book

Think Java

by Allen B. Downey, Chris Mayfield

May 2016

Beginner

249 pages

5h 13m

English

O'Reilly Media, Inc.

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The Philosophy Behind the BookObject-Oriented ProgrammingAppendixesUsing the Code ExamplesConventions Used in This BookO’Reilly SafariHow to Contact UsAcknowledgments
What Is Programming?What Is Computer Science?Programming LanguagesThe Hello World ProgramDisplaying StringsEscape SequencesFormatting CodeDebugging CodeVocabularyExercises
Declaring VariablesAssignmentState DiagramsPrinting VariablesArithmetic OperatorsFloating-Point NumbersRounding ErrorsOperators for StringsCompositionTypes of ErrorsVocabularyExercises
The System ClassThe Scanner ClassProgram StructureInches to CentimetersLiterals and ConstantsFormatting OutputCentimeters to InchesModulus OperatorPutting It All TogetherThe Scanner BugVocabularyExercises
Math MethodsComposition RevisitedAdding New MethodsFlow of ExecutionParameters and ArgumentsMultiple ParametersStack DiagramsReading DocumentationWriting DocumentationVocabularyExercises
Relational OperatorsLogical OperatorsConditional StatementsChaining and NestingFlag VariablesThe return StatementValidating InputRecursive MethodsRecursive Stack DiagramsBinary NumbersVocabularyExercises
Return ValuesWriting MethodsMethod CompositionOverloadingBoolean MethodsJavadoc TagsMore RecursionLeap of FaithOne More ExampleVocabularyExercises
The while StatementGenerating TablesEncapsulation and GeneralizationMore GeneralizationThe for StatementThe do-while Loopbreak and continueVocabularyExercises
Creating ArraysAccessing ElementsDisplaying ArraysCopying ArraysArray LengthArray TraversalRandom NumbersTraverse and CountBuilding a HistogramThe Enhanced for LoopVocabularyExercises
CharactersStrings Are ImmutableString TraversalSubstringsThe indexOf MethodString ComparisonString FormattingWrapper ClassesCommand-Line ArgumentsVocabularyExercises

Point ObjectsAttributesObjects as ParametersObjects as Return TypesMutable ObjectsAliasingThe null KeywordGarbage CollectionClass DiagramsJava Library SourceVocabularyExercises
The Time ClassConstructorsMore ConstructorsGetters and SettersDisplaying ObjectsThe toString MethodThe equals MethodAdding TimesPure Methods and ModifiersVocabularyExercises
Card ObjectsCard toStringClass VariablesThe compareTo MethodCards Are ImmutableArrays of CardsSequential SearchBinary SearchTracing the CodeRecursive VersionVocabularyExercises
The Deck ClassShuffling DecksSelection SortMerge SortSubdecksMerging DecksAdding RecursionVocabularyExercises
Decks and HandsCardCollectionInheritanceDealing CardsThe Player ClassThe Eights ClassClass RelationshipsVocabularyExercises
Installing DrJavaDrJava InteractionsCommand-Line InterfaceCommand-Line TestingRunning CheckstyleTracing with a DebuggerTesting with JUnitVocabulary
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!

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Appendix A. Development 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 well suited 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 jdoodle.com, compilejava.net, tutorialspoint.com, 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 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 simple text editor such as Notepad++ or Sublime Text, and/or an IDE such as DrJava, Eclipse, jGrasp, or NetBeans.

The JDK we recommend is Java SE (Standard Edition), which Oracle makes available for free. The IDE we recommend is DrJava, which is an open-source development environment written in Java (see Figure A-1).

To install the JDK, search the web for “download ...