java_tutorial.pdf

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1、TutorialsPoint,SimplyEasyLearningJavaTutorialTutorialspoint.comJavaisahigh-levelprogramminglanguageoriginallydevelopedbySunMicrosystemsandreleasedin1995.Javarunsonavarietyofplatforms,suchasWindows,MacOS,andthevariousversionsofUNIX.ThistutorialgivesaninitialpushtostartyouwithJava.Formoredeta

2、ilkindlychecktutorialspoint.com/javaWhatisJava?Javais:ObjectOrientedPlatformindependent:SimpleSecureArchitectural-neutralPortableRobustMulti-threadedInterpretedHighPerformanceDistributedDynamicJavaEnvironmentSetup:JavaSEisfreelyavailablefromthelinkDownloadJava.Soyoudownloadavers

3、ionbasedonyouroperatingsystem.Youcanreferetoinstallationguideforacompletedetail.JavaBasicSyntax:Object-Objectshavestatesandbehaviors.Example:Adoghasstates-color,name,breedaswellasbehaviors-wagging,barking,eating.Anobjectisaninstanceofaclass.Class-Aclasscanbedefinedasatemplate/blueprinttha

4、tdescribethebehaviors/statesthatobjectofitstypesupport.Methods-Amethodisbasicallyabehavior.Aclasscancontainmanymethods.Itisinmethodswherethelogicsarewritten,dataismanipulatedandalltheactionsareexecuted.InstantVariables-Eachobjecthasitsuniquesetofinstantvariables.Anobject.sstateiscreatedby

5、thevaluesassignedtotheseinstantvariables.FirstJavaProgram:LetuslookatasimplecodethatwouldprintthewordsHelloWorld.publicclassMyFirstJavaProgram{1

6、PageTutorialsPoint,SimplyEasyLearning/*Thisismyfirstjavaprogram.*Thiswillprint'HelloWorld'astheoutput*/publicstaticvoidmain(String[]args){System.o

7、ut.println("HelloWorld");//printsHelloWorld}}AboutJavaprograms,itisveryimportanttokeepinmindthefollowingpoints.CaseSensitivity-JavaiscasesensitivewhichmeansidentifierHelloandhellowouldhavedifferentmeaninginJava.ClassNames-ForallclassnamesthefirstlettershouldbeinUpperCase.Ifseveralwordsare

8、usedtoformanameoftheclasseachinnerwordsfirstlettershouldbeinUpperCase.ExampleclassMyFirstJavaClassMethodNames-AllmethodnamesshouldstartwithaLowerCaseletter.Ifseveralwordsareusedtoformthenameofthemethod,theneachinnerword'sfirstlettershouldbeinUpperCase.E