Java Program

Java Program

First Java Program-Example 1

/*This is a simple java program*/

class Example

{

  public static void main (String args[])

  {

  System.out.println (“This is a simple Java program”);

  }

}

Simple Java Program-Some important points

üpublic: Access specifier. main() must be made 

public, since it must be called by code defined 

outside it’s class.

üStatic: It is required because main() is called

 without creating an object of it’s class.

üString args[]: An array of objects of type String

 class. Each object of type string contains a 

character string. It is used to manipulate command

 line argument.

üJava is case sensitive.

üSystem           predefined class that refers to

 system.

  out           It is static data member of System class

  println()      It is a member of out object.

JRE and JDK

üJRE: J2SE Runtime Environment

üprovides

ülibraries,

üJava virtual machine,

üother components necessary for you to run

applets and applications

üJDK: J2SE Development Kit

üincludes

üJRE

ücommand-line development tools such as 

compilers and debuggers