Sams Teach Yourself Java in 21 Days (Covering Java 7 and Android)

Rogers Cadenhead is a programmer and author. He has written more than 20 books on programming and web publishing, including Sams Teach Yourself Java in 24 Hours. He also publishes the Drudge Retort and other websites that receive more than 20 million visits a year. He maintains this book’s official website at www.java21days.com and a personal weblog at http://workbench.cadenhead.org.

Introduction   1

WEEK 1: The Java Language   7

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   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   23

Organizing Classes and Class Behavior   25

Inheritance  

Creating a Class Hierarchy   27

Inheritance in Action   29

Interfaces   31

Packages   32

Summary   32

Q&A  

Quiz   34

Questions   34

Certification Practice   34

Exercises   35

2 The ABCs of Programming   37

Statements and Expressions   38

Variables and Data Types   38

Creating Variables   39

Naming Variables   40

Variable Types   41

Assigning Values to Variables   43

Constants   43

Comments   45

Literals   46

Number Literals   47

Boolean Literals   48

Character Literals   49

String Literals   50

Expressions and Operators   51

Arithmetic   51

More About Assignment   53

Incrementing and Decrementing   54

Comparisons   56

Logical Operators   57

Operator Precedence   58

String Arithmetic   60

Summary   61

Q&A   62

Quiz   62

Questions   62

Certification Practice   63

Exercises   63

3 Working with Objects   65

Creating New Objects   66

Using new   66

How Objects Are Constructed   68

A Note on Memory Management   69

Using Class and Instance Variables   70

Getting Values   70

Setting Values   70

Class Variables   72

Calling Methods   73

Formatting Strings   75

Nesting Method Calls   75

Class Methods   76

References to Objects   77

Casting Objects and Primitive Types   79

Casting Primitive Types   80

Casting Objects   81

Converting Primitive Types to Objects and Vice Versa   83

Comparing Object Values and Classes   84

Comparing Objects   85

Determining the Class of an Object   87

Summary   87

Q&A   88

Quiz   88

Questions   89

Certification Practice   89

Exercises   90

4 Lists, Logic, and Loops   91

Arrays   92

Declaring Array Variables   92

Creating Array Objects   93

Accessing Array Elements   94

Changing Array Elements   95

Multidimensional Arrays    97

Block Statements   98

If Conditionals   99

Switch Conditionals   101

The Ternary Operator   107

For Loops   108

While and Do Loops   111

While Loops   111

Do-While Loops   113

Breaking Out of Loops   114

Labeled Loops   114

Summary   115

Q&A   115

Quiz   116

Questions   116

Certification Practice   117

Exercises   117

5 Creating Classes and Methods   119

Defining Classes  120

Creating Instance and Class Variables   120

Defining Instance Variables   120

Class Variables   121

Creating Methods   121

Defining Methods   122

The this Keyword   124

Variable Scope and Method Definitions   125

Passing Arguments to Methods   126

Class Methods   127

Creating Java Applications   129

Helper Classes   130

Java Applications and Command-Line Arguments   130

Passing Arguments to Java Applications   130

Handling Arguments in Your Java Application   131

Creating Methods with the Same Name   133

Constructors   136

Basic Constructors   137

Calling Another Constructor   138

Overloading Constructors   138

Overriding Methods   140

Creating Methods That Override Existing Methods   140

Calling the Original Method   142

Overriding Constructors   143

Summary   144

Q&A   145

Quiz   146

Questions   146

Certification Practice   146

Exercises   148

6 Packages, Interfaces, and Other Class Features   149

Modifiers   150

Access Control for Methods and Variables   151

Static Variables and Methods   157

Final Classes, Methods, and Variables   159

Variables   159

Methods   160

Classes   160

Abstract Classes and Methods   161

Packages   162

The import Declaration   163

Class Name Conflicts   165

Creating Your Own Packages   165

Picking a Package Name   165

Creating the Folder Structure   166

Adding a Class to a Package   166

Packages and Class Access Control   166

Interfaces   167

The Problem of Single Inheritance   167

Interfaces and Classes   168

Implementing and Using Interfaces   168

Implementing Multiple Interfaces   169

Other Uses of Interfaces   169

Creating and Extending Interfaces   170

New Interfaces   170

Methods Inside Interfaces   171

Extending Interfaces   172

Creating an Online Storefront   172

Inner Classes   179

Summary   181

Q&A   182

Quiz   183

Questions   183

Certification Practice   183

Exercises   185

7 Exceptions and Threads   187

Exceptions   188

Exception Classes  190

Managing Exceptions   191

Exception Consistency Checking   191

Protecting Code and Catching Exceptions   192

The finally Clause   195

Declaring Methods That Might Throw Exceptions   198

The throws Clause   199

Which Exceptions Should You Throw?    200

Passing on Exceptions   201

throws and Inheritance   202

Creating and Throwing Your Own Exceptions   203

Throwing Exceptions   203

Creating Your Own Exceptions   204

Combining throws, try, and throw   204

When and When Not to Use Exceptions   205

When to Use Exceptions   205

When Not to Use Exceptions   206

Bad Style Using Exceptions   206

Threads   207

Writing a Threaded Program   207

A Threaded Application   209

Stopping a Thread   214

Summary   215

Q&A   215

Quiz   217

Questions   217

Certification Practice   217

Exercises   218



WEEK 2: The Java Class Library   219

8 Data Structures   221



Moving Beyond Arrays   222

Java Structures   222

Iterator   224

Bit Sets   225

Array Lists   228

Looping Through Data Structures   231

Stacks   233

Map   235

Hash Maps   236

Generics   241

Summary   245

Q&A   245

Quiz   246

Questions   246

Certification Practice   246

Exercises   247

9 Working with Swing   249

Creating an Application   250

Creating an Interface   251

Developing a Framework   254

Creating a Component   255

Adding Components to a Container   256

Working with Components   258

Image Icons   259

Labels   261

Text Fields   262

Text Areas   263

Scrolling Panes   265

Check Boxes and Radio Buttons   266

Combo Boxes   269

Lists   271

Summary   273

Q&A   273

Quiz   274

Questions   274

Certification Practice   274

Exercises   275

10 Building a Swing Interface   277

Swing Features  278

Standard Dialog Boxes   278

Using Dialog Boxes   283

Sliders   286

Scroll Panes   288

Toolbars   289

Progress Bars   292

Menus   295

Tabbed Panes   299

Summary   301

Q&A   301

Quiz   302

Questions   302

Certification Practice  303

Exercises   304

11 Arranging Components on a User Interface   305

Basic Interface Layout   306

Laying Out an Interface   306

Flow Layout   307

Box Layout   309

Grid Layout   311

Border Layout   314

Mixing Layout Managers   316

Card Layout   317

Using Card Layout in an Application   319

Grid Bag Layout   325

Designing the Grid   327

Creating the Grid   329

Cell Padding and Insets   334

Summary   335

Q&A   335

Quiz   336

Questions   336

Certification Practice   337

Exercises   338

12 Responding to User Input   339

Event Listeners   340

Setting Up Components   341

Event-Handling Methods   342

Working with Methods   345

Action Events   345

Focus Events   346

Item Events   349

Key Events   351

Mouse Events   352

Mouse Motion Events   352

Window Events   357

Using Adapter Classes   357

Using Inner Classes   359

Summary   362

Q&A   362

Quiz   363

Questions   363

Certification Practice   363

Exercises   365

13 Creating Java2D Graphics   367

The Graphics2D Class   368

The Graphics Coordinate System   369

Drawing Text   370

Improving Fonts and Graphics with Antialiasing   372

Finding Information About a Font   372

Color   375

Using Color Objects   375

Testing and Setting the Current Colors   376

Drawing Lines and Polygons   377

User and Device Coordinate Spaces   377

Specifying the Rendering Attributes   378

Creating Objects to Draw   381

Drawing Objects   384

Summary   387

Q&A   387

Quiz   388

Questions   388

Certification Practice   388

Exercises   389

14 Developing Swing Applications   391

Java Web Start   392

Using Java Web Start   395

Creating a JNLP File   396

Supporting Web Start on a Server   405

Additional JNLP Elements   406

Improving Performance with SwingWorker   408

Summary   413

Q&A   414

Quiz   414

Questions   414

Certification Practice   415

Exercises   416



WEEK 3: Java Programming   417

15 Working with Input and Output   419



Introduction to Streams  420

Using a Stream   420

Filtering a Stream   421

Handling Exceptions   421

Byte Streams   422

File Streams   422

Filtering a Stream   426

Byte Filters   427

Character Streams   436

Reading Text Files   436

Writing Text Files   439

Files and Paths   440

Summary   443

Q&A   443

Quiz   444

Questions   444

Certification Practice   445

Exercises   446

16 Serializing and Examining Objects   447

Object Serialization   448

Object Output Streams   449

Object Input Streams  452

Transient Variables   455

Checking an Object’s Serialized Fields   456

Inspecting Classes and Methods with Reflection   457

Inspecting and Creating Classes   457

Working with Each Part of a Class   459

Inspecting a Class   461

Summary  463

Q&A   463

Quiz   464

Questions   464

Certification Practice   465

Exercises   465

17 Communicating Across the Internet   467

Networking in Java   468

Opening a Stream Over the Net   468

Sockets   473

Socket Servers   476

Testing the Server   479

The java.nio Package   481

Buffers   481

Channels   485

Summary   495

Q&A   496

Quiz   496

Questions   496

Certification Practice   497

Exercises   498

18 Accessing Databases with JDBC 4.1 and Derby   499

Java Database Connectivity   500

Database Drivers   501

Examining a Database   501

Reading Records from a Database   503

Writing Records to a Database   509

Moving Through Resultsets   516

Summary   517

Q&A   518

Quiz   518

Questions   518

Certification Practice   519

Exercises   519

19 Reading and Writing RSS Feeds   521

Using XML   522

Designing an XML Dialect   525

Processing XML with Java   526

Processing XML with XOM   526

Creating an XML Document   528

Modifying an XML Document   532

Formatting an XML Document   536

Evaluating XOM   538

Summary   540

Q&A   541

Quiz   542

Questions   542

Certification Practice.    542

Exercises   543

20 XML Web Services   545

Introduction to XML-RPC   546

Communicating with XML-RPC   547

Sending a Request   548

Responding to a Request   549

Choosing an XML-RPC Implementation   550

Using an XML-RPC Web Service   552

Creating an XML-RPC Web Service   555

Summary   560

Q&A   561

Quiz   561

Questions   561

Certification Practice   562

Exercises   563

21 Writing Android Apps for Java   565

The History of Android   566

Writing an Android App   567

Organizing an Android Project   569

Creating the Program   570

Using an Android Emulator   573

Creating a Debug Configuration   574

Running the App   575

Designing an Android App   577

Preparing Resources   578

Configuring a Manifest File   582

Designing the Graphical User Interface   582

Writing Code   585

Summary   591

Q&A   591

Quiz  592

Questions   592

Certification Practice   592

Exercises   592

Appendixes   593



A Using the NetBeans Integrated Development Environment   595

B This Book’s Website   603

C Setting Up an Android Development Environment   605

D Using the Java Development Kit   613

E Programming with the Java Development Kit   635

Quiz Answers   659