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