Java Classes and Objects - W3Schools

Create a class named " Main " with a variable x: public class Main { int x = 5; }. Remember from the Java Syntax chapter that a class should always start ... 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JavaQuiz JavaCertificate JavaClassesandObjects ❮Previous Next❯ JavaClasses/Objects Javaisanobject-orientedprogramminglanguage. EverythinginJavaisassociatedwithclassesandobjects,alongwithitsattributesand methods.Forexample:inreallife,acarisanobject.Thecarhasattributes,suchasweightandcolor,and methods,suchasdriveandbrake. AClassislikeanobjectconstructor,ora"blueprint"forcreatingobjects. CreateaClass Tocreateaclass,usethekeywordclass: Main.java Createaclassnamed"Main"witha variablex: publicclassMain{  intx=5; } RememberfromtheJavaSyntaxchapterthataclassshouldalwaysstartwithanuppercasefirstletter,andthatthenameofthejavafileshouldmatchtheclassname. CreateanObject InJava,anobjectiscreatedfromaclass.Wehavealreadycreatedtheclassnamed Main, sonowwecanusethistocreateobjects. TocreateanobjectofMain, specifytheclassname,followedbytheobjectname,andusethekeywordnew: Example Createanobjectcalled"myObj"andprintthevalueofx: publicclassMain{  intx=5;  publicstaticvoidmain(String[]args){    MainmyObj=newMain();    System.out.println(myObj.x);  } } TryitYourself» MultipleObjects Youcancreatemultipleobjectsofoneclass: Example CreatetwoobjectsofMain: publicclassMain{  intx=5;  publicstaticvoidmain(String[]args){    MainmyObj1=newMain(); //Object1    MainmyObj2=newMain(); //Object2    System.out.println(myObj1.x);    System.out.println(myObj2.x);  } } TryitYourself» UsingMultipleClasses Youcanalsocreateanobjectofaclassandaccessitinanotherclass.This isoftenusedforbetterorganizationofclasses(oneclasshasallthe attributesandmethods,whiletheotherclassholdsthemain()method(codeto beexecuted)). Rememberthatthenameofthejavafileshouldmatchtheclassname.Inthis example,wehavecreatedtwofilesinthesamedirectory/folder: Main.java Second.java Main.java publicclassMain{  intx=5; } Second.java classSecond{  publicstaticvoidmain(String[]args){    MainmyObj=newMain();    System.out.println(myObj.x);  } } Whenbothfileshavebeencompiled: C:\Users\YourName>javacMain.java C:\Users\YourName>javacSecond.java RuntheSecond.javafile: C:\Users\YourName>javaSecond Andtheoutputwillbe: 5 TryitYourself» Youwilllearnmuchmoreaboutclassesandobjectsinthenextchapters. TestYourselfWithExercises Exercise: CreateanobjectofMyClasscalledmyObj. =new(); SubmitAnswer» StarttheExercise ❮Previous Next❯ NEW WejustlaunchedW3Schoolsvideos Explorenow COLORPICKER Getcertifiedbycompletingacoursetoday! w3schoolsCERTIFIED.2022 Getstarted CODEGAME PlayGame