Monday 19 September 2016

Few words

Few words about first Java program

Cool tip
  • Before starting running race in Java coding we need to understand basic things about first java program.
  • So, please be attentive.
  • By using class keyword we will create user defined class.
  • Sample is a user defined class name in program.
  • public is a keyword, it is an access modifier, it is visible to all
  •  static is a keyword.
  •  If we declare any method as static, it is known as static method(we will learn much in upcoming chapter provide link  here).
  • The core advantage of static method is that there is no need to create object to call the static method.
  • void is keyword used for method level to tell the method is nothing returning
main(String[] args)  
  • Program execution starts from main method
  • String[] args is used for command line argument. We will learn it later 
System.out.println()  : 
  • prints statement or data on console.
Flow in simple
  • We need to compile .java program by using javac command.
  • While compiling Compiler will create corresponding .class file for .java program.
  • .class file contains byte code instructions which is not understandable by computer processor to display the output.
  • Now we need to run .class file by using java command.
  • Then while running the  JVM will converts byte code instructions into machine understandable format to see the output.
  • Now its time to celebrate the output of first java program, just have coffee and come back to start running race in coding. 
Thanks for your time.