 1: Getting Started with Java 9
The Java Language ..............................................................................................10
History of the Language ..............................................................................10
Introduction to Java ....................................................................................11
Selecting a Development Tool ......................................................................11
Object-Oriented Programming................................................................................12
Objects and Classes..............................................................................................14
Attributes and Behavior........................................................................................17
Attributes of a Class of Objects ....................................................................17
Behavior of a Class of Objects......................................................................18
Creating a Class..........................................................................................19
Running the Program ..................................................................................21
Organizing Classes and Class Behavior....................................................................24
Inheritance ................................................................................................24
Creating a Class Hierarchy ..........................................................................26
Inheritance in Action ..................................................................................28
Single and Multiple Inheritance ....................................................................29
Interfaces ..................................................................................................30
Packages ..................................................................................................30
Summary............................................................................................................31
Q&A ................................................................................................................31
Quiz..................................................................................................................32
Questions..................................................................................................32
Answers....................................................................................................32
Certification Practice ..................................................................................32
Exercises............................................................................................................33
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DAY 2: The ABCs of Programming 35
Statements and Expressions ..................................................................................36
Variables and Data Types......................................................................................36
Creating Variables ......................................................................................37
Naming Variables........................................................................................39
Variable Types............................................................................................39
Assigning Values to Variables........................................................................41
Constants..................................................................................................41
Comments..........................................................................................................43
Literals..............................................................................................................44
Number Literals..........................................................................................45
Boolean Literals..........................................................................................46
Character Literals........................................................................................46
String Literals............................................................................................47
Expressions and Operators ....................................................................................48
Arithmetic ................................................................................................49
More About Assignment..............................................................................51
Incrementing and Decrementing....................................................................52
Comparisons..............................................................................................53
Logical Operators ......................................................................................54
Operator Precedence....................................................................................55
String Arithmetic ................................................................................................57
Summary............................................................................................................58
Q&A ................................................................................................................59
Quiz..................................................................................................................60
Questions..................................................................................................60
Answers....................................................................................................60
Certification Practice ..................................................................................60
Exercises............................................................................................................61
DAY 3: Working with Objects 63
Creating New Objects ..........................................................................................64
Usingnew..................................................................................................64
WhatnewDoes ..........................................................................................66
A Note on Memory Management ..................................................................66
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vi Sams Teach Yourself Java 6 in 21 Days
Accessing and Setting Class and Instance Variables....................................................67
Getting Values............................................................................................67
Changing Values ........................................................................................68
Class Variables ..........................................................................................69
Calling Methods..................................................................................................70
Nesting Method Calls..................................................................................72
Class Methods............................................................................................73
References to Objects ..........................................................................................74
Casting and Converting Objects and Primitive Types..................................................76
Casting Primitive Types................................................................................77
Casting Objects..........................................................................................78
Converting Primitive Types to Objects and Vice Versa ......................................80
Comparing Object Values and Classes ....................................................................82
Comparing Objects......................................................................................82
Determining the Class of an Object................................................................84
Summary............................................................................................................84
Q&A ................................................................................................................85
Quiz..................................................................................................................86
Questions..................................................................................................86
Answers....................................................................................................86
Certification Practice ..................................................................................86
Exercises............................................................................................................87
DAY 4: Lists,Logic,and Loops 89
Arrays................................................................................................................90
Declaring Array Variables............................................................................90
Creating Array Objects................................................................................91
Accessing Array Elements............................................................................92
Changing Array Elements ............................................................................93
Multidimensional Arrays..............................................................................95
Block Statements ................................................................................................96
ifConditionals ..................................................................................................97
switchConditionals ............................................................................................98
forLoops ........................................................................................................104
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Contents vii
whileanddoLoops ..........................................................................................107
whileLoops............................................................................................107
do-whileLoops ......................................................................................109
Breaking Out of Loops........................................................................................109
Labeled Loops..........................................................................................110
The Conditional Operator ..........................................................................110
Summary..........................................................................................................112
Q&A................................................................................................................112
Quiz................................................................................................................112
Questions ................................................................................................112
Answers..................................................................................................113
Certification Practice..................................................................................113
Exercises..........................................................................................................114
DAY 5: Creating Classes and Methods 115
Defining Classes................................................................................................116
Creating Instance and Class Variables....................................................................116
Defining Instance Variables ........................................................................116
Class Variables..........................................................................................117
Creating Methods ..............................................................................................117
Defining Methods......................................................................................118
ThethisKeyword....................................................................................120
Variable Scope and Method Definitions ........................................................121
Passing Arguments to Methods....................................................................122
Class Methods..........................................................................................123
Creating Java Applications ..................................................................................124
Helper Classes..........................................................................................125
Java Applications and Command-line Arguments ....................................................126
Passing Arguments to Java Applications........................................................126
Handling Arguments in Your Java Application................................................127
Creating Methods with the Same Name, Different Arguments....................................128
Constructor Methods ..........................................................................................132
Basic Constructor Methods ........................................................................133
Calling Another Constructor Method............................................................133
Overloading Constructor Methods................................................................134
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viii Sams Teach Yourself Java 6 in 21 Days
Overriding Methods............................................................................................136
Creating Methods That Override Existing Methods..........................................136
Calling the Original Method........................................................................137
Overriding Constructors..............................................................................138
Finalizer Methods..............................................................................................140
Summary..........................................................................................................141
Q&A................................................................................................................141
Quiz................................................................................................................142
Questions ................................................................................................142
Answers..................................................................................................143
Certification Practice..................................................................................143
Exercises..........................................................................................................144
DAY 6: Packages,Interfaces,and Other Class Features 145
Modifiers..........................................................................................................146
Access Control for Methods and Variables ....................................................146
Static Variables and Methods................................................................................152
Final Classes, Methods, and Variables....................................................................154
Variables..................................................................................................155
Methods..................................................................................................155
Classes....................................................................................................156
Abstract Classes and Methods..............................................................................156
Packages..........................................................................................................157
Using Packages..................................................................................................157
Full Package and Class Names ....................................................................158
TheimportDeclaration ............................................................................159
Class Name Conflicts ................................................................................160
A Note About Classpathand Where Classes Are Located ..............................161
Creating Your Own Packages ..............................................................................162
Picking a Package Name ............................................................................162
Creating the Folder Structure ......................................................................162
Adding a Class to a Package........................................................................163
Packages and Class Access Control..............................................................163
Interfaces..........................................................................................................164
The Problem of Single Inheritance................................................................164
Interfaces and Classes................................................................................164
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Contents ix
Implementing and Using Interfaces ..............................................................165
Implementing Multiple Interfaces ................................................................165
Other Uses of Interfaces ............................................................................166
Creating and Extending Interfaces ........................................................................166
New Interfaces..........................................................................................166
Methods Inside Interfaces ..........................................................................167
Extending Interfaces..................................................................................168
Creating an Online Storefront......................................................................169
Inner Classes ....................................................................................................175
Summary..........................................................................................................177
Q&A................................................................................................................178
Quiz................................................................................................................179
Questions ................................................................................................179
Answers..................................................................................................179
Certification Practice..................................................................................179
Exercises..........................................................................................................181
DAY 7: Exceptions,Assertions,and Threads 183
Exceptions........................................................................................................184
Exception Classes......................................................................................186
Managing Exceptions..........................................................................................187
Exception Consistency Checking..................................................................188
Protecting Code and Catching Exceptions......................................................188
ThefinallyClause..................................................................................190
Declaring Methods That Might Throw Exceptions....................................................193
ThethrowsClause....................................................................................193
Which Exceptions Should You Throw?..........................................................194
Passing On Exceptions ..............................................................................195
throwsand Inheritance..............................................................................196
Creating and Throwing Your Own Exceptions ........................................................197
Throwing Exceptions ................................................................................197
Creating Your Own Exceptions....................................................................198
Combiningthrows,try, and throw..............................................................199
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