Introduction To JAVA

                 
 In this tutorial I will give you a brief introduction on Java. 

 Java is a computer language developed by SUN MICROSYSTEMS in early 90's and named as 'OAK' . It is a purely Object Oriented Programming language developed by James Gausling and Patrik. 

Major features of Java are -

 * Platform Independency

* robustness

* Distributed

* Secure

* Multi-threded

 * Portable and

 * Dynamic etc.

Java works on the paradigm "write once run anywhere" . It works on a framework called as JAVA RUNTIME ENVIRONMENT (JRE), it comes in different edition-

 

1) JAVA STANDARD EDITION(SE)

2)JAVA ENTERPRISE EDITION(EE)

3)JAVA MOBILE EDITION(ME)

                    JAVA STANDARD EDITION(SE) is used to develop client side applications,standard programs and applets which are not used by an enterprise.

                    JAVA ENTERPRISE EDITION(EE)  is used to develop server side applications and to handle projects related to enterprise and include frameworks like STRUTS,BEANS and others.

                    JAVA MICRO EDITION(ME) is used to develop applications for mobile devices such as cell phones,set up boxes and microwave etc.

Java is a free of cost distributed language which can be downloaded from oracle's website. Java works with the help of following methodology-

   JAVA PROGRAM---------->>>>Compile---------->>Class (Byte code)

           

                            (can be used in any environment).

Later on we will be using JDK for developing and compiling Java Programs.

Java Card: 

 A technology that allows small Java-based applications to be run securely on smart cards and similar small-memory devices.

JDK 

 

 JDK consists of a set of separate programs, each invoked from a command line, for developing and testing Java programs. It includes the JRE plus command-line development tools such as compilers and debuggers that are necessary or useful for developing applets and applications.
 

JRE

The JRE provides the libraries, Java virtual machine, and other components necessary for you to run applets and applications written in the Java programming language.

JVM

 The Java virtual machine (JVM) is an abstract computing machine that has an instruction set and manipulates memory at run time. The Java  virtual machine is ported to different platforms to provide hardware- and operating system-independence.

Here is a sample program-

For the compilation of this program , Firstly write this code on notepad then open command prompt 

and then write...

import java.lang.*;

class HelloWorld 

{

public static void main(String[] args)

{

System.out.println("Hello World");

}

}