Java—from first steps to first apps Knowing Java is a must-have programming skill for any programmer. It’s used in a wide array of programming projects—from enterprise apps and mobile apps to big data, scientific, and financial uses. The language regularly ranks #1 in surveys of the most popular language based on number of developers, lines of code written, and real-world usage. It’s also the language of choice in AP Computer Science classes taught in the U.S.  This guide provides an easy-to-follow path from understanding the basics of writing Java code to applying those skills to real projects. Split into eight minibooks covering core aspects of Java, the book introduces the basics of the Java language and object-oriented programming before setting you on the path to building web apps and databases. • Get up to speed on Java basics • Explore object-oriented programming • Learn about strings, arrays, and collections • Find out about files and databases Step-by-step instructions are provided to ensure that you don't get lost at any point along the way.

Table of Contents:
Introduction 1 About This Book   2 Foolish Assumptions   2 Icons Used in This Book   3 Beyond the Book   4 Where to Go from Here   4 Book 1: Java Basics   5 Chapter 1: Welcome to Java   7 What Is Java, and Why Is It So Great?   8 Platform independence   8 Object orientation   9 The Java API 10 The Internet   10 Java versus Other Languages 11 Important Features of the Java Language   12 Type checking   13 Exception handling   14 On the Downside: Java’s Weaknesses 15 Java Version Insanity   16 What’s in a Name?   18 Chapter 2: Installing and Using Java Tools   19 Downloading and Installing the Java Development Kit   20 Downloading the JDK 20 Installing the JDK   21 Perusing the JDK folders   21 Setting the path   22 Using Java’s Command-Line Tools 24 Compiling a program 24 Compiling more than one file 25 Using Java compiler options   26 Running a Java program   28 Using the javap command   28 Using Java Documentation   30 Chapter 3: Working with Text Pad   33 Downloading and Installing TextPad 33 Editing Source Files   35 Compiling a Program 37 Running a Java Program   38 Book 2: Programming Basics   41 Chapter 1: Java Programming Basics   43 Looking at the Infamous Hello, World! Program 44 Dealing with Keywords   47 Working with Statements   49 Types of statements   49 White space 50 Working with Blocks   52 Creating Identifiers   53 Crafting Comments   54 End-of-line comments   54 Traditional comments   54 JavaDoc comments   55 Introducing Object-Oriented Programming 56 Understanding classes and objects 56 Understanding static methods 56 Creating an object from a class   57 Viewing a program that uses an object   58 So what’s the difference?   60 Importing Java API Classes   61 Chapter 2: Working with Variables and Data Types   63 Declaring Variables   64 Declaring two or more variables in one statement   65 Declaring class variables 65 Declaring instance variables 66 Declaring local variables   67 Initializing Variables 68 Initializing variables with assignment statements   69 Initializing variables with initializers   70 Using Final Variables (Constants)   70 Working with Primitive Data Types   71 Integer types 72 Floating-point types 74 The char type   76 The Boolean type   77 Using wrapper classes 78 Using reference types   78 Using inferred variable types   80 Working with Strings   81 Declaring and initializing strings   82 Combining strings   82 Converting primitives to strings 83 Converting strings to primitives 84 Converting and Casting Numeric Data   85 Automatic conversions   85 Type casting   86 Thinking Inside the Box 87 Understanding Scope   87 Shadowing Variables   89 Printing Data with System out   90 Using standard input and output streams 91 Using System out and System  err   92 Getting Input with the Scanner Class   93 Importing the Scanner class 94 Declaring and creating a Scanner object   94 Getting input 94 Getting Input with the JOptionPane Class   96 Using enum to Create Your Own Data Types   98 Chapter 3: Working with Numbers and Expressions 99 Working with Arithmetic Operators   99 Dividing Integers   102 Combining Operators   104 Using the Unary Plus and Minus Operators   105 Using Increment and Decrement Operators   106 Using the Assignment Operator   108 Using Compound Assignment Operators   110 Using the Math Class 111 Using constants of the Math class 112 Working with mathematical functions   113 Creating random numbers 116 Rounding functions   119 Formatting Numbers 121 Recognizing Weird Things about Java Math 123 Integer overflow   123 Floating-point weirdness 124 Division by zero   125 Chapter 4: Making Choices 129 Using Simple Boolean Expressions   130 Using if Statements   132 Simple if statements   132 if-else statements 135 Nested if statements   136 else-if statements 140 Using Mr Spock’s Favorite Operators (Logical Ones, of Course)   142 Using the ! operator 142 Using the & and && operators 144 Using the | and || operators 145 Using the ^ operator   146 Combining logical operators   147 Using the Conditional Operator 148 Comparing Strings   149 Chapter 5: Going Around in Circles (Or, Using Loops)   151 Using Your Basic while Loop   152 The while statement   152 A counting loop   152 Breaking Out of a Loop   154 Looping Forever   154 Letting the user decide when to quit   156 Letting the user decide in another way   157 Using the continue Statement   158 Running do-while Loops   159 Validating Input from the User   161 Using the Famous for Loop   164 Understanding the formal format of the for loop 164 Scoping out the counter variable 166 Counting even numbers   167 Counting backward   168 Using for loops without bodies   169 Ganging up your expressions 170 Omitting expressions   172 Breaking and continuing your for loops 172 Nesting Your Loops   173 A simple nested for loop 174 A guessing game   174 Chapter 6: Pulling a Switcheroo 179 Battling else-if Monstrosities   179 Viewing an example else-if program 180 Creating a better version of the example program   181 Using the switch Statement   183 Viewing a boring switch example, complete with flowchart   184 Putting if statements inside switch statements 186 Creating Character Cases   187 Intentionally Leaving Out a Break Statement   188 Switching with Strings   192 Enhanced Switch Features with Java 13   193 Chapter 7: Adding Some Methods to Your Madness   197 The Joy of Methods   198 The Basics of Making Methods   198 An example   200 Another example   201 Methods That Return Values   203 Declaring the method’s return type   203 Using the return statement to return the value   204 Using a method that returns a type   205 You gotta have a proper return statement   205 Trying another version of the guessing-game program 207 Methods That Take Parameters 210 Declaring parameters   211 Scoping out parameters   212 Understanding pass-by-value   213 Trying yet another version of the guessing-game program   214 Chapter 8: Handling Exceptions 217 Understanding Exceptions   218 Witnessing an exception   219 Finding the culprit   220 Catching Exceptions 221 A simple example 222 Another example   222 Handling Exceptions with a Preemptive Strike   224 Catching All Exceptions at Once 226 Displaying the Exception Message   227 Using a finally Block 228 Handling Checked Exceptions   231 Viewing the catch-or-throw compiler error   232 Catching FileNotFoundException 232 Throwing the FileNotFoundException 233 Throwing an exception from main   234 Swallowing exceptions   234 Throwing Your Own Exceptions 236 Book 3: Object-oriented Programming   239 Chapter 1: Understanding Object-Oriented Programming   241 What Is Object-Oriented Programming?   242 Understanding Objects   243 Objects have identity 243 Objects have type 244 Objects have state   245 Objects have behavior 246 Understanding the Life Cycle of an Object 247 Working with Related Classes   248 Inheritance   248 Interfaces 249 Designing a Program with Objects   250 Diagramming Classes with UML   251 Drawing classes   252 Drawing arrows   253 Chapter 2: Making Your Own Classes   255 Declaring a Class   256 Picking class names   256 Knowing what goes in the class body   257 Seeing where classes go   258 Working with Members 259 Understanding fields   259 Understanding instance methods   260 Understanding visibility 261 Using Getters and Setters 261 Overloading Methods   264 Creating Constructors   266 Creating basic constructors   266 Creating default constructors   267 Calling other constructors   268 Finding More Uses for the this Keyword   270 Using Initializers   271 Using Records 273 Chapter 3: Working with Statics   275 Understanding Static Fields and Methods   275 Working with Static Fields 276 Using Static Methods 277 Counting Instances   278 Preventing Instances   281 Using Static Initializers   282 Chapter 4: Using Subclasses and Inheritance   285 Introducing Inheritance   285 Motorcycles, trains, and automobiles 287 Game play   287 A businesslike example 288 Inheritance hierarchies   288 Creating Subclasses 289 Overriding Methods 291 Protecting Your Members 292 Using this and super in Your Subclasses   293 Understanding Inheritance and Constructors 294 Using final   295 Final methods 296 Final classes   296 Casting Up and Down   297 Determining an Object’s Type   299 Poly What? 300 Creating Custom Exceptions   302 Tracing the Throwable hierarchy 302 Creating an exception class   304 Throwing a custom exception   305 Chapter 5: Using Abstract Classes and Interfaces   307 Using Abstract Classes   307 Using Interfaces   310 Creating a basic interface   311 Implementing an interface   312 Using an interface as a type   313 More Things You Can Do with Interfaces   314 Adding fields to an interface   314 Extending interfaces   315 Using interfaces for callbacks 316 Using Additional Interface Method Types   320 Chapter 6: Using the Object and Class Classes   323 The Mother of All Classes: Object   323 Every object is an Object 324 Object as a type   324 Methods of the Object class 325 Primitives aren’t objects   326 The toString Method   327 Using toString   327 Overriding toString   328 The equals Method   330 Using equals   331 Overriding the equals method 332 The clone Method   336 Implementing the clone method   336 Using clone to create a shallow copy   339 Creating deep copies 341 The Class Class   346 Chapter 7: Using Inner Classes, Anonymous Classes, and Lambda Expressions   349 Declaring Inner Classes 350 Understanding inner classes   350 Viewing an example 351 Using Static Inner Classes 354 Using Anonymous Inner Classes   355 Creating an anonymous class   356 Creating a program with an anonymous class   357 Using Lambda Expressions 359 Chapter 8: Working with Packages and the Java Module System   361 Working with Packages   362 Importing classes and packages   362 Creating your own packages   363 An example   365 Putting Your Classes in a JAR File 366 jar command-line options 366 Archiving a package   367 Adding a jar to your classpath   368 Running a program directly from an archive 369 Using Javadoc to Document Your Classes   370 Adding Javadoc comments   371 Using the javadoc command   373 Viewing Javadoc pages   374 Using the Java Module System 375 Understanding modules   376 The module-info  java file   377 Setting up folders for a module 378 Compiling a module 379 Creating a modular JAR file 379 Running a modular JAR file   380 Book 4: Strings, Arrays, and Collections   381 Chapter 1: Working with Strings   383 Reviewing Strings 384 Using the String Class   386 Finding the length of a string   388 Making simple string modifications   389 Extracting characters from a string   389 Extracting substrings from a string   390 Splitting a string   392 Replacing parts of a string   394 Using the StringBuilder and StringBuffer Classes 395 Creating a StringBuilder object   396 Using StringBuilder methods   396 Viewing a StringBuilder example 398 Using the CharSequence Interface   399 Chapter 2: Using Arrays   401 Understanding Arrays   401 Creating Arrays 402 Initializing an Array   404 Using for Loops with Arrays   404 Solving Homework Problems with Arrays   405 Using the Enhanced for Loop 408 Using Arrays with Methods   409 Using Varargs   410 Using Two-Dimensional Arrays   411 Creating a two-dimensional array   412 Accessing two-dimensional array elements 413 Initializing a two-dimensional array   414 Using jagged arrays   415 Going beyond two dimensions   416 Working with a Fun but Complicated Example: A Chessboard   417 Using the Arrays Class 425 Filling an array   426 Copying an array   427 Sorting an array   428 Searching an array 429 Comparing arrays   429 Converting arrays to strings   430 Chapter 3: Using the ArrayList Class   431 Understanding the ArrayList Class   432 Creating an ArrayList Object   435 Adding Elements   436 Accessing Elements   437 Printing an ArrayList   438 Using an Iterator   438 Updating Elements   440 Deleting Elements   442 Chapter 4: Using the LinkedList Class   445 Understanding the LinkedList Class   446 Creating a LinkedList   450 Adding Items to a LinkedList   450 Retrieving Items from a LinkedList   452 Updating LinkedList Items   454 Removing LinkedList Items 455 Chapter 5: Creating Generic Collection Classes   457 Why Generics?   458 Creating a Generic Class   459 A Generic Stack Class   461 Using Wildcard-Type Parameters   464 A Generic Queue Class   466 Chapter 6: Using Bulk Data Operations with Collections   471 Looking At a Basic Bulk Data Operation 473 Looking Closer at the Stream Interface   475 Using Parallel Streams   478 Book 5: Programming Techniques 481 Chapter 1: Programming Threads   483 Understanding Threads   484 Creating a Thread   485 Understanding the Thread class   485 Extending the Thread class 486 Creating and starting a thread 488 Implementing the Runnable Interface   488 Using the Runnable interface 489 Creating a class that implements Runnable   489 Using the CountDownApp class 491 Creating Threads That Work Together   493 Using an Executor   497 Synchronizing Methods 499 Creating a Lock 503 Coping with Threadus Interruptus   505 Finding out whether you’ve been interrupted 505 Aborting the countdown 506 Chapter 2: Using Regular Expressions   511 Creating a Program for Experimenting with Regular Expressions   512 Performing Basic Character Matching   515 Matching single characters 515 Using predefined character classes   515 Using custom character classes 518 Using ranges   519 Using negation   520 Matching multiple characters 520 Using escapes 521 Using parentheses to group characters   522 Using the pipe symbol 523 Using Regular Expressions in Java Programs 524 Understanding the String problem   524 Using regular expressions with the String class   525 Using the Pattern and Matcher classes   526 Chapter 3: Using Recursion   529 Calculating the Classic Factorial Example 529 The nonrecursive solution   530 The recursive solution 530 Displaying Directories   532 Writing Your Own Sorting Routine   536 Understanding how Quicksort works   536 Using the sort method   537 Using the partition method   538 Putting it all together 540 Chapter 4: Working with Dates and Times 545 Pondering How Time is Represented   546 Picking the Right Date and Time Class for Your Application   547 Using the now Method to Create a Date-Time Object   548 Using the parse Method to Create a Date-Time Object   550 Using the of Method to Create a Date-Time Object   551 Using the Month enumeration 552 Using the ZoneId class 553 Using the ZoneOffset class   554 Looking Closer at the LocalDate Class   554 Extracting Information About a Date   556 Comparing Dates   557 Calculating with Dates 558 Formatting Dates   560 Looking at a Fun Birthday Calculator   562 Chapter 5: IoT Programming with Raspberry Pi   567 Introducing the Raspberry Pi   568 Setting Up a Raspberry Pi   570 Installing Java on a Raspberry Pi   571 Installing the Pi4J Library   572 Configuring the Geany Integrated Development Environment for Java Development   572 Examining GPIO Ports   574 Connecting an LED to a GPIO Port   576 Building a Raspberry Pi LED Circuit 581 Parts 581 Steps   582 Examining the Pi4J Library   582 Importing GPIO Types   583 Instantiating a GpioController   584 Provisioning GPIO Pins   584 Controlling the Pin State   587 The Morse Code Program 589 The Cylon Eyes Program   593 Assembling the Cylon Eyes circuit   593 Running the Cylon Eyes program   596 Working with Input Pins   598 Understanding active-high and active-low inputs 599 Provisioning a digital input   600 Reading the state of a digital input pin 601 Building a circuit with a digital input pin   602 Running the Button Switcher Program 604 Finding a Better Way to Handle Input Events   606 Crafting a state change event listener   607 Adding an event handler to a pin   608 Using automatic debounce 609 Working with the EventSwitcher program   610 Book 6: Javafx 613 Chapter 1: Hello, JavaFX!   615 Perusing the Possibilities of JavaFX   616 Getting Ready to Run JavaFX   618 Looking at a Simple JavaFX Program 620 Importing JavaFX Packages 622 Extending the Application Class 623 Launching the Application   624 Overriding the start Method   625 Creating a Button 626 Handling an Action Event   627 Creating a Layout Pane   629 Making a Scene   630 Setting the Stage   631 Examining the Click Counter Program   632 Chapter 2: Handling Events   637 Examining Events 638 Handling Events   639 Implementing the EventHandler Interface   641 Handling Events with Inner Classes   644 Handling Events with Anonymous Inner Classes   647 Using Lambda Expressions to Handle Events   649 Chapter 3: Setting the Stage and Scene Layout   655 Examining the Stage Class   656 Examining the Scene Class   659 Switching Scenes   661 Creating an Alert Box 666 Exit, Stage Right   670 Creating a Close button 671 Handling the CloseRequest event   672 Putting it all together 674 Chapter 4: Using Layout Panes to Arrange Your Scenes 677 Working with Layout Panes   678 Introducing five JavaFX layout panes   678 Creating layout panes   679 Combining layout panes   680 Using the HBox Layout   680 Spacing Things Out   682 Adding Space with Margins   684 Adding Space by Growing Nodes   685 Using the VBox Layout   687 Aligning Nodes in a Layout Pane   689 Using the Flow Layout   690 Using the Border Layout 694 Using the GridPane Layout 697 Sketching out a plan   697 Creating a grid pane   698 Working with grid pane constraints   701 Examining a grid pane example 703 Chapter 5: Getting Input from the User   709 Using Text Fields   710 Validating Numeric Data 717 Using Check Boxes 719 Using Radio Buttons   721 Chapter 6: Choosing from a List   725 Using Choice Boxes   725 Creating a choice box   727 Setting a default value 728 Getting the selected item   729 Working with Observable Lists 729 Listening for Selection Changes 732 Using Combo Boxes 734 Creating combo boxes   735 Getting the selected item   736 Handling combo box events 737 Using List Views   738 Creating a list view   739 Getting the selected items   740 Using Tree Views   740 Building a tree   742 Creating a TreeView control   745 Getting the selected node 746 Looking at a complete program that uses a tree view   748 Book 7: Web Programming 751 Chapter 1: Creating Servlets   753 Understanding Servlets 753 Using Tomcat   755 Installing Tomcat   755 Testing Tomcat   756 Creating a Simple Servlet   757 Creating the folder structure for a servlet   758 Creating the web  xml file   758 Importing the servlet packages   760 Extending the HttpServlet class   760 Printing to a web page   761 Responding with HTML   762 Running a Servlet   764 Improving the HelloWorld Servlet   765 Getting Input from the User 767 Working with forms   767 Using the InputServlet servlet   768 Using Classes in a Servlet   769 Chapter 2: Using JavaServer Pages   775 Understanding JavaServer Pages 776 Using UEL Expressions   778 Unified Expression Language 778 JSP Standard Tag Library 780 Looking at Core Tags   782 Using c:out   783 Working with variables   783 Getting conditional   784 Creating loops   785 Formatting Numbers 786 Considering the Controller Servlet   788 Setting request attributes 788 Redirecting to the JSP page 789 The ListMovies Application Meets JSP 790 Chapter 3: Using JavaBeans 797 Getting to Know JavaBeans 797 Looking Over a Sample Bean   799 Using Beans with JSP Pages   801 Creating bean instances   802 Getting property values   803 Setting property values   803 Viewing a JSP page that uses a bean   804 Scoping Your Beans 806 A shopping cart application   807 The shopping cart page 808 The BookCart JavaBean 810 Chapter 4: Using HttpClient   815 Understanding HTTP   815 Diving into HTTP 817 Looking at a simple HTTP exchange   822 Getting Started with Java’s HTTP Client Library   822 HttpClient   823 HttpRequest   824 HttpResponse   827 Using the send method 828 Putting It All Together   829 The HTTP Tester Program 831 Index   835