Thinking in Java， 2nd Edition（编程教程Word原稿）

THINKINGINJAVASECONDEDITIONBRUCEECKELPRESIDENT,MINDVIEW,INCCOMMENTSFROMREADERSMUCHBETTERTHANANYOTHERJAVABOOKIVESEENMAKETHAT“BYANORDEROFMAGNITUDE”VERYCOMPLETE,WITHEXCELLENTRIGHTTOTHEPOINTEXAMPLESANDINTELLIGENT,NOTDUMBEDDOWN,EXPLANATIONSINCONTRASTTOMANYOTHERJAVABOOKSIFOUNDITTOBEUNUSUALLYMATURE,CONSISTENT,INTELLECTUALLYHONEST,WELLWRITTENANDPRECISEIMHO,ANIDEALBOOKFORSTUDYINGJAVAANATOLYVOROBEY,TECHNIONUNIVERSITY,HAIFA,ISRAELONEOFTHEABSOLUTELYBESTPROGRAMMINGTUTORIALSIVESEENFORANYLANGUAGEJOAKIMZIEGLER,FIXSYSOPTHANKYOUFORYOURWONDERFUL,WONDERFULBOOKONJAVADRGAVINPILLAY,REGISTRAR,KINGEDWARDVIIIHOSPITAL,SOUTHAFRICATHANKYOUAGAINFORYOURAWESOMEBOOKIWASREALLYFLOUNDERINGBEINGANONCPROGRAMMER,BUTYOURBOOKHASBROUGHTMEUPTOSPEEDASFASTASICOULDREADITITSREALLYCOOLTOBEABLETOUNDERSTANDTHEUNDERLYINGPRINCIPLESANDCONCEPTSFROMTHESTART,RATHERTHANHAVINGTOTRYTOBUILDTHATCONCEPTUALMODELTHROUGHTRIALANDERRORHOPEFULLYIWILLBEABLETOATTENDYOURSEMINARINTHENOTTOODISTANTFUTURERANDALLRHAWLEY,AUTOMATIONTECHNICIAN,ELILILLYWHYITWASDESIGNEDTHEWAYITWAS,WHYITWORKSTHEWAYITDOES,WHYITSOMETIMESDOESNTWORK,WHYITSBETTERTHANC,WHYITSNOTALTHOUGHITALSODOESAGOODJOBOFTEACHINGTHEWHATANDHOWOFTHELANGUAGE,THINKINGINJAVAISDEFINITELYTHETHINKINGPERSONSCHOICEINAJAVABOOKROBERTSSTEPHENSONTHANKSFORWRITINGAGREATBOOKTHEMOREIREADITTHEBETTERILIKEITMYSTUDENTSLIKEIT,TOOCHUCKIVERSONIJUSTWANTTOCOMMENDYOUFORYOURWORKONTHINKINGINJAVAITISPEOPLELIKEYOUTHATDIGNIFYTHEFUTUREOFTHEINTERNETANDIJUSTWANTTOTHANKYOUFORYOUREFFORTITISVERYMUCHAPPRECIATEDPATRICKBARRELL,NETWORKOFFICERMAMCO,QAFMFGINCMOSTOFTHEJAVABOOKSOUTTHEREAREFINEFORASTART,ANDMOSTJUSTHAVEBEGINNINGSTUFFANDALOTOFTHESAMEEXAMPLESYOURSISBYFARTHEBESTADVANCEDTHINKINGBOOKIVESEENPLEASEPUBLISHITSOONIALSOBOUGHTTHINKINGINCJUSTBECAUSEIWASSOIMPRESSEDWITHTHINKINGINJAVAGEORGELAFRAMBOISE,LIGHTWORXTECHNOLOGYCONSULTING,INCIWROTETOYOUEARLIERABOUTMYFAVORABLEIMPRESSIONSREGARDINGYOURTHINKINGINCABOOKTHATSTANDSPROMINENTLYONMYSHELFHEREATWORKANDTODAYIVEBEENABLETODELVEINTOJAVAWITHYOUREBOOKINMYVIRTUALHAND,ANDIMUSTSAYINMYBESTCHEVYCHASEFROMMODERNPROBLEMS“ILIKEIT”VERYINFORMATIVEANDEXPLANATORY,WITHOUTREADINGLIKEADRYTEXTBOOKYOUCOVERTHEMOSTIMPORTANTYETTHELEASTCOVEREDCONCEPTSOFJAVADEVELOPMENTTHEWHYSSEANBRADYYOUREXAMPLESARECLEARANDEASYTOUNDERSTANDYOUTOOKCAREOFMANYIMPORTANTDETAILSOFJAVATHATCANTBEFOUNDEASILYINTHEWEAKJAVADOCUMENTATIONANDYOUDONTWASTETHEREADERSTIMEWITHTHEBASICFACTSAPROGRAMMERALREADYKNOWSKAIENGERT,INNOVATIVESOFTWARE,GERMANYIMAGREATFANOFYOURTHINKINGINCANDHAVERECOMMENDEDITTOASSOCIATESASIGOTHROUGHTHEELECTRONICVERSIONOFYOURJAVABOOK,IMFINDINGTHATYOUVERETAINEDTHESAMEHIGHLEVELOFWRITINGTHANKYOUPETERRNEUWALDVERYWELLWRITTENJAVABOOKITHINKYOUVEDONEAGREATJOBONITASTHELEADEROFACHICAGOAREAJAVASPECIALINTERESTGROUP,IVEFAVORABLYMENTIONEDYOURBOOKANDWEBSITESEVERALTIMESATOURRECENTMEETINGSIWOULDLIKETOUSETHINKINGINJAVAASTHEBASISFORAPARTOFEACHMONTHLYSIGMEETING,INWHICHWEREVIEWANDDISCUSSEACHCHAPTERINSUCCESSIONMARKERTESIREALLYAPPRECIATEYOURWORKANDYOURBOOKISGOODIRECOMMENDITHERETOOURUSERSANDPHDSTUDENTSHUGUESLEROY/IRISAINRIARENNESFRANCE,HEADOFSCIENTIFICCOMPUTINGANDINDUSTRIALTRANFERTOK,IVEONLYREADABOUT40PAGESOFTHINKINGINJAVA,BUTIVEALREADYFOUNDITTOBETHEMOSTCLEARLYWRITTENANDPRESENTEDPROGRAMMINGBOOKIVECOMEACROSSANDIMAWRITER,MYSELF,SOIAMPROBABLYALITTLECRITICALIHAVETHINKINGINCONORDERANDCANTWAITTOCRACKITIMFAIRLYNEWTOPROGRAMMINGANDAMHITTINGLEARNINGCURVESHEADONEVERYWHERESOTHISISJUSTAQUICKNOTETOSAYTHANKSFORYOUREXCELLENTWORKIHADBEGUNTOBURNALITTLELOWONENTHUSIASMFROMSLOGGINGTHROUGHTHEMUCKY,MURKYPROSEOFMOSTCOMPUTERBOOKSEVENONESTHATCAMEWITHGLOWINGRECOMMENDATIONSIFEELAWHOLELOTBETTERNOWGLENNBECKER,EDUCATIONALTHEATREASSOCIATIONTHANKYOUFORMAKINGYOURWONDERFULBOOKAVAILABLEIHAVEFOUNDITIMMENSELYUSEFULINFINALLYUNDERSTANDINGWHATIEXPERIENCEDASCONFUSINGINJAVAANDCREADINGYOURBOOKHASBEENVERYSATISFYINGFELIXBIZAOUI,TWINOAKSINDUSTRIES,LOUISA,VAIMUSTCONGRATULATEYOUONANEXCELLENTBOOKIDECIDEDTOHAVEALOOKATTHINKINGINJAVABASEDONMYEXPERIENCEWITHTHINKINGINC,ANDIWASNOTDISAPPOINTEDJACOVANDERMERWE,SOFTWARESPECIALIST,DATAFUSIONSYSTEMSLTD,STELLENBOSCH,SOUTHAFRICATHISHASTOBEONEOFTHEBESTJAVABOOKSIVESEENEFPRITCHARD,SENIORSOFTWAREENGINEER,CAMBRIDGEANIMATIONSYSTEMSLTD,UNITEDKINGDOMYOURBOOKMAKESALLTHEOTHERJAVABOOKSIVEREADORFLIPPEDTHROUGHSEEMDOUBLYUSELESSANDINSULTINGBRETTGPORTER,SENIORPROGRAMMER,ARTTHEYLLCLEANUPPOLLUTIONANDINGENERALALLOWUSTOMASTERTHEMANIPULATIONOFTHEPHYSICALWORLDFORAFRACTIONOFWHATITCOSTSNOWICLAIMEDTHATITWOULDMAKETHECOMPUTERREVOLUTIONLOOKSMALLINCOMPARISONTHENIREALIZEDIWASMAKINGAMISTAKECOMMONTOSCIENCEFICTIONWRITERSGETTINGLOSTINTHETECHNOLOGYWHICHISOFCOURSEEASYTODOINSCIENCEFICTIONANEXPERIENCEDWRITERKNOWSTHATTHESTORYISNEVERABOUTTHETHINGSITSABOUTTHEPEOPLEGENETICSWILLHAVEAVERYLARGEIMPACTONOURLIVES,BUTIMNOTSOSUREITWILLDWARFTHECOMPUTERREVOLUTIONWHICHENABLESTHEGENETICREVOLUTIONORATLEASTTHEINFORMATIONREVOLUTIONINFORMATIONISABOUTTALKINGTOEACHOTHERYES,CARSANDSHOESANDESPECIALLYGENETICCURESAREIMPORTANT,BUTINTHEENDTHOSEAREJUSTTRAPPINGSWHATTRULYMATTERSISHOWWERELATETOTHEWORLDANDSOMUCHOFTHATISABOUTCOMMUNICATIONTHISBOOKISACASEINPOINTAMAJORITYOFFOLKSTHOUGHTIWASVERYBOLDORALITTLECRAZYTOPUTTHEENTIRETHINGUPONTHEWEB“WHYWOULDANYONEBUYIT”THEYASKEDIFIHADBEENOFAMORECONSERVATIVENATUREIWOULDNTHAVEDONEIT,BUTIREALLYDIDNTWANTTOWRITEANOTHERCOMPUTERBOOKINTHESAMEOLDWAYIDIDNTKNOWWHATWOULDHAPPENBUTITTURNEDOUTTOBETHESMARTESTTHINGIVEEVERDONEWITHABOOKFORONETHING,PEOPLESTARTEDSENDINGINCORRECTIONSTHISHASBEENANAMAZINGPROCESS,BECAUSEFOLKSHAVELOOKEDINTOEVERYNOOKANDCRANNYANDCAUGHTBOTHTECHNICALANDGRAMMATICALERRORS,ANDIVEBEENABLETOELIMINATEBUGSOFALLSORTSTHATIKNOWWOULDHAVEOTHERWISESLIPPEDTHROUGHPEOPLEHAVEBEENSIMPLYTERRIFICABOUTTHIS,VERYOFTENSAYING“NOW,IDONTMEANTHISINACRITICALWAY”ANDTHENGIVINGMEACOLLECTIONOFERRORSIMSUREINEVERWOULDHAVEFOUNDIFEELLIKETHISHAS2THINKINGINJAVAWWWBRUCEECKELCOMBEENAKINDOFGROUPPROCESSANDITHASREALLYMADETHEBOOKINTOSOMETHINGSPECIALBUTTHENISTARTEDHEARING“OK,FINE,ITSNICEYOUVEPUTUPANELECTRONICVERSION,BUTIWANTAPRINTEDANDBOUNDCOPYFROMAREALPUBLISHER”ITRIEDVERYHARDTOMAKEITEASYFOREVERYONETOPRINTITOUTINANICELOOKINGFORMATBUTTHATDIDNTSTEMTHEDEMANDFORTHEPUBLISHEDBOOKMOSTPEOPLEDONTWANTTOREADTHEENTIREBOOKONSCREEN,ANDHAULINGAROUNDASHEAFOFPAPERS,NOMATTERHOWNICELYPRINTED,DIDNTAPPEALTOTHEMEITHERPLUS,ITHINKITSNOTSOCHEAPINTERMSOFLASERPRINTERTONERITSEEMSTHATTHECOMPUTERREVOLUTIONWONTPUTPUBLISHERSOUTOFBUSINESS,AFTERALLHOWEVER,ONESTUDENTSUGGESTEDTHISMAYBECOMEAMODELFORFUTUREPUBLISHINGBOOKSWILLBEPUBLISHEDONTHEWEBFIRST,ANDONLYIFSUFFICIENTINTERESTWARRANTSITWILLTHEBOOKBEPUTONPAPERCURRENTLY,THEGREATMAJORITYOFALLBOOKSAREFINANCIALFAILURES,ANDPERHAPSTHISNEWAPPROACHCOULDMAKETHEPUBLISHINGINDUSTRYMOREPROFITABLETHISBOOKBECAMEANENLIGHTENINGEXPERIENCEFORMEINANOTHERWAYIORIGINALLYAPPROACHEDJAVAAS“JUSTANOTHERPROGRAMMINGLANGUAGE,”WHICHINMANYSENSESITISBUTASTIMEPASSEDANDISTUDIEDITMOREDEEPLY,IBEGANTOSEETHATTHEFUNDAMENTALINTENTIONOFTHISLANGUAGEISDIFFERENTFROMALLTHEOTHERLANGUAGESIHAVESEENPROGRAMMINGISABOUTMANAGINGCOMPLEXITYTHECOMPLEXITYOFTHEPROBLEMYOUWANTTOSOLVE,LAIDUPONTHECOMPLEXITYOFTHEMACHINEINWHICHITISSOLVEDBECAUSEOFTHISCOMPLEXITY,MOSTOFOURPROGRAMMINGPROJECTSFAILANDYET,OFALLTHEPROGRAMMINGLANGUAGESOFWHICHIAMAWARE,NONEOFTHEMHAVEGONEALLOUTANDDECIDEDTHATTHEIRMAINDESIGNGOALWOULDBETOCONQUERTHECOMPLEXITYOFDEVELOPINGANDMAINTAININGPROGRAMS1OFCOURSE,MANYLANGUAGEDESIGNDECISIONSWEREMADEWITHCOMPLEXITYINMIND,BUTATSOMEPOINTTHEREWEREALWAYSSOMEOTHERISSUESTHATWERECONSIDEREDESSENTIALTOBEADDEDINTOTHEMIXINEVITABLY,THOSEOTHERISSUESAREWHATCAUSEPROGRAMMERSTOEVENTUALLY“HITTHEWALL”WITHTHATLANGUAGEFOREXAMPLE,CHADTOBEBACKWARDSCOMPATIBLEWITHCTOALLOWEASYMIGRATIONFORCPROGRAMMERS,ASWELLAS1ITAKETHISBACKONTHE2NDEDITIONIBELIEVETHATTHEPYTHONLANGUAGECOMESCLOSESTTODOINGEXACTLYTHATSEEWWWPYTHONORGPREFACE3EFFICIENTTHOSEAREBOTHVERYUSEFULGOALSANDACCOUNTFORMUCHOFTHESUCCESSOFC,BUTTHEYALSOEXPOSEEXTRACOMPLEXITYTHATPREVENTSSOMEPROJECTSFROMBEINGFINISHEDCERTAINLY,YOUCANBLAMEPROGRAMMERSANDMANAGEMENT,BUTIFALANGUAGECANHELPBYCATCHINGYOURMISTAKES,WHYSHOULDNTITASANOTHEREXAMPLE,VISUALBASICVBWASTIEDTOBASIC,WHICHWASNTREALLYDESIGNEDTOBEANEXTENSIBLELANGUAGE,SOALLTHEEXTENSIONSPILEDUPONVBHAVEPRODUCEDSOMETRULYHORRIBLEANDUNMAINTAINABLESYNTAXPERLISBACKWARDSCOMPATIBLEWITHAWK,SED,GREP,ANDOTHERUNIXTOOLSITWASMEANTTOREPLACE,ANDASARESULTISOFTENACCUSEDOFPRODUCING“WRITEONLYCODE”THATIS,AFTERAFEWMONTHSYOUCANTREADITONTHEOTHERHAND,C,VB,PERL,ANDOTHERLANGUAGESLIKESMALLTALKHADSOMEOFTHEIRDESIGNEFFORTSFOCUSEDONTHEISSUEOFCOMPLEXITYANDASARESULTAREREMARKABLYSUCCESSFULINSOLVINGCERTAINTYPESOFPROBLEMSWHATHASIMPRESSEDMEMOSTASIHAVECOMETOUNDERSTANDJAVAISWHATSEEMSLIKEANUNFLINCHINGGOALOFREDUCINGCOMPLEXITYFORTHEPROGRAMMERASIFTOSAY“WEDONTCAREABOUTANYTHINGEXCEPTREDUCINGTHETIMEANDDIFFICULTYOFPRODUCINGROBUSTCODE”INTHEEARLYDAYS,THISGOALHASRESULTEDINCODETHATDOESNTRUNVERYFASTALTHOUGHTHEREHAVEBEENMANYPROMISESMADEABOUTHOWQUICKLYJAVAWILLSOMEDAYRUNBUTITHASINDEEDPRODUCEDAMAZINGREDUCTIONSINDEVELOPMENTTIMEHALFORLESSOFTHETIMETHATITTAKESTOCREATEANEQUIVALENTCPROGRAMTHISRESULTALONECANSAVEINCREDIBLEAMOUNTSOFTIMEANDMONEY,BUTJAVADOESNTSTOPTHEREITGOESONTOWRAPALLTHECOMPLEXTASKSTHATHAVEBECOMEIMPORTANT,SUCHASMULTITHREADINGANDNETWORKPROGRAMMING,INLANGUAGEFEATURESORLIBRARIESTHATCANATTIMESMAKETHOSETASKSTRIVIALANDFINALLY,ITTACKLESSOMEREALLYBIGCOMPLEXITYPROBLEMSCROSSPLATFORMPROGRAMS,DYNAMICCODECHANGES,ANDEVENSECURITY,EACHOFWHICHCANFITONYOURCOMPLEXITYSPECTRUMANYWHEREFROM“IMPEDIMENT”TO“SHOWSTOPPER”SODESPITETHEPERFORMANCEPROBLEMSWEVESEEN,THEPROMISEOFJAVAISTREMENDOUSITCANMAKEUSSIGNIFICANTLYMOREPRODUCTIVEPROGRAMMERSONEOFTHEPLACESISEETHEGREATESTIMPACTFORTHISISONTHEWEBNETWORKPROGRAMMINGHASALWAYSBEENHARD,ANDJAVAMAKESITEASYANDTHEJAVALANGUAGEDESIGNERSAREWORKINGONMAKINGITEVENEASIERNETWORKPROGRAMMINGISHOWWETALKTOEACHOTHERMOREEFFECTIVELYANDCHEAPERTHANWEEVERHAVEWITHTELEPHONESEMAILALONEHASREVOLUTIONIZEDMANY4THINKINGINJAVAWWWBRUCEECKELCOMBUSINESSESASWETALKTOEACHOTHERMORE,AMAZINGTHINGSBEGINTOHAPPEN,POSSIBLYMOREAMAZINGEVENTHANTHEPROMISEOFGENETICENGINEERINGINALLWAYSCREATINGTHEPROGRAMS,WORKINGINTEAMSTOCREATETHEPROGRAMS,BUILDINGUSERINTERFACESSOTHEPROGRAMSCANCOMMUNICATEWITHTHEUSER,RUNNINGTHEPROGRAMSONDIFFERENTTYPESOFMACHINES,ANDEASILYWRITINGPROGRAMSTHATCOMMUNICATEACROSSTHEINTERNETJAVAINCREASESTHECOMMUNICATIONBANDWIDTHBETWEENPEOPLEITHINKTHATPERHAPSTHERESULTSOFTHECOMMUNICATIONREVOLUTIONWILLNOTBESEENFROMTHEEFFECTSOFMOVINGLARGEQUANTITIESOFBITSAROUNDWESHALLSEETHETRUEREVOLUTIONBECAUSEWEWILLALLBEABLETOTALKTOEACHOTHERMOREEASILYONEONONE,BUTALSOINGROUPSAND,ASAPLANETIVEHEARDITSUGGESTEDTHATTHENEXTREVOLUTIONISTHEFORMATIONOFAKINDOFGLOBALMINDTHATRESULTSFROMENOUGHPEOPLEANDENOUGHINTERCONNECTEDNESSJAVAMAYORMAYNOTBETHETOOLTHATFOMENTSTHATREVOLUTION,BUTATLEASTTHEPOSSIBILITYHASMADEMEFEELLIKEIMDOINGSOMETHINGMEANINGFULBYATTEMPTINGTOTEACHTHELANGUAGEPREFACETOTHE2NDEDITIONPEOPLEHAVEMADEMANY,MANYWONDERFULCOMMENTSABOUTTHEFIRSTEDITIONOFTHISBOOK,WHICHHASNATURALLYBEENVERYPLEASANTFORMEHOWEVER,EVERYNOWANDTHENSOMEONEWILLHAVECOMPLAINTS,ANDFORSOMEREASONONECOMPLAINTTHATCOMESUPPERIODICALLYIS“THEBOOKISTOOBIG”INMYMINDITISFAINTDAMNATIONINDEEDIF“TOOMANYPAGES”ISYOURONLYCOMPLAINTONEISREMINDEDOFTHEEMPEROROFAUSTRIASCOMPLAINTABOUTMOZARTSWORK“TOOMANYNOTES”NOTTHATIAMINANYWAYTRYINGTOCOMPAREMYSELFTOMOZARTINADDITION,ICANONLYASSUMETHATSUCHACOMPLAINTCOMESFROMSOMEONEWHOISYETTOBEACQUAINTEDWITHTHEVASTNESSOFTHEJAVALANGUAGEITSELF,ANDHASNOTSEENTHERESTOFTHEBOOKSONTHESUBJECTFOREXAMPLE,MYFAVORITEREFERENCEISCAYHORSTMANNTWOOFTHEPROJECTSHAVEBEENINTEGRATEDINTOOTHERCHAPTERS,ANDTHERESTWERENOLONGERAPPROPRIATEALSO,THE“DESIGNPATTENS”CHAPTERBECAMETOOBIGANDHASBEENMOVEDINTOABOOKOFITSOWNALSODOWNLOADABLEATTHEWEBSITESO,BYALLRIGHTSTHEBOOKSHOULDBETHINNERBUTALAS,ITISNOTTOBETHEBIGGESTISSUEISTHECONTINUINGDEVELOPMENTOFTHEJAVALANGUAGEITSELF,ANDINPARTICULARTHEEXPANDINGAPISTHATPROMISETOPROVIDESTANDARDINTERFACESFORJUSTABOUTEVERYTHINGYOUDLIKETODOANDIWONTBESURPRISEDTOSEETHE“JTOASTER”APIEVENTUALLYAPPEARCOVERINGALLTHESEAPISISOBVIOUSLYBEYONDTHESCOPEOFTHISBOOKANDISATASKRELEGATEDTOOTHERAUTHORS,BUTSOMEISSUESCANNOTBEIGNOREDTHEBIGGESTOFTHESEINCLUDESERVERSIDEJAVAPRIMARILYSERVLETSMOREONTHATALITTLELATERASIDEFROMADDITIONALSMALLLANGUAGEFEATURESADDEDINJAVA2ANDCORRECTIONSMADETHROUGHOUTTHEBOOK,THEOTHERMAJORCHANGEISINTHECOLLECTIONSCHAPTER9,WHICHNOWFOCUSESONTHEJAVA2COLLECTIONSUSEDTHROUGHOUTTHEBOOKIVEALSOIMPROVEDTHATCHAPTERTOMOREDEEPLYGOINTOSOMEOFTHEIMPORTANTISSUESOFCOLLECTIONS,INPARTICULARHOWAHASH6THINKINGINJAVAWWWBRUCEECKELCOMFUNCTIONWORKSSOTHATYOUCANKNOWHOWTOPROPERLYCREATEONETHEREHAVEBEENOTHERMOVEMENTSANDCHANGES,INCLUDINGAREWRITEOFCHAPTER1,ANDREMOVALOFSOMEAPPENDICESANDOTHERMATERIALTHATICONSIDERNOLONGERNECESSARYFORTHEPRINTEDBOOK,BUTTHOSEARETHEBULKOFTHEMINGENERAL,IVETRIEDTOGOOVEREVERYTHING,REMOVEFROMTHE2NDEDITIONWHATISNOLONGERNECESSARYBUTWHICHSTILLEXISTSINTHEELECTRONICFIRSTEDITION,INCLUDECHANGES,ANDIMPROVEEVERYTHINGICOULDASTHELANGUAGECONTINUESTOCHANGEALBEITNOTQUITEATTHESAMEBREAKNECKPACEASBEFORETHEREWILLNODOUBTBEFURTHEREDITIONSOFTHISBOOKFORTHOSEOFYOUWHOSTILLCANTSTANDTHESIZEOFTHEBOOK,IDOAPOLOGIZEBELIEVEITORNOT,IHAVEWORKEDHARDTOKEEPITSMALLDESPITETHEBULK,IFEELLIKETHEREMAYBEENOUGHALTERNATIVESTOSATISFYYOUFORONETHING,THEBOOKISAVAILABLEELECTRONICALLYFROMTHEWEBSITE,ANDALSOONTHECDROMTHATACCOMPANIESTHISBOOK,SOIFYOUCARRYYOURLAPTOPYOUCANCARRYTHEBOOKONTHATWITHNOEXTRAWEIGHTIFYOUREREALLYINTOSLIMMINGDOWN,THEREAREACTUALLYPALMPILOTVERSIONSOFTHEBOOKFLOATINGAROUNDONEPERSONTOLDMEHEWOULDREADTHEBOOKINBEDONHISPALMWITHTHEBACKLIGHTINGONTOKEEPFROMANNOYINGHISWIFEICANONLYHOPETHATITHELPSSENDHIMTOSLUMBERLANDIFYOUNEEDITONPAPER,IKNOWOFPEOPLEWHOPRINTACHAPTERATATIMEANDCARRYITINTHEIRBRIEFCASETOREADONTHETRAINJAVA2ATTHISWRITING,THERELEASEOFSUNSJAVADEVELOPMENTKITJDK13ISIMMINENT,ANDTHEPROPOSEDCHANGESFORJDK14HAVEBEENPUBLICIZEDALTHOUGHTHESEVERSIONNUMBERSARESTILLINTHE“ONES,”THESTANDARDWAYTOREFERTOANYVERSIONOFTHELANGUAGETHATISJDK12ORGREATERISTOCALLIT“JAVA2”THISINDICATESTHEVERYSIGNIFICANTCHANGESBETWEEN“OLDJAVA”WHICHHADMANYWARTSTHATICOMPLAINEDABOUTINTHEFIRSTEDITIONOFTHISBOOKANDTHISMOREMODERNANDIMPROVEDVERSIONOFTHELANGUAGE,WHICHHASFARFEWERWARTSANDMANYADDITIONSANDNICEDESIGNSTHISBOOKISWRITTENFORJAVA2IHAVETHEGREATLUXURYOFGETTINGRIDOFALLTHEOLDSTUFFANDWRITINGTOONLYTHENEW,IMPROVEDLANGUAGEBECAUSETHEOLDINFORMATIONSTILLEXISTSINTHEELECTRONIC1STEDITIONONTHEWEBANDONTHECDROMWHICHISWHEREYOUCANGOIFYOURESTUCKUSINGAPREJAVA2VERSIONOFTHELANGUAGEALSO,BECAUSEANYONECANFREELYDOWNLOADTHEPREFACE7JDKFROMJAVASUNCOM,ITMEANSTHATBYWRITINGTOJAVA2IMNOTIMPOSINGAFINANCIALHARDSHIPONSOMEONEBYFORCINGTHEMTOUPGRADETHEREISABITOFACATCH,HOWEVERJDK13HASSOMEIMPROVEMENTSTHATIDREALLYLIKETOUSE,BUTTHEVERSIONOFJAVATHATISCURRENTLYBEINGRELEASEDFORLINUXISJDK122LINUXSEEWWWLINUXORGISAVERYIMPORTANTDEVELOPMENTINCONJUNCTIONWITHJAVA,BECAUSEITISFASTBECOMINGTHEMOSTIMPORTANTSERVERPLATFORMOUTTHEREFAST,RELIABLE,ROBUST,SECURE,WELLMAINTAINED,ANDFREE,ATRUEREVOLUTIONINTHEHISTORYOFCOMPUTINGIDONTTHINKWEVEEVERSEENALLOFTHOSEFEATURESINANYTOOLBEFOREANDJAVAHASFOUNDAVERYIMPORTANTNICHEINSERVERSIDEPROGRAMMINGINTHEFORMOFSERVLETS,ATECHNOLOGYTHATISAHUGEIMPROVEMENTOVERTHETRADITIONALCGIPROGRAMMINGTHISISCOVEREDINTHE“DISTRIBUTEDPROGRAMMING”CHAPTERSOALTHOUGHIWOULDLIKETOONLYUSETHEVERYNEWESTFEATURES,ITSCRITICALTHATEVERYTHINGCOMPILESUNDERLINUX,ANDSOWHENYOUUNPACKTHESOURCECODEANDCOMPILEITUNDERTHATOSWITHTHELATESTJDKYOULLDISCOVERTHATEVERYTHINGWILLCOMPILEHOWEVER,YOUWILLFINDTHATIVEPUTNOTESABOUTFEATURESINJDK13HEREANDTHERETHECDROMANOTHERBONUSWITHTHISEDITIONISTHECDROMTHATISPACKAGEDINTHEBACKOFTHEBOOKIVERESISTEDPUTTINGCDROMSINTHEBACKOFMYBOOKSINTHEPASTBECAUSEIFELTTHEEXTRACHARGEFORAFEWKBYTESOFSOURCECODEONTHISENORMOUSCDWASNOTJUSTIFIED,PREFERRINGINSTEADTOALLOWPEOPLETODOWNLOADSUCHTHINGSFROMMYWEBSITEHOWEVER,YOULLSOONSEETHATTHISCDROMISDIFFERENTTHECDDOESCONTAINTHESOURCECODEFROMTHEBOOK,BUTITALSOCONTAINSTHEBOOKINITSENTIRETY,INSEVERALELECTRONICFORMATSMYFAVORITEOFTHESEISTHEHTMLFORMAT,BECAUSEITISFASTANDFULLYINDEXEDYOUJUSTCLICKONANENTRYINTHEINDEXORTABLEOFCONTENTSANDYOUREIMMEDIATELYATTHATPORTIONOFTHEBOOKTHEBULKOFTHE300MEGABYTESOFTHECD,HOWEVER,ISAFULLMULTIMEDIACOURSECALLEDTHINKINGINCFOUNDATIONSFORCIFYOUENCOUNTERAPUZZLEYOULLBEABLETOFEEDITTOYOURMODELANDDEDUCETHEANSWERPREREQUISITESTHISBOOKASSUMESTHATYOUHAVESOMEPROGRAMMINGFAMILIARITYYOUUNDERSTANDTHATAPROGRAMISACOLLECTIONOFSTATEMENTS,THEIDEAOFASUBROUTINE/FUNCTION/MACRO,CONTROLSTATEMENTSSUCHAS“IF”ANDLOOPINGCONSTRUCTSSUCHAS“WHILE,”ETCHOWEVER,YOUMIGHTHAVELEARNEDTHISINMANYPLACES,SUCHASPROGRAMMINGWITHAMACROLANGUAGEORWORKINGWITHATOOLLIKEPERLASLONGASYOUVEPROGRAMMEDTOTHEPOINTWHEREYOUFEELCOMFORTABLEWITHTHEBASICIDEASOFPROGRAMMING,YOULLBEABLETOWORKTHROUGHTHISBOOKOFCOURSE,THEBOOKWILLBEEASIERFORTHECPROGRAMMERSANDMORESOFORTHECPROGRAMMERS,BUTDONTCOUNTYOURSELFOUTIFYOURENOTEXPERIENCEDWITHTHOSELANGUAGESBUTCOME10THINKINGINJAVAWWWBRUCEECKELCOMWILLINGTOWORKHARDALSO,THEMULTIMEDIACDTHATACCOMPANIESTHISBOOKWILLBRINGYOUUPTOSPEEDONTHEBASICCSYNTAXNECESSARYTOLEARNJAVAILLBEINTRODUCINGTHECONCEPTSOFOBJECTORIENTEDPROGRAMMINGOOPANDJAVASBASICCONTROLMECHANISMS,SOYOULLBEEXPOSEDTOTHOSE,ANDTHEFIRSTEXERCISESWILLINVOLVETHEBASICCONTROLFLOWSTATEMENTSALTHOUGHREFERENCESWILLOFTENBEMADETOCANDCLANGUAGEFEATURES,THESEARENOTINTENDEDTOBEINSIDERCOMMENTS,BUTINSTEADTOHELPALLPROGRAMMERSPUTJAVAINPERSPECTIVEWITHTHOSELANGUAGES,FROMWHICH,AFTERALL,JAVAISDESCENDEDIWILLATTEMPTTOMAKETHESEREFERENCESSIMPLEANDTOEXPLAINANYTHINGTHATITHINKANONC/CPROGRAMMERWOULDNOTBEFAMILIARWITHLEARNINGJAVAATABOUTTHESAMETIMETHATMYFIRSTBOOKUSINGCOSBORNE/MCGRAWHILL,1989CAMEOUT,IBEGANTEACHINGTHATLANGUAGETEACHINGPROGRAMMINGLANGUAGESHASBECOMEMYPROFESSIONIVESEENNODDINGHEADS,BLANKFACES,ANDPUZZLEDEXPRESSIONSINAUDIENCESALLOVERTHEWORLDSINCE1989ASIBEGANGIVINGINHOUSETRAININGWITHSMALLERGROUPSOFPEOPLE,IDISCOVEREDSOMETHINGDURINGTHEEXERCISESEVENTHOSEPEOPLEWHOWERESMILINGANDNODDINGWERECONFUSEDABOUTMANYISSUESIFOUNDOUT,BYCHAIRINGTHECTRACKATTHESOFTWAREDEVELOPMENTCONFERENCEFORANUMBEROFYEARSANDLATERTHEJAVATRACK,THATIANDOTHERSPEAKERSTENDEDTOGIVETHETYPICALAUDIENCETOOMANYTOPICSTOOFASTSOEVENTUALLY,THROUGHBOTHVARIETYINTHEAUDIENCELEVELANDTHEWAYTHATIPRESENTEDTHEMATERIAL,IWOULDENDUPLOSINGSOMEPORTIONOFTHEAUDIENCEMAYBEITSASKINGTOOMUCH,BUTBECAUSEIAMONEOFTHOSEPEOPLERESISTANTTOTRADITIONALLECTURINGANDFORMOSTPEOPLE,IBELIEVE,SUCHRESISTANCERESULTSFROMBOREDOM,IWANTEDTOTR