Sams teach yourself Java 2 in 21 days

841 Pages·5.697 MB·English

by  Cadenhead, Rogers;Lemay, Laura

Rogers Cadenhead
Laura Lemay
Teach Yourself
Java 2
21
in Days
FOURTH EDITION
800 East 96th Street, Indianapolis, Indiana, 46240 USA
Sams Teach Yourself Java 2 in 21 Days, ACQUISITIONSEDITOR
Scott Meyers
Fourth Edition
MANAGINGEDITOR
Copyright ©2004 by Sams Publishing Charlotte Clapp
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for damages resulting from the use of the information contained herein. Chris Barrick
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Library of Congress Catalog Number:2003110452
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Printed in the United States of America
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First Printing:May 2004
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Contents at a Glance
Introduction 1
WEEK 1 The Java Language 7
Day 1 Getting Started with Java 9
2 The ABCs of Programming 35
3 Working with Objects 63
4 Lists,Logic,and Loops 87
5 Creating Classes and Methods 113
6 Packages,Interfaces,and Other Class Features 143
7 Threads,Exceptions,and Assertions 181
WEEK 2 The Java Class Library 215
Day 8 Data Structures 217
9 Working with Swing 245
10 Building a Swing Interface 271
11 Arranging Components on a User Interface 299
12 Responding to User Input 329
13 Using Color,Fonts,and Graphics 351
14 Writing Java Applets and Java Web Start Applications 375
WEEK 3 Java Programming 411
Day 15 Working with Input and Output 413
16 Serializing and Examining Objects 441
17 Communicating Across the Internet 469
18 JavaSound 501
19 Creating and Using JavaBeans 521
20 Reading and Writing Data Using JDBC and XML 543
21 Writing Java Servlets and JavaServer Pages 585
Appendixes 629
Appendix A Choosing Java 631
B Using the Java Development Kit 643
C Programming with the Java Development Kit 667
D Using the NetBeans Integrated Development Environment 689
E Writing Java 1.1 Applets 699
F Creating Web Services with XML-RPC 721
G Regular Expressions 739
H Where to Go from Here:Java Resources 753
I The Book’s Web Site 759
Index 761
Contents
Introduction 1
WEEK 1 The Java Language 7
DAY 1 Getting Started with Java 9
The Java Language ..............................................................................................10
History of the Language ..................................................................................10
Introduction to Java ........................................................................................11
Selecting a Development Tool ........................................................................12
Object-Oriented Programming ............................................................................13
Objects and Classes ..............................................................................................15
Object Reuse ....................................................................................................16
Attributes and Behavior ........................................................................................17
Attributes of a Class of Objects ......................................................................18
Behavior of a Class of Objects ........................................................................19
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 ..........................................................................................................31
Summary ..............................................................................................................31
Q&A ......................................................................................................................33
Quiz ......................................................................................................................33
Questions ........................................................................................................33
Answers ..........................................................................................................34
Certification Practice ......................................................................................34
Exercises ..............................................................................................................34
DAY 2 The ABCs of Programming 35
Statements and Expressions ..................................................................................36
Variables and Data Types ......................................................................................37
Creating Variables ............................................................................................38
Naming Variables ............................................................................................39
Variable Types ................................................................................................40
Assigning Values to Variables ........................................................................42
Constants ........................................................................................................42
Comments ............................................................................................................44
Literals ..................................................................................................................45
Number Literals ..............................................................................................45
Boolean Literals ..............................................................................................46
Character Literals ............................................................................................47
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 ......................................................................................61
Exercises ..............................................................................................................61
DAY 3 Working with Objects 63
Creating New Objects ..........................................................................................63
Usingnew ........................................................................................................64
WhatnewDoes ................................................................................................66
A Note on Memory Management ..................................................................66
Accessing and Setting Class and Instance Variables ............................................67
Getting Values ..................................................................................................67
Changing Values ..............................................................................................68
Class Variables ................................................................................................69
Calling Methods ....................................................................................................70
Nesting Method Calls ......................................................................................71
Class Methods ................................................................................................72
References to Objects ..........................................................................................73
Casting and Converting Objects and Primitive Types ..........................................75
Casting Primitive Types ..................................................................................76
Casting Objects ................................................................................................77
Converting Primitive Types to Objects and Vice Versa ..................................78
Comparing Object Values and Classes ................................................................80
Comparing Objects ..........................................................................................81
Determining the Class of an Object ................................................................82
Summary ..............................................................................................................83
Q&A ......................................................................................................................83
Quiz ......................................................................................................................84
Questions ........................................................................................................84
Answers ..........................................................................................................85
Certification Practice ......................................................................................85
Exercises ..............................................................................................................86
vi Sams Teach Yourself Java 2 in 21 Days
DAY 4 Lists, Logic, and Loops 87
Arrays ....................................................................................................................87
Declaring Array Variables ..............................................................................88
Creating Array Objects ....................................................................................89
Accessing Array Elements ..............................................................................90
Changing Array Elements ..............................................................................91
Multidimensional Arrays ................................................................................93
Block Statements ..................................................................................................94
ifConditionals ....................................................................................................95
switchConditionals ..............................................................................................97
forLoops ............................................................................................................102
whileanddoLoops ............................................................................................105
whileLoops ..................................................................................................105
do-whileLoops ............................................................................................107
Breaking Out of Loops ......................................................................................107
Labeled Loops ..............................................................................................108
The Conditional Operator ..............................................................................109
Summary ............................................................................................................110
Q&A ....................................................................................................................110
Quiz ....................................................................................................................111
Questions ......................................................................................................111
Answers ........................................................................................................111
Certification Practice ....................................................................................111
Exercises ............................................................................................................112
DAY 5 Creating Classes and Methods 113
Defining Classes ................................................................................................114
Creating Instance and Class Variables ................................................................114
Defining Instance Variables ..........................................................................114
Class Variables ..............................................................................................115
Creating Methods ................................................................................................116
Defining Methods ..........................................................................................116
ThethisKeyword ........................................................................................118
Variable Scope and Method Definitions ......................................................119
Passing Arguments to Methods ....................................................................120
Class Methods ..............................................................................................121
Creating Java Applications ................................................................................122
Helper Classes ..............................................................................................123
Java Applications and Command-Line Arguments ............................................124
Passing Arguments to Java Applications ......................................................124
Handling Arguments in Your Java Application ............................................125
Creating Methods with the Same Name,Different Arguments ........................126
Constructor Methods ..........................................................................................130
Basic Constructor Methods ..........................................................................131
Calling Another Constructor Method ............................................................131
Overloading Constructor Methods ................................................................132
Contents vii
Overriding Methods ............................................................................................134
Creating Methods That Override Existing Methods ....................................134
Calling the Original Method ........................................................................135
Overriding Constructors ................................................................................136
Finalizer Methods ..............................................................................................138
Summary ............................................................................................................139
Q&A ....................................................................................................................139
Quiz ....................................................................................................................140
Questions ......................................................................................................140
Answers ........................................................................................................141
Certification Practice ....................................................................................141
Exercises ............................................................................................................142
DAY 6 Packages, Interfaces, and Other Class Features 143
Modifiers ............................................................................................................144
Access Control for Methods and Variables ..................................................145
Static Variables and Methods ..............................................................................150
Final Classes,Methods,and Variables ..............................................................152
Variables ........................................................................................................153
Methods ........................................................................................................153
Classes ..........................................................................................................154
Abstract Classes and Methods ............................................................................154
Packages ..............................................................................................................155
Using Packages ..................................................................................................156
Full Package and Class Names ....................................................................156
TheimportDeclaration ................................................................................157
Class Name Conflicts ....................................................................................159
A Note About Classpathand Where Classes Are Located ..........................159
Creating Your Own Packages ............................................................................160
Picking a Package Name ..............................................................................160
Creating the Folder Structure ........................................................................161
Adding a Class to a Package ........................................................................161
Packages and Class Access Control ..............................................................161
Interfaces ............................................................................................................162
The Problem of Single Inheritance ..............................................................162
Interfaces and Classes ..................................................................................163
Implementing and Using Interfaces ..............................................................163
Implementing Multiple Interfaces ................................................................164
Other Uses of Interfaces ................................................................................164
Creating and Extending Interfaces ....................................................................165
New Interfaces ..............................................................................................165
Methods Inside Interfaces ............................................................................166
Extending Interfaces ......................................................................................166
Creating an Online Storefront ......................................................................167
Inner Classes ......................................................................................................173
Summary ............................................................................................................176
Q&A ....................................................................................................................176
viii Sams Teach Yourself Java 2 in 21 Days
Quiz ....................................................................................................................177
Questions ......................................................................................................177
Answers ........................................................................................................177
Certification Practice ....................................................................................178
Exercises ............................................................................................................179
DAY 7 Threads, Exceptions, and Assertions 181
Exceptions ..........................................................................................................182
Exception Classes ..........................................................................................184
Managing Exceptions ........................................................................................185
Exception Consistency Checking ..................................................................185
Protecting Code and Catching Exceptions ....................................................186
ThefinallyClause ......................................................................................188
Declaring Methods That Might Throw Exceptions ............................................190
ThethrowsClause ........................................................................................191
Which Exceptions Should You Throw? ........................................................192
Passing On Exceptions ..................................................................................192
throws and Inheritance ..................................................................................194
Creating and Throwing Your Own Exceptions ..................................................194
Throwing Exceptions ....................................................................................195
Creating Your Own Exceptions ....................................................................195
Combiningthrows,try,andthrow ..............................................................196
When and When Not to Use Exceptions ............................................................197
When to Use Exceptions ..............................................................................197
When Not to Use Exceptions ........................................................................197
Bad Style Using Exceptions ..........................................................................198
Assertions ............................................................................................................199
Threads ................................................................................................................202
Writing a Threaded Program ........................................................................202
A Threaded Application ................................................................................204
Stopping a Thread ........................................................................................208
Summary ............................................................................................................209
Q&A ....................................................................................................................210
Quiz ....................................................................................................................211
Questions ......................................................................................................211
Answers ........................................................................................................211
Certification Practice ....................................................................................212
Exercises ............................................................................................................212
WEEK 2 The Java Class Library 215
DAY 8 Data Structures 217
Data Structures ....................................................................................................217
Java Data Structures ............................................................................................218
Iterator ........................................................................................................219
Bit Sets ..........................................................................................................221
Vectors ..........................................................................................................224
Looping Through Data Structures ................................................................227
Contents ix
Stacks ............................................................................................................230
Map ................................................................................................................231
Hashtables ......................................................................................................233
Generics ..............................................................................................................238
Summary ............................................................................................................241
Q&A ....................................................................................................................241
Quiz ....................................................................................................................242
Questions ......................................................................................................242
Answers ........................................................................................................242
Certification Practice ....................................................................................243
Exercises ............................................................................................................244
DAY 9 Working with Swing 245
Creating an Application ......................................................................................246
Creating an Interface ....................................................................................247
Developing a Framework ..............................................................................249
Creating a Component ..................................................................................251
Adding Components to a Container ..............................................................252
Working with Components ................................................................................253
Image Icons ..................................................................................................254
Labels ............................................................................................................256
Text Fields ....................................................................................................257
Text Areas ......................................................................................................258
Scrolling Panes ..............................................................................................259
Check Boxes and Radio Buttons ..................................................................261
Combo Boxes ................................................................................................263
Lists ....................................................................................................................265
Summary ............................................................................................................266
Q&A ....................................................................................................................267
Quiz ....................................................................................................................268
Questions ......................................................................................................268
Answers ........................................................................................................269
Certification Practice ....................................................................................269
Exercises ............................................................................................................270
DAY 10 Building a Swing Interface 271
Swing Features ....................................................................................................272
Setting the Look and Feel ............................................................................272
Standard Dialog Boxes ..................................................................................275
Using Dialog Boxes ......................................................................................279
Sliders ............................................................................................................282
Scroll Panes ..................................................................................................284
Toolbars ........................................................................................................285
Progress Bars ................................................................................................288
Menus ............................................................................................................290
Tabbed Panes ................................................................................................294
Summary ............................................................................................................295
Q&A ....................................................................................................................295