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Java All-in-One For Dummies, 4th Edition

Name: Java All-in-One For Dummies, 4th Edition
Author: Doug Lowe
ISBN: 9781118408032

by Doug Lowe

March 2014

Beginner

960 pages

19h 42m

English

For Dummies

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Introduction
About this BookFoolish AssumptionsIcons Used in This BookBeyond the BookWhere to Go from Here
Book I: Getting Started with Java Basics
Chapter 1: Welcome to Java
What Is Java, and Why Is It So Great?Platform independenceObject orientationThe Java APIThe InternetJava versus Other LanguagesImportant Features of the Java LanguageType checkingAutomatic memory managementException handlingOn the Downside: Java's WeaknessesJava Version InsanityWhat's in a Name?
Chapter 2: Installing and Using Java Tools
Downloading and Installing the Java Development KitDownloading the JDKInstalling the JDKPerusing the JDK foldersSetting the pathUsing Java's Command-Line ToolsCompiling a programCompiling more than one fileUsing Java compiler optionsRunning a Java programUsing the javap commandUsing Java DocumentationJava SE API DocsJava Language Specification
Chapter 3: Working with TextPad
Downloading and Installing TextPadEditing Source FilesCompiling a ProgramRunning a Java ProgramRunning an Applet
Book II: Programming Basics
Chapter 1: Java Programming Basics
Looking at the Infamous Hello, World! ProgramDealing with KeywordsWorking with StatementsTypes of statementsWhite spaceWorking with BlocksCreating IdentifiersCrafting CommentsEnd-of-line commentsTraditional commentsJavaDoc commentsIntroducing Object-Oriented ProgrammingUnderstanding classes and objectsUnderstanding static methodsCreating an object from a classViewing a program that uses an objectSo what's the difference?Importing Java API Classes
Chapter 2: Working with Variables and Data Types
Declaring VariablesDeclaring two or more variables in one statementDeclaring class variablesDeclaring instance variablesDeclaring local variablesInitializing VariablesInitializing variables with assignment statementsInitializing variables with initializersUsing Final Variables (Constants)Working with Primitive Data TypesInteger typesFloating-point typesThe char typeThe Boolean typeWrapper classesUsing Reference TypesWorking with StringsDeclaring and initializing stringsCombining stringsConverting primitives to stringsConverting strings to primitivesConverting and Casting Numeric DataAutomatic conversionsType castingThinking Inside the BoxUnderstanding ScopeShadowing VariablesPrinting Data with System.outUsing standard input and output streamsUsing System.out and System.errGetting Input with the Scanner ClassImporting the Scanner classDeclaring and creating a Scanner objectGetting inputGetting Input with the JOptionPane ClassUsing enum to Create Your Own Data Types
Chapter 3: Working with Numbers and Expressions
Working with Arithmetic OperatorsDividing IntegersCombining OperatorsUsing the Unary Plus and Minus OperatorsUsing Increment and Decrement OperatorsUsing the Assignment OperatorUsing Compound Assignment OperatorsUsing the Math ClassUsing constants of the Math classWorking with mathematical functionsCreating random numbersRounding functionsFormatting NumbersRecognizing Weird Things about Java MathInteger overflowFloating-point weirdnessDivision by zero
Chapter 4: Making Choices
Using Simple Boolean ExpressionsUsing if StatementsSimple if statementsif-else statementsNested if statementselse-if statementsUsing Mr. Spock's Favorite Operators (Logical Ones, of Course)Using the ! operatorUsing the & and && operatorsUsing the | and || operatorsUsing the ^ operatorCombining logical operatorsUsing the Conditional OperatorComparing Strings

Chapter 5: Going Around in Circles (Or, Using Loops)
Using Your Basic while LoopThe while statementA counting loopBreaking Out of a LoopLooping ForeverLetting the user decide when to quitLetting the user decide in another wayUsing the continue StatementRunning do-while LoopsValidating Input from the UserUsing the Famous for LoopUnderstanding the formal format of the for loopScoping out the counter variableCounting even numbersCounting backwardUsing for loops without bodiesGanging up your expressionsOmitting expressionsBreaking and continuing your for loopsNesting Your LoopsA simple nested for loopA guessing game
Chapter 6: Pulling a Switcheroo
Battling else-if MonstrositiesViewing an example else-if programCreating a better version of the example programUsing the switch StatementViewing a boring switch example, complete with flowchartPutting if statements inside switch statementsCreating Character CasesIntentionally Leaving Out a Break StatementSwitching with Strings
Chapter 7: Adding Some Methods to Your Madness
The Joy of MethodsThe Basics of Making MethodsAn exampleAnother exampleMethods That Return ValuesDeclaring the method's return typeUsing the return statement to return the valueUsing a method that returns a typeYou gotta have a proper return statementTrying another version of theguessing-game programMethods That Take ParametersDeclaring parametersScoping out parametersUnderstanding pass-by-valueTrying yet another version ofthe guessing-game program
Chapter 8: Handling Exceptions
Understanding ExceptionsWitnessing an exceptionFinding the culpritCatching ExceptionsA simple exampleAnother exampleHandling Exceptions with a Preemptive StrikeCatching All Exceptions at OnceDisplaying the Exception MessageUsing a finally BlockHandling Checked ExceptionsViewing the catch-or-throw compiler errorCatching FileNotFoundExceptionThrowing the FileNotFoundExceptionThrowing an exception from mainSwallowing exceptionsThrowing Your Own ExceptionsCatching Multiple Exceptions
Book III: Object-Oriented Programming
Chapter 1: Understanding Object-Oriented Programming
What Is Object-Oriented Programming?Understanding ObjectsObjects have identityObjects have typeObjects have stateObjects have behaviorUnderstanding the Life Cycle of an ObjectWorking with Related ClassesInheritanceInterfacesDesigning a Program with ObjectsDiagramming Classes with UMLDrawing classesDrawing arrows
Chapter 2: Making Your Own Classes
Declaring a ClassPicking class namesKnowing what goes in the class bodySeeing where classes goWorking with MembersUnderstanding fieldsUnderstanding methodsUnderstanding visibilityUsing Getters and SettersOverloading MethodsCreating ConstructorsCreating basic constructorsCreating default constructorsCalling other constructorsFinding More Uses for the this KeywordUsing Initializers
Chapter 3: Working with Statics
Understanding Static Fields and MethodsWorking with Static FieldsUsing Static MethodsCounting InstancesPreventing InstancesUsing Static Initializers
Chapter 4: Using Subclasses and Inheritance
Introducing InheritanceMotorcycles, trains, and automobilesGame playA businesslike exampleInheritance hierarchiesCreating SubclassesOverriding MethodsProtecting Your MembersUsing this and super in Your SubclassesUnderstanding Inheritance and ConstructorsUsing finalFinal methodsFinal classesCasting Up and DownDetermining an Object's TypePoly What?Creating Custom ExceptionsTracing the Throwable hierarchyCreating an exception classThrowing a custom exception
Chapter 5: Using Abstract Classes and Interfaces
Using Abstract ClassesUsing InterfacesCreating a basic interfaceImplementing an interfaceUsing an interface as a typeMore Things You Can Do with InterfacesAdding fields to an interfaceExtending interfacesUsing interfaces for callbacksUsing Default Methods
Chapter 6: Using the Object and Class Classes
The Mother of All Classes: ObjectEvery object is an ObjectObject as a typeMethods of the Object classPrimitives aren't objectsThe toString MethodUsing toStringOverriding toStringThe equals MethodUsing equalsOverriding the equals methodThe clone MethodImplementing the clone methodUsing clone to create a shallow copyCreating deep copiesThe Class Class
Chapter 7: Using Inner Classes, Anonymous Classes, and Lambda Expressions
Declaring Inner ClassesUnderstanding inner classesViewing an exampleUsing Static Inner ClassesWorking with Packages
Chapter 8: Packaging and Documenting Your Classes
Importing classes and packagesCreating your own packagesAn examplePutting Your Classes in a JAR Filejar command-line optionsArchiving a packageAdding a jar to your classpathRunning a program directly from an archiveUsing JavaDoc to Document Your ClassesAdding JavaDoc commentsUsing the javadoc commandViewing JavaDoc pages
Book IV: Strings, Arrays, and Collections
Chapter 1: Working with Strings
Reviewing StringsUsing the String ClassFinding the length of a stringMaking simple string modificationsExtracting characters from a stringExtracting substrings from a stringSplitting a stringReplacing parts of a stringUsing the StringBuilder and StringBuffer ClassesCreating a StringBuilder objectUsing StringBuilder methodsViewing a StringBuilder exampleUsing the CharSequence Interface
Chapter 2: Using Arrays
Understanding ArraysCreating ArraysInitializing an ArrayUsing for Loops with ArraysSolving Homework Problems with ArraysUsing the Enhanced for LoopUsing Arrays with MethodsUsing Two-Dimensional ArraysCreating a two-dimensional arrayAccessing two-dimensional array elementsInitializing a two-dimensional arrayUsing jagged arraysGoing beyond two dimensionsWorking with a Fun but Complicated Example: A ChessboardUsing the Arrays ClassFilling an arrayCopying an arraySorting an arraySearching an arrayComparing arraysConverting arrays to strings
Chapter 3: Using the ArrayList Class
Understanding the ArrayList ClassCreating an ArrayList ObjectAdding ElementsAccessing ElementsPrinting an ArrayListUsing an IteratorUpdating ElementsDeleting Elements
Chapter 4: Using the LinkedList Class
Understanding the LinkedList ClassCreating a LinkedListAdding Items to a LinkedListRetrieving Items from a LinkedListUpdating LinkedList ItemsRemoving LinkedList Items
Chapter 5: Creating Generic Collection Classes
Why Generics?Creating a Generic ClassA Generic Stack ClassUsing Wildcard-Type ParametersA Generic Queue ClassUsing the Diamond Operator
Chapter 6: Using Bulk Data Operations with Collections
Looking At a Basic Bulk Data OperationLooking Closer at the Stream InterfaceUsing Parallel Streams
Book V: Programming Techniques
Chapter 1: Programming Threads
Understanding ThreadsCreating a ThreadUnderstanding the Thread classExtending the Thread classCreating and starting a threadImplementing the Runnable InterfaceUsing the Runnable interfaceCreating a class that implements RunnableUsing the CountDownApp classCreating Threads That Work TogetherUsing an ExecutorSynchronizing MethodsCreating a LockCoping with Threadus InterruptusFinding out whether you've been interruptedAborting the countdown
Chapter 2: Network Programming
Understanding Network ProgrammingIP addresses and portsHost names, DNS, and URLstelnetGetting Information about Internet HostsThe InetAddress classA program that looks up host namesCreating Network Server ApplicationsThe Socket classThe ServerSocket classIntroducing BARTThe BartQuote classThe BartServer programThe BartClient programWorking with BartServer 2.0
Chapter 3: Using Regular Expressions
Creating a Program for Experimentingwith Regular ExpressionsPerforming Basic Character MatchingMatching single charactersUsing predefined character classesUsing custom character classesUsing rangesUsing negationMatching multiple charactersUsing escapesUsing parentheses to group charactersUsing the pipe symbolUsing Regular Expressions in Java ProgramsUnderstanding the String problemUsing regular expressions with the String classUsing the Pattern and Matcher classes
Chapter 4: Using Recursion
Calculating the Classic Factorial ExampleThe nonrecursive solutionThe recursive solutionDisplaying DirectoriesWriting Your Own Sorting RoutineUnderstanding how Quicksort worksUsing the sort methodUsing the partition methodPutting it all together
Chapter 5: Working with Dates and Times
Pondering How Time is RepresentedPicking the Right Date and Time Class for Your ApplicationUsing the now Method to Create a Date-Time ObjectUsing the parse Method to Create a Date-Time ObjectUsing the of Method to Create a Date-Time ObjectUsing the Month enumerationUsing the ZoneId classUsing the ZoneOffset classLooking Closer at the LocalDate ClassExtracting Information About a DateComparing DatesCalculating with DatesFormatting DatesLooking at a Fun Birthday Calculator
Chapter 6: Using BigDecimals
Seeing Why Java Can't AddDouble troubleAnother exampleBigDecimal to the Rescue!Creating BigDecimal ObjectsDoing BigDecimal ArithmeticRounding BigDecimal ValuesThe fundamentals of scaleThe how-to of roundingComparing BigDecimal ValuesConverting BigDecimals to StringsRevisiting Sales Tax
Book VI: Swing
Chapter 1: Swinging into Swing
Understanding Some Important Swing ConceptsSeeing what Swing doesViewing the Swing class hierarchyI've Been Framed!Saying Hello, World! in SwingPositioning the frame onscreenUsing the JPanel ClassUsing LabelsCreating ButtonsControlling the Layout of Components
Chapter 2: Handling Events
Examining EventsHandling EventsCreating a ClickMe ProgramUsing Inner Classes to Listen for EventsUsing Lambda Expressions to Handle EventsAdding an Exit ButtonCatching the WindowClosing EventRevisiting the ClickMe Program
Chapter 3: Getting Input from the User
Using Text FieldsLooking at a sample programUsing text fields for numeric entryCreating a validation classUsing Text AreasThe JTextArea classThe JScrollPane classUsing Check BoxesUsing Radio ButtonsUsing BordersUsing SlidersDesigning a Pizza-Ordering Program
Chapter 4: Choosing from a List
Using Combo BoxesCreating combo boxesGetting items from a combo boxHandling combo box eventsUsing ListsCreating a listGetting items from a listChanging list itemsUsing SpinnersUsing TreesBuilding a treeCreating a JTree componentGetting the selected nodeLooking at a complete program that uses a tree
Chapter 5: Using Layout Managers
Working with Layout ManagersIntroducing six Swing layout managersApplying layout managersUsing Flow LayoutUsing Border LayoutUsing Box LayoutUsing Grid LayoutUsing GridBag LayoutSketching out a planAdding components to a GridBag layoutWorking with GridBagConstraint constructorsViewing a GridBag layout exampleUsing Group Layout
Book VII: Web Programming
Chapter 1: Creating Applets
Understanding AppletsWorking with the JApplet ClassLooking at a Sample AppletCreating an HTML Page for an AppletTesting an Applet
Chapter 2: Creating Servlets
Understanding ServletsUsing TomcatInstalling and configuring TomcatStarting and stopping TomcatTesting TomcatCreating a Simple ServletImporting the servlet packagesExtending the HttpServlet classPrinting to a web pageResponding with HTMLRunning a ServletImproving the HelloWorld ServletGetting Input from the UserWorking with formsUsing the InputServlet servletUsing Classes in a Servlet
Chapter 3: Using JavaServer Pages
Understanding JavaServer PagesUsing Page DirectivesUsing ExpressionsUsing ScriptletsUsing DeclarationsUsing Classes
Book VIII: Files and Databases
Chapter 1: Working with Files
Using the File ClassKnowing the class constructors and methodsCreating a File objectCreating a fileGetting information about a fileGetting the contents of a directoryRenaming filesDeleting a fileUsing Command-Line ParametersChoosing Files in a Swing ApplicationCreating an Open dialog boxGetting the selected fileUsing file filtersUsing Path ObjectsCreating files with the Paths classGetting the contents of a directoryUsing a File Visitor to Walk a File Tree
Chapter 2: Working with File Streams
Understanding StreamsReading Character StreamsCreating a BufferedReaderReading from a character streamReading the movies.txt fileWriting Character StreamsConnecting a PrintWriter to a text fileWriting to a character streamWriting the movies.txt fileReading Binary StreamsCreating a DataInputStreamReading from a data input streamReading the movies.dat fileWriting Binary StreamsCreating a DataOutputStreamWriting to a binary streamWriting the movies.dat file
Chapter 3: Database for $100, Please
Defining a Relational DatabaseUnderstanding (and Pronouncing) SQLIntroducing SQL StatementsCreating a SQL DatabaseQuerying a DatabaseUsing a basic select statementNarrowing the queryExcluding rowsUsing singleton selectsFinding what something sounds likeUsing column functionsSelecting data from more than one tableEliminating duplicatesUpdating and Deleting RowsUsing the delete statementUsing the update statement
Chapter 4: Using JDBC to Connect to a Database
Setting Up a DriverConnecting to a DatabaseQuerying a DatabaseExecuting a select statementNavigating through the result setGetting data from a result setPutting it all together: A program that reads from a databaseUpdating SQL DataUsing an Updatable RowSet ObjectDeleting a rowUpdating the value of a row columnInserting a row
Chapter 5: Working with XML
Defining XMLTagsAttributesThe XML declarationThe movies.xml fileUsing a DTDProcessing XML in Two Ways: DOM and SAXReading a DOM DocumentCreating a DocumentBuilderFactoryConfiguring the DocumentBuilderFactoryCreating a document builder and the documentUsing the getDocument methodReading DOM NodesProcessing elementsGetting attribute valuesGetting child element valuesPutting It All Together: A Program That Lists Movies
Book IX: Fun and Games
Chapter 1: Fun with Fonts and Colors
Working with FontsUsing font namesUsing font stylesSetting a component's fontGetting a list of available fontsViewing a program that plays with fontsWorking with ColorCreating colorsUsing system colorsSetting the colors of Swing componentsUsing a color chooser
Chapter 2: Drawing Shapes
Getting a Graphics ContextDrawing ShapesTweaking a drawn shapeSeeing how a graphics program creates shapesCreating ShapesCreating linesCreating rectanglesCreating ellipsesCreating arcsLooking at the ShapeMaker programFilling ShapesDrawing transparentlyUsing a gradient fillRotating and TranslatingThe translate methodThe rotate methodDrawing TextLetting the User Draw on a Component
Chapter 3: Using Images and Sound
Using ImagesUsing the ImageIcon ClassUsing ImageIcon in a Swing applicationUsing ImageIcon in an appletUsing the Image ClassCreating an Image objectDrawing an Image objectViewing an Image examplePlaying Sounds and Making Music
Chapter 4: Animation and Game Programming
Working with SpritesAnimating a spriteCreating an animation appletUnderstanding Double BufferingBouncing the BallBouncing a Bunch of BallsCreating a Ball classAnimating random ballsCreating Collidable BallsPlaying Games
About the Author
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Content preview from Java All-in-One For Dummies, 4th Edition

Chapter 6

Using the Object and Class Classes

In This Chapter

Using the toString method

Implementing the equals method

Trying out the clone method

Understanding the Class class

In this chapter, you find out how to use two classes of the Java API that are important to object-oriented programming:

The Object class, which every other class inherits — including all the classes in the Java API and any classes you create yourself
The Class class, which is used to get information about an object's type

If I could, I'd plant a huge Technical Stuff icon on this entire chapter. All this stuff is a bit on the technical side, and many Java programmers get by for years without understanding or using it. Still, I recommend that you read this chapter carefully. Even if it all doesn't sink in, it may help explain why some things in Java don't work quite the way you think they should, and the information in this chapter may someday help you program your way out of a difficult corner.

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Java All-in-One For Dummies, 4th Edition

by Doug Lowe

Using the Object and Class Classes

The Mother ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.