java

1.  Java source filesendwiththe .javaextension.
 Everyclass iscompiledintoaseparate bytecode file thathasthe same name as the class and
endswiththe .classextension.
 To compile aJava source-code filefromthe commandline,use the javaccommand.
 To run a Java classfrom the commandline,use the javacommand.
 EveryJava program isa set of classdefinitions.The keywordclassintroducesaclassdefinition.
The c
 ontentsof the class are includedinablock.
 A blockbeginswithanopeningbrace ({) andendswitha closingbrace (}).Methodsare
containedina class.
 A Javaprogram must have a mainmethod.The mainmethodisthe entrypointwhere the
program startswhenit isexecuted.
 EverystatementinJavaendswitha semicolon(;),knownasthe statementterminator.
 Reservedwords,orkeywords,have aspecificmeaningtothe compilerandcannotbe usedfor
otherpurposesinthe program.
 In Java,commentsare precededbytwoslashes(//) ona line,calledaline comment,orenclosed
between/*and*/onone or several lines,calledablockcomment.
 Java source programsare case sensitive.