•
•


TableofContents
Index

JustJava™2SIXTHEDITION
ByPETERvanderLINDEN

Publisher :AddisonWesley
PubDate :June21,2004
ISBN :0-13-148211-4
Pages :848


The#1introductiontoJ2SE1.5and
enterprise/server-sidedevelopment!
Aninternationalbestsellerforeightyears,
JustJava(TM)2isthecomplete,accessible
Javatutorialforworkingprogrammersatall
levels.Fullyupdatedandrevised,thissixth
editionismorethananengagingoverviewof
Java2StandardEdition(J2SE1.5)andits
libraries:it'salsoapracticalintroductionto
today'sbestenterpriseandserver-side
programmingtechniques.JustJava(TM)2,


SixthEdition,reflectsbothJ2SE1.5andthe

latestTomcatandservletspecifications.
Extensivenewcoverageincludes:
Newchaptersongenericsandenumerated
types
NewcoverageofWebservices,with
practicalexamplesusingGoogleand
AmazonWebservices
SimplifiedinteractiveI/Owithprintf()
Autoboxingandunboxingofprimitive
types
Staticimports,foreachloopconstruct,and
othernewlanguagefeatures
PetervanderLindendeliversexpertadvice,
clearexplanations,andcrispsample
programsthroughoutincludingdozensnewto
thisedition.Alongtheway,heintroduces:
Thecorelanguage:syntax,objects,
interfaces,nestedclasses,compiler
secrets,andmuchmore


Keylibraries:dateandcalendar,pattern
matching,networksoftware,mappedI/O,
utilitiesandgenericcollections
Server-sidetechnology:networkserver
systems,acompletetinyHTMLWeb
server,andXMLinJava
EnterpriseJ2EE:SqlandJDBC(TM)
tutorial,servletsandJSPandmuchmore
Client-sideJava:fundamentalsof

JFC/SwingGUIdevelopment,newclass
datasharingdetails
CompanionWebSite
Allthebook'sexamplesandsampleprograms
areavailableat.



•
•


TableofContents
Index

JustJava™2SIXTHEDITION
ByPETERvanderLINDEN

Publisher :AddisonWesley
PubDate :June21,2004
ISBN :0-13-148211-4
Pages :848










Copyright
Preface
Acknowledgments
Part1.Language
Chapter1.WhatCanJavaDoforMe?
WhatJavaDoesforYou:SoftwarePortability




WhyPortabilityMatters




OneSizeDoesn'tFitAll




LanguageandLibraries
SomeLightReliefAJavaDesktopApplication
Chapter2.IntroducingObjects
DownloadingandCompilingJava




WhatIsaClass?





JavaDigitalClockProgram




Exercises



WhatIsanObject?
Summary
SomeLightReliefNapsterandLimeWire
Chapter3.PrimitiveTypes,Wrappers,andBoxing





LiteralValues




char





long




short




double




ObjectWrappersforPrimitives




PerformanceImplicationsofAutoboxing




java.lang.String





StringComparison




boolean
int
byte
LimitedAccuracyofFloatingPointTypes
float
AutoboxingandUnboxing
java.lang.Object
LanguageSupportforStringConcatenation
SomeLightReliefHatlessAtlas
Chapter4.StatementsandComments
OrganizingStatements




ExpressionStatements




LoopingStatements





Comments




Exercises




SelectionStatements
TransferofControlStatements
ReadingtheJavaAPI
SomeLightReliefMiniScribe:TheHardLuckHardDisk
Chapter5.OOPPartIIConstructorsandVisibility
PolymorphismIsaLongWordforaShortTopic




CreatingNewObjects:Constructors




Variable-ArityMethods





HowtheJDKFindsClasses




Exercises



MoreAboutMethods
Packages
AccessModifiers
SomeLightReliefIt'sNotYourFather'sIBM
Chapter6.Static,Final,andEnumeratedTypes




WhatFieldModifierstaticMeans




WhatFieldModifierfinalMeans





StatementsUpdatedforEnumerations




SomeLightReliefTheHauntedZenGardenofApple

WhyEnumerateaType?
MoreComplicatedEnumeratedTypes
Chapter7.Names,Operators,andAccuracy




Keywords




Names




Expressions




Operators





HowAccurateAreCalculations?




WhatHappensonOverflow?




PunctuationTerminology
Identifiers
Arrays
Associativity
WideningandNarrowingConversions
SomeLightReliefFurby'sBrainTransplant
Chapter8.MoreOOPExtendingClasses
Inheritance




Polymorphism





Exercises




TheClassWhoseNameIsClass
SomeLightReliefTheNerdDetectionSystem
Chapter9.Arrays
UnderstandingandCreatingArrays




ArraysofArrays




TheMathPackage




HaveArrayBrackets,WillTravel
SomeLightReliefThinkBig(andSmall)
Chapter10.Exceptions
Run-timeInternals:TheHeap





GarbageCollection




Exceptions




FurtherReading

Run-timeInternals:TheStack
TheAssertStatement
SomeLightReliefMakinganExceptionforYou




Chapter11.Interfaces




WhatProblemDoesanInterfaceSolve?





InterfacesVersusAbstractClasses




WhatProtectedReallyMeans




TheClassDouble




SomeLightReliefTheJava-PoweredToaster

Interfacejava.lang.Comparable
GrantingPermissionThroughanInterfaceCloneable
UsingInterfaceCallbacksforGUIEventHandlers
Exercises
Chapter12.NestedClasses




IntroductiontoNestedClasses





InnerMemberClasses




InnerAnonymousClasses




TheClassCharacter

NestedStaticClasses
InnerLocalClasses
HowInnerClassesAreCompiled
Exercises

SomeLightReliefTheDomesticObfuscatedJavaCodeNon-Competition


Part2.KeyLibraries
Chapter13.DoingSeveralThingsatOnce:Threads




WhatAreThreads?





TheLifecycleofaThread




FourKindsofThreadsProgramming




Chapter14.AdvancedThreadTopics

TwoWaystoObtainaNewThread
ThreadGroups
SomeLightReliefTheMotionSensorSolution
MutuallyExclusiveThreads




CommunicatingMutuallyExclusiveThreads




ThreadLocalStorage





AnAsideonDesignPatterns




Exercises

PipedI/OforThreads
Packagejava.util.concurrent
FurtherReading
SomeLightReliefAreYouCertifiable?IAm.




Chapter15.Explanation<Generics>




TerminologyRefresher:ParametersVersusArguments




WhatGenericCodeLooksLike


TheProblemthatGenericCodeAddresses
GenericInterfaces

BoundsRequiringaTypeParametertoImplementanInterfaceorExtenda
ParentClass
SomeLightReliefOnComputableNumberswithanApplicationtothe

Entscheidungsproblem

Part3.Server-sideJava
Chapter16.Collections






CollectionAPI




Set,HashSet,andSortedSet




WildcardParametersandGenericMethods





GenericMethods




Map,HashMap,andTreeMap




SomeLightReliefEarlyNamesforJava

List,LinkedList,andArrayList
TheCollectionsHelperClass
WildcardingaGenericParameter
SummaryofCollection
Exercises
Chapter17.SimpleInputOutput




GettingtoKnowJavaI/O




TheClassjava.io.File





Output




Input




InputtingASCIICharactersandBinaryValues




FurtherReading




SomeLightReliefTheIllegalPrimeNumber!




DesignPhilosophy

KeyboardI/O
WrappingAdditionalOutputClasses
ReaderWrappers
InputStreamWrappers
Exercises
Chapter18.AdvancedInputOutput
RandomAccessFile
RunningCommandsandGettingOutputFromThem




FormattedStringOutput



WritingObjectstoDisk




NewI/OPackage




FileLocking





Exercises

MemoryMappedI/O
CharsetsandEndian-ness
SomeLightReliefTheIllegalT-shirt!


Part4.ClientJava
Chapter19.RegularExpressions

RegularExpressionsAndPatternMatching




CalendarUtilities




FurtherReading




SomeLightReliefExchangingApplesAndCrays

OtherUtilityClasses
Exercises

Chapter20.GUIBasicsandEventHandling




AllAboutEventHandling




SummaryofEventHandling




SomeLightReliefTheMouseThatRoared

TipsforSlimmingDownHandlerCode
Exercises
Chapter21.JFCandtheSwingPackage




JavaFoundationClasses




SwingThreadsACaution!





MoreAboutSwingComponents




Exercises




AllAboutControls(JComponents)
SwingComponents
FurtherReading
SomeLightReliefTheBibleCode
Chapter22.Containers,Layouts,andAWTLooseEnds
PluggableLookandFeel




AllAboutContainers




TyinguptheLooseEnds




SomeLightReliefSkyViewCafe:AHighQualityApplet

LayoutinaContainer
Exercises





Part5.EnterpriseJava
Chapter23.RelationalDatabasesandSQL



IntroductiontoRelationalDatabases




PrimaryandForeignKeys




NormalForms





DownloadandInstallMckoi




CreatingandPopulatingTables




SubquerySelections




UpdatingValues




SQLPreparedStatementsandStoredProcedures




SomeLightReliefReadingtheDocs

Relationships


RelationalDatabaseGlossary
BasicSQLPrimer
QueryingandRetrievingData
ResultSetofaSELECTQuery
DeletingRecordsandTables
Exercises
Chapter24.JDBC




IntroductiontoJDBC




RunningtheExampleCode




ExecutingSQLStatements




BatchingSQLStatementsandTransactions





CompleteExample




FurtherReading




HeavyLightReliefInWhich"I"SpamMyself

InstallingtheMckoiDatabaseSoftware
ConnectingtotheDatabase
ResultSets
PreparedStatementsandStoredProcedures
DatabaseandResultSetMetadata
Exercises
Chapter25.NetworkinginJava




EverythingYouNeedToKnowaboutTCP/IPbutFailedtoLearninKindergarten





SendingEmailbyJava

AClientSocketinJava
AServerSocketinJava




HTTPandWebBrowsing:RetrievingHTTPPages




AMultithreadedHTTPServer










AMappedI/OHTTPServer
FurtherReading

Exercises
SomeLightRelief500MileLimitonEmail
Chapter26.ServletsandJSP

OverviewofServletsandJSP




WhyUseServlets?




InstallingtheTomcatSoftware




PortsandProtocols




AServletandItsRequest/Response




ResponsetoaServletRequest





ServletOperatingCycleandThreading




JavaBeansinServletsandJSP




FurtherReading




SomeLightReliefUsingJavatoStuffanOnlinePoll

ReleasesandVersions
RunningtheExampleServlets
TheHTMLtoInvokeaServlet
ServletRequest
WritingYourOwnServlet
JavaServerPages
LastWordsonJSP,Beans,andTagLibraries
Exercises
Chapter27.XMLandJava





XMLVersusHTML




TheDocumentTypeDefinition(DTD)




XMLVersionsandGlossary




ReadingXMLWithDOMParsers




ReadinganXMLFileSAXParsers



TheFactoryDesignPattern

SomeRulesofXML
WhatIsXMLUsedFor?
JAXPLibraryContents
AProgramThatUsesaDOMParser

AProgramThatUsesaSAXParser




DesignPatternSummary



OtherJavaXMLNotes



FurtherReading




Exercises



SomeLightReliefViewSourceonKevin'sLife
Chapter28.WebServicesatGoogleandAmazon




WebServicesIntroduction




AmazonWebServices




Conclusions

GoogleWebServices

SomeLightReliefGooglewhacking




AppendixA.DownloadingJava




AppendixB.PowersofTwoTable



Nowit'sHelloWorld
AppendixC.Codesets
Index



Copyright
©2004SunMicrosystems,Inc.
PrintedintheUnitedStatesofAmerica.
4150NetworkCircle,SantaClara,California
95054U.S.A.
LibraryofCongressControlNumber:2004107483
Allrightsreserved.Thisproductandrelateddocumentationare
protectedbycopyrightanddistributedunderlicensesrestricting
itsuse,copying,distribution,anddecompilation.Nopartofthis
productorrelateddocumentationmaybereproducedinany
formbyanymeanswithoutpriorwrittenauthorizationofSun
anditslicensors,ifany.
RESTRICTEDRIGHTSLEGEND:Use,duplication,ordisclosure
bytheUnitedStatesGovernmentissubjecttotherestrictions
setforthinDFARS252.227-7013(c)(1)(ii)andFAR52.227-19.
TheproductsdescribedmaybeprotectedbyoneormoreU.S.
patents,foreignpatents,orpendingapplications.
TRADEMARKSHotJava,Java,JavaDevelopmentKit,J2EE,JPS,
JavaServerPages,EnterpriseJavaBeans,EJB,JDBC,J2SE,
Solaris,SPARC,SunOS,andSunsoftaretrademarksofSun
Microsystems,Inc.Allotherproductsorservicesmentionedin
thisbookarethetrademarksorservicemarksoftheir
respectivecompaniesororganizations.
PrenticeHallPTRoffersexcellentdiscountsonthisbook
whenorderedinquantityforbulkpurchasesorspecial
sales.Formoreinformation,pleasecontactU.S.
CorporateandGovernmentSales,1-800-382-3419,
Forsalesoutsideofthe
U.S.,pleasecontactInternationalSales,1-317-5813793,



AcquisitionsEditor:GregoryG.Doench
EditorialAssistant:RaquelKaplan
ProductionSupervision:JulieB.Nahil
Editor:SolveigHaugland
CoverDesigner:NinaScuderi
ArtDirector:GailCocker-Bogusz
ManufacturingManager:CarolMelville
MarketingManager:ChrisGuzikowski
SunMicrosystemsPressPublisher:MyrnaRivera
Textprintedonrecycledpaper
12345678910CRW0807060504
Firstprinting,June2004

Dedication
Iusedtodedicatethesebookstospecificbrandsofrealale;it
wasalwaysgoodforlunchwiththechairmanwhenItouredthe
brewery.Here'ssomethingdifferent.I'veworkedinthe
computerindustryallmylife,andinthelastfewyearsstarted
teachingprogrammingclassestoo.Youlearnalotwhenyouget
immediatefeedbackabouttopicsthatneedtobeexpressedin
easierpieces.Iwouldliketodedicatethisbooktoallmy
studentspastandpresent,andallmyteachers,youngandold.


Preface
ThefirsteditionofJustJavawasoneoftheearliestbooksto
accompanytheoriginalreleaseofJavain1996.Thelaunchof
Javacoincidedwiththeexplosionofinterestinthewebandthe
netwhich,inturn,drovetechnologyforwardatafranticpace.

Peopletalkedabout"Internettime,"whichmeantthreethings
tomeinSiliconValley:therewasimmensepressuretorapidly
createnewhardwareandsoftwareproducts;everyonewrote
softwaretodisplaystockpricesontheirdesktopsandcell
phones;youwereforgivenfornotshoweringifyoufellasleep
atyourdeskaftermidnightandwokeuptherethenext
morning.Timeshavechanged,butsoftwareproductivity
remainsabigreasonbehindJava'spopularity.
OverthelasteightyearsJavahashadsixmajorreleases,
averagingoneaboutevery18months.Witheachofthese
releases,therehasbeenaneweditionofJustJavatodescribe
andexplainthetechnology.Table1showshowthelanguage
andlibrarieshaveimproved.
Table1.JavachangesfromJDK1.0.2toJava2v1.4
Release

Date

SeeJustJava6th
ed.

Content

JDK1.0.2

Jan1996

Firstgeneralreleaseof Throughoutthebook
thelanguageand
libraries


JDK1.1

Feb1997

Languagechanges:



Instanceinitializers

Chapter5

Arrayinitializers

Chapter9

Nestedclasses

Chapter12


Librarychanges:

JDK1.2
(rebadgedto
Java2)

Dec1998




Delegationbased
event-handlers

Chapter20

I/OReadersand
Writers

Chapter17

Objectserialization

Chapter18

Languagechanges:



strictfp

Chapter7

Weakreferences

Chapter10

Librarychanges:




JavaFoundationand
Swing

Chapter21

Collectionclasses,
JDBCenhancements

Chapter16,23-24

Threadlocalstorage

Chapter14
Throughoutthebook

Java2v1.3

May2000

Performanceandbug
fixes,nosignificant
changes

Java2v1.4

Dec2001

Languagechanges:

Assertstatement
Librarychanges:



Chapter10



Regularexpressions

Chapter19

NewI/O(third
attempt)

Chapter18


Thisisaremarkablepaceofdevelopmentforaprogramming
system,particularlywhenSunkeepssuchanemphasison
backwardcompatibilityandportability.TheJava1.2releasewas
asignificantone,bundlingmajorfunctionalityimprovements
likethecollectionclassesandtheSwingGUIlibrary.Java1.3
and1.4werecomparativelysmaller,although1.4didbringa
newstatement("assert")intothelanguage.
Twoandahalfyearsinthemaking,Java1.5isthebiggest
versionyet.ItisbiggerandmoresignificantthanJDK1.2.Sun
willprobablyrenameJava1.5tosomeawkwardandconfusing
nameusingtwosetsofnumbers,like"Java2Mega-editionv1.5

fab-o-lux".Whatevertheycallit,thinkofJava1.5as"Java3".
Table2showssomeofthesubstantiallanguageadditions.
Table2.Java2v1.5
Release
Java2

Date

Content

Jun2004 Languagechanges:

SeeJustJava6thed.



v1.5
Autoboxingandunboxing

Chapter3

Enumtypes

Chapter6

Generictypes

Chapter15,16

Variable-aritymethods


Chapter5

Staticimport

Chapter6

Enhancedforloop

Chapter4

Covariantreturntypes

Chapter11




Librarychanges:
printf(likeC'sprintf)

Chapter17

java.util.scanner(fourth
attemptatfixingI/O)

Chapter17

java.util.concurrentthread
utilities


Chapter14

javax.xmlXMLsupport
bundled

Chapter27,28

Classdatasharing

Chapter2

CanaddSwingcomponents Chapter21
directlytoaContainer!

Therearealsothetraditionalbug-fix,libraryandperformance
improvements,includingsomeexcitingoptimizationsfor
desktopapplications.
Overtheyears,I'veputalotofhardworkintounlockingthe
changesinJava,soyoudon'thaveto.You'relookingatthe
resultsofthateffort:thesixtheditionofJustJava.
I'mconfidentyou'llfinditeasytoread,andpackedwiththe
informationyouneed.
Ihopethatyou'llwantacopyforyourself.
Butifnot,Iwantyoutoputitbackontheshelf,only(asmy
friendAlanAbelsuggested)inamoreprominentposition.
P.


Acknowledgments

I'mverygratefultothefollowingpeople,whoaresomeofthe
mosttalentedandcreativeindividualsyou'llfind:
GiladBracha
MichaelDavidson
JaneErskine
MarcusGreen
RoedyGreen
TreyHarris
KarstenLentzsch
BobLynch
AleksanderMalinowski
SimonRoberts
RickRoss,whoprovidesfirst-classleadershipat

KerryShetline
RobinSouthgate
LeftyWalkowiak
AllthecowboysandcowgirlsdownontheJavaRanch

TheLimewireteam


TheunsungheroesandheroinesofSun'sJavaandSolaris
groups
Theeditorial,marketing,andproductionteamsatPrentice-Hall
andSunMicrosystemsdeservefullappreciation:
GregDoench,ChrisGuzikowski,JulieNahil,RaquelKaplan,Nina
Scuderi,andSolveigHauglandandhermagiceditingpixies.
Thankstoo,tomywife,family,andfriendshey,ifIwantedmy
studytolookorganized,I'dkeepitthatway,OK?



Part1:Language
Chapter1.WhatCanJavaDoforMe?
Chapter2.IntroducingObjects
Chapter3.PrimitiveTypes,Wrappers,andBoxing
Chapter4.StatementsandComments
Chapter5.OOPPartIIConstructorsandVisibility
Chapter6.Static,Final,andEnumeratedTypes
Chapter7.Names,Operators,andAccuracy
Chapter8.MoreOOPExtendingClasses
Chapter9.Arrays
Chapter10.Exceptions
Chapter11.Interfaces
Chapter12.NestedClasses


Chapter1.WhatCanJavaDoforMe?
WhatJavaDoesforYou
WhyPortabilityMatters
LanguageandLibraries
OneSizeDoesn'tFitAll
SomeLightReliefAJavaDesktopApplication
Javahasbecomeaverypopularprogramminglanguageforthe
kindofmodernsoftwarepeoplewanttowrite.Javabeganasa
researchprojectinsideSunMicrosystems.Theresultswere
postedontheweb,andJavatookofflikeaTitanrocket.Sun
wiselydecidedtonurturethemarketbysharing,andlicensed
thetechnologyacrossthecomputerindustry.Today,Java
compilersandsourcecodeareavailableforfreedownloadfrom

manydifferentorganizations.Justabouttheentirecomputer
industryisbackingJavaenthusiasticallywithproductsand
support.Inthischapterwe'lllookatthereasonsbehindJava's
popularity,andsummarizethekeyfeaturesofthelanguage.
Javaworkswellforwebandserver-basedapplications.Ithas
greatfeatureslikeobject-orientedprogramming,easydatabase
access,andwell-designedGUIsupport.Thelatestrelease,Java
2version1.5,hasperformancetweakstospeedupdesktop
programs.Therearelibrariesforcommunicatingacross
networks,andforencryption.Ithasstrongsecuritybuiltin.
MostprogrammerspickupJavaquickly.Behindallthis,Javais
morethanjustthelatest,mostpopularprogramminglanguage.
Itisawayofcreatingapplicationsthatareindependentofall
hardwareandalloperatingsystems.


WhatJavaDoesforYou:SoftwarePortability
Whatismeantby"applicationsthatareindependentofall
hardwareandoperatingsystems?"Itmeansyoucancompilea
Javaprogramonanysystemandruntheresultingbinary
executablefileonthesameoranyothersystemonaMacintosh,
onWindows98,NT,2K,XP,onSolaris,Linux,BSDoranyofthe
varietiesofUnix,onIBM'smainframeoperatingsystems,oncell
phones,PersonalDigitalAssistants(PDAs),embedded
processors,andevenonsmartcards(creditcardswitha
microprocessorandmemory),asshowninFigure1-1.

Figure1-1.Future-proofsoftware:YourJava
applicationrunsoneverysystem.Nomore
"requiresWindowsXP"or"LinuxPPConly",or

"compiledforMacOSXversion10.5";just"built
withJava,"andyou'redone.

[Viewfullsizeimage]


Youwillevenbeabletorunonfutureoperatingsystem
releases,likeMicrosoft'sLonghorn.Javawillbeportedtoall
futureoperatingsystemsofsignificance.It'salsoafastwayfor
newhardwaretogetsoftwareapplicationsthatwillrunonit.
JavaunlockssoftwarefrombeingcoupledtoanyspecificOS
andhardwareplatform.ThisnewflexibilityhasmadeJavavery
popularwithusers,ITdepartments,andsoftwarevendors.All
threebenefitenormouslyfromsoftwareportability.


WhyPortabilityMatters
Youmightthinkthatsoftwareportabilitydoesnotaffectyou:
yourapplicationsoftwarerunsfineonyourPCtodayandthat's
allyouuse.Andthat'strue,rightupuntilthetimeyouwantto
consideranewordifferentsystem.
Sayyou'reinthemarkettobuyanewdesktopsystem,anda
friendshowsyouthevideo-editing,music,virusresistance,and
digitalpicturecapabilitiesofhisAppleMacintosh.Youconsider
switchingtoaMac.SwitchingGUIsisano-brainerGUIsalldo
essentiallythesamethings,anditonlytakesadayortwoto
re-trainyourfingers.Theproblemistheapps.Youarefaced
withthe"choice"ofwalkingawayfromyourinvestmentinyour
existingPC-onlysoftware,orbuyingyetanotherWindowsPC
thathassomecompatibilitywithyourprevioussystem.Youcan

easilyswitchhardwarefromDelltoH-PorIBM,butthere'sa
softwarebarriertoswitchingfromWindowstosomethingwith
fewersecurityproblems,likeLinuxorMacOS.You'vebeen
lockedin.
WhenyourapplicationprogramsarewritteninJava,youcan
upgradeOSandapplicationsindependently.YoucantryLinux
andstilluseyourfamiliarapplications.Youcanmoveyour
existingJavaprogramstoanynewsystem,andcarryonusing
them.Thisiswhysoftwareportabilitymatterstohomeusers.
Forbusinesses,theproblemisworseandfarmoreexpensive.
Evenifyourwholeorganizationhasstandardizedon,say,
MicrosoftWindowsXP,therehavebeennumerousreleasesover
justthelastdecadeandabit:MS-DOS,Win3.1,Win3.11,
Win95A,Win95B,Win98,98SE,ME,NT3.1,NT3.5,NT3.51,
NT4,2K,multipleservicepacksandrequiredhot-fixes,XP,and
Longhornonthehorizon.Theseplatformshavesubtleand
differentincompatibilitiesamongthem.Evenapplications
runningonasingleplatformhavelimitedinteroperability.Older