book

Think Java, 2nd Edition

by Allen B. Downey, Chris Mayfield

November 2019

Beginner

326 pages

6h 44m

English

O'Reilly Media, Inc.

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The Philosophy Behind the BookObject-Oriented ProgrammingChanges to the Second EditionAbout the AppendixesUsing the Code ExamplesConventions Used in This BookO’Reilly Online LearningHow to Contact UsAcknowledgments
What Is a Computer?What Is Programming?The Hello World ProgramCompiling Java ProgramsDisplaying Two MessagesFormatting Source CodeUsing Escape SequencesWhat Is Computer Science?Debugging ProgramsVocabularyExercises
Declaring VariablesAssigning VariablesMemory DiagramsPrinting VariablesArithmetic OperatorsFloating-Point NumbersRounding ErrorsOperators for StringsCompiler Error MessagesOther Types of ErrorsVocabularyExercises
The System ClassThe Scanner ClassLanguage ElementsLiterals and ConstantsFormatting OutputReading Error MessagesType Cast OperatorsRemainder OperatorPutting It All TogetherThe Scanner BugVocabularyExercises
Defining New MethodsFlow of ExecutionParameters and ArgumentsMultiple ParametersStack DiagramsMath MethodsCompositionReturn ValuesIncremental DevelopmentVocabularyExercises
Relational OperatorsThe if-else StatementChaining and NestingThe switch StatementLogical OperatorsDe Morgan’s LawsBoolean VariablesBoolean MethodsValidating InputExample ProgramVocabularyExercises
The while StatementIncrement and DecrementThe for StatementNested LoopsCharactersWhich Loop to UseString IterationThe indexOf MethodSubstringsString ComparisonString FormattingVocabularyExercises
Creating ArraysAccessing ElementsDisplaying ArraysCopying ArraysTraversing ArraysGenerating Random NumbersBuilding a HistogramThe Enhanced for LoopCounting CharactersVocabularyExercises
Recursive Void MethodsRecursive Stack DiagramsValue-Returning MethodsThe Leap of FaithCounting Up RecursivelyBinary Number SystemRecursive Binary MethodCodingBat ProblemsVocabularyExercises
Primitives Versus ObjectsThe null KeywordStrings Are ImmutableWrapper ClassesCommand-Line ArgumentsArgument ValidationBigInteger ArithmeticIncremental DesignMore GeneralizationVocabularyExercises

Point ObjectsObjects as ParametersObjects as Return ValuesRectangles Are MutableAliasing RevisitedJava Library SourceClass DiagramsScope RevisitedGarbage CollectionMutable Versus ImmutableStringBuilder ObjectsVocabularyExercises
The Time ClassConstructorsValue ConstructorsGetters and SettersDisplaying ObjectsThe toString MethodThe equals MethodAdding TimesVocabularyExercises
Card ObjectsCard toStringClass VariablesThe compareTo MethodCards Are ImmutableArrays of CardsSequential SearchBinary SearchTracing the CodeVocabularyExercises
Decks of CardsShuffling DecksSelection SortMerge SortSubdecksMerging DecksAdding RecursionStatic ContextPiles of CardsPlaying WarVocabularyExercises
CardCollectionInheritanceDealing CardsThe Player ClassThe Eights ClassClass RelationshipsVocabularyExercises
Conway’s Game of LifeThe Cell ClassTwo-Dimensional ArraysThe GridCanvas ClassOther Grid MethodsStarting the GameThe Simulation LoopException HandlingCounting NeighborsUpdating the GridVocabularyExercises
Langton’s AntRefactoringAbstract ClassesUML DiagramVocabularyExercises
Polygon ObjectsAdding ColorRegular PolygonsMore ConstructorsAn Initial DrawingBlinking PolygonsInterfacesEvent ListenersTimersVocabularyExercises
Installing DrJavaDrJava InteractionsCommand-Line InterfaceCommand-Line TestingRunning CheckstyleTracing with a DebuggerTesting with JUnitVocabulary
Reading DocumentationWriting DocumentationJavadoc TagsExample Source FileVocabulary
Creating GraphicsGraphics MethodsExample DrawingVocabularyExercises
Compile-Time ErrorsThe compiler is spewing error messages.I’m getting a weird compiler message, and it won’t go away.I can’t get my program to compile no matter what I do.I did what the compiler told me to do, but it still doesn’t work.Run-Time ErrorsMy program hangs.When I run the program, I get an exception.I added so many print statements I get inundated with output.Logic ErrorsMy program doesn’t work.I’ve got a big, hairy expression and it doesn’t do what I expect.My method doesn’t return what I expect.My print statement isn’t doing anything.I’m really, really stuck and I need help.No, I really need help.I found the bug!

Content preview from Think Java, 2nd Edition

Appendix A. Tools

The steps for compiling, running, and debugging Java code depend on your development environment and operating system. We avoided putting these details in the main text, because they can be distracting. Instead, we provide this appendix with a brief introduction to DrJava—an integrated development environment (IDE) that is helpful for beginners—and other development tools, including Checkstyle for code quality and JUnit for testing.

Installing DrJava

The easiest way to start programming in Java is to use a website that compiles and runs Java code in the browser. Examples include Repl.it, Trinket, JDoodle, and others.

If you are unable to install software on your computer (which is often the case in public schools and Internet cafés), you can use these online development environments for almost everything in this book.

But if you want to compile and run Java programs on your own computer, you will need the following:

The Java Development Kit (JDK), which includes the compiler, the Java Virtual Machine (JVM) that interprets the compiled byte code, and other tools such as Javadoc.
A text editor such as Atom, Notepad++, or Sublime Text, and/or an IDE such as DrJava, Eclipse, jGrasp, or NetBeans.

The JDK we recommend is OpenJDK, an open source implementation of Java SE (Standard Edition). The IDE we recommend is DrJava, which is an open source development environment written in Java (see Figure A-1).

To install OpenJDK, visit the AdoptOpenJDK website. Download and run ...