Java 23 for Absolute Beginners: Learn the Fundamentals of Java Programming. 3 Ed

Table of Contents....5

About the Author....13

About the Technical Reviewer....14

Acknowledgments....15

Chapter 1: An Introduction to Java and Its History....16

How It All Started....16

Who This Book Is For....17

How This Book Is Structured....19

Conventions....20

When Java Was Owned by Sun Microsystems....21

How Is Java Portable?....25

Sun Microsystem’s Java Versions....27

Oracle Takes Over....32

Java 7....32

Java 8....34

Java 9....36

Java 10....37

Java 11....39

Java 12....40

Java 13....41

Java 14....41

Java 15....42

Java 16....43

Java 17....44

Java 18....45

Java 19....45

Java 20....46

Java 21....46

Java 22....48

Java 23....49

Prerequisites....50

Summary....51

Chapter 2: Preparing Your Development Environment....52

Installing Java....53

The JAVA_HOME Environment Variable....58

JAVA_HOME on Windows....58

JAVA_HOME on macOS....63

JAVA_HOME on Linux....65

Running Java Code....66

Using JShell....66

Running Java Source Files Directly Using Java 21....72

Running Java Source Files Directly Using Java 22....75

Installing Apache Maven....82

Installing Git....83

Install a Java IDE....84

Summary....88

Chapter 3: Getting Your Feet Wet....89

Core Syntax Parts....89

Java Fundamental Building Blocks: Packages, Modules, and Classes....91

Packages....92

Access Modifiers....98

Modules....107

Advanced Module Configurations....111

How to Determine the Structure of a Java Project....115

The HelloWorld! Project in IntelliJ IDEA....116

The HelloWorld! Project Compiled and Executed from the Command Line....124

Putting the HelloWorld Class in a Package....126

Configuring the com.sandbox Module....129

Java Projects Using Build Tools, Mostly Maven....131

Explaining and Enriching the Hello World! Class....135

Summary....143

Chapter 4: Java Syntax....144

Base Rules of Writing Java Code....145

Package Declaration....146

Import Section....147

Java Grammar....151

Java Identifiers and Variables....155

Java Comments....156

Java Types....157

Classes....157

Fields....158

Class Variables....160

Encapsulating Data....162

Methods....166

Constructors....169

Abstraction and Inheritance....174

Enums....183

Interfaces....188

Default Methods in Interfaces....195

Static Methods and Constants in Interfaces....199

Private Methods in Interfaces....201

Records....203

Sealed Classes and Interfaces....208

Hidden Classes....211

Annotation Types....212

Lambda Expressions....212

Exceptions....214

Catch the exception, print an appropriate message, and exit the application....218

Throw an appropriate exception type....220

Perform a dummy initialization....223

try/catch Blocks....224

Generics....225

var and the Diamond Operator....228

Unnamed Patterns and Unnamed Variables....230

Summary....231

Java Keywords....232

Chapter 5: Data Types....237

Stack and Heap Memory....237

Introduction to Java Data Types....246

Primitive Data Types....246

Reference Data Types....249

Java Primitive Types....254

The boolean Type....255

The char Type....256

Numeric Primitive Types....258

Java Integer Primitive Types....260

Java Real Primitive Types....261

Java Reference Types....265

Arrays....271

The String Type....282

Useful String Methods Added After Java 8....290

Escaping Characters....292

Text Blocks....294

String Concatenation....299

Wrapper Classes for Primitive Types....301

Date/Time API....304

Collections....311

Concurrency-Specific Types....325

Classic Thread Creation (Before Java 21)....325

Java 21 Threads New Syntax and Virtual Threads....333

Asynchronous Programming Using CompletableFuture....340

Structured Concurrency....343

Summary....349

Chapter 6: Operators....350

The Assignment Operator....351

Explicit Type Conversion: (typem) and instanceof....354

Type Patterns....357

Record Patterns....360

Primitive Patterns....364

Numerical Operators....368

Unary Operators....368

Incrementors and Decrementors....368

Sign Operators....370

Negation Operator....371

Binary Operators....371

The + (Plus/Addition/Concatenation) Operator....371

The - (Minus) Operator....374

The * (Multiply) Operator....375

The / (Divide) Operator....376

The % (Modulus) Operator....377

Relational Operators....380

The == (Equals) Operator....380

The Other Comparison Operators....382

Bitwise Operators....385

Bitwise (~) NOT....386

Bitwise (&) AND....388

Bitwise Inclusive (|) OR....389

Bitwise Exclusive (^) OR....391

Logical Operators....392

Shift Operators....397

The << Shift Left Operator....397

The >> Shift Right Operator....398

The >>> Unsigned Shift Right Operator....401

The Elvis Operator....403

Summary....404

Chapter 7: Controlling the Flow....405

if-else Statement....407

switch....413

The Classic switch Statement....413

The switch Expression....418

switch with String Options....420

switch with enum Options....422

Pattern Matching for switch....427

Record Patterns for switch....432

Looping Statements....433

for Statement....435

while Statement....443

do-while Statement....449

Breaking Loops and Skipping Steps....456

break Statement....457

continue Statement....459

return Statement....461

Controlling the Flow Using try-catch Constructions....463

Summary....468

Chapter 8: The Stream API....469

Introduction to Streams....470

Creating Streams....473

Creating Streams from Collections....474

Creating Streams from Arrays....479

Creating Empty Streams....481

Creating Finite Streams....482

Streams of Primitives and Streams of Strings....489

Short Introduction to Optional....492

How to Use Streams Like a Pro....498

Terminal Functions forEach and forEachOrdered....500

Intermediate Operation filter and Terminal Operation toArray....502

Intermediate Operations map and flatMap and Terminal Operation collect....503

Intermediate Operation sorted and Terminal Operation findFirst....509

Intermediate Operation distinct and Terminal Operation count....510

Intermediate Operation limit and Terminal Operations min and max....511

Terminal Operations sum and reduce....512

Intermediate Operation peek....514

Intermediate Operation skip and Terminal Operations findAny, anyMatch, allMatch, and noneMatch....514

Intermediate Operation gather....518

Creating a Custom Gatherer....520

Built-In Gatherers....527

Debugging Stream Pipelines....530

Summary....535

Chapter 9: Debugging, Testing, and Documenting....537

Debugging....538

Logging....538

Logging with System.out.print....542

Logging with JUL....546

Logging with SLF4J and Logback....560

Debug Using Assertions....569

Step-By-Step Debugging....574

Inspect a Running Application Using Java Tools....578

jps....579

jcmd....580

jconsole....583

Using JDK Mission Control....587

Accessing the Java Process API....588

Testing....596

Test Code Location....598

Building an Application to Test....599

Introducing JUnit....600

Using Fakes....605

Using Stubs....612

Using Mocks....617

Documenting....624

Summary....638

Chapter 10: Making Your Application Interactive....640

Reading User Data from the Command Line....640

Using System.in....641

Using java.util.Scanner....642

Using java.io.Console....649

Building Applications Using Swing....652

Introducing JavaFX....665

Internationalization....677

Building a Web Application....688

Simple Application Server....692

The jwebserver Command-Line Tool....692

Using SimpleFileServer....695

Java Web Application with an Embedded Server....703

Java Web Application on a Standalone Server....711

Summary....721

Chapter 11: Working with Files....722

Java IO and NIO APIs....722

File Handlers....724

isFile....725

getAbsolutePath....726

getParent, getName, length, isHidden, canRead, and canWrite....727

Handling Directories: list() and listFiles()....728

createNewFile(), exists(), createTempFile(..), and deleteOnExit()....730

renameTo....732

Path Handlers....733

Reading Files....740

Using Scanner to Read Files....740

Using Files Utility Methods to Read Files....741

Using Readers to Read Files....743

Using InputStream to Read Files....748

Writing Files....751

Writing Files Using Files Utility Methods....751

Using Writer to Write Files....754

Using OutputStream to Write Files....759

Using Java NIO to Manage Files....762

Serialization and Deserialization....768

Byte Serialization....769

XML Serialization....772

JSON Serialization....778

The Media API....783

Using JavaFX Image Classes....797

Writing and Reading from Databases....800

Summary....806

Chapter 12: The Publish/Subscribe Framework....807

Reactive Programming and the Reactive Manifesto....808

Using the JDK Reactive Streams API....814

Reactive Streams Technology Compatibility Kit....828

Using Project Reactor....832

Summary....838

Chapter 13: Garbage Collection....840

Garbage Collection Basics....841

Oracle HotSpot JVM Architecture....841

How Many Garbage Collectors Are There?....846

Working with Garbage Collection from the Code....858

Using the finalize() Method....858

Heap Memory Statistics....865

Using Cleaner....871

Preventing GC from Deleting an Object....874

Using Weak References....878

Garbage Collection Exceptions and Causes....882

Summary....884

Appendix A: Java Modules....885

Modules....886

Advanced Module Configurations....890

Appendix B: IntelliJ IDEA Modules....907

Index....909

Write your first code in Java 23 using simple, step-by-step examples that model real-word objects and events, making learning easy. With this book you will be able to pick up core programming concepts without fuss and write efficient Java code in no time. Clear code descriptions and layout ensure you get your code running as soon as possible. Author Iuliana Cosmina focuses on practical knowledge and getting you up to speed quickly—all the bits and pieces a novice needs to get started programming in Java. 

In this edition, you will discover how Java has changed since version 17, and how to design and write code using the most recently introduced Java features such as new collection methods, virtual threads, pattern and record matching in switch expressions, structured concurrency tasks, unnamed classes and instance methods, and many more.

This book is a complete Java guide, covering the following topics: setting up a development environment, programming concepts and well-known programming principles, writing Java code following industry-specific design patterns and coding conventions, executing it, debugging, testing, documenting it and even using specialized tools such as IntelliJ IDEA for writing Java code, Maven for building, JUnit Jupiter for testing, and in-memory and Docker-hosted databases or data storage. After reading this book, you’ll have all the necessary skills and knowledge to pass an interview for a starting Java development position.

What You Will Learn

• Set up a Java development environment
• Use the Java language to write high-quality code
• Understand fundamental programming concepts and algorithms
• Use virtual threads, records, and other Java renown features
• Debug, test, and document Java code
• Improve performance by customizing the Garbage Collector

Who This Book Is For

Those who are new to programming and want to learn Java and use it to build efficient solutions