Wednesday, 24 June 2015

What Is Java? Where is It Used?

What is Java ?

Java is a programming language developed by James Gasoling at Sun Microsystems.

What is programming language? Do we really need a programming language?

Programming Langauge:

 We humans, communicate with each other using regional languages such as English, Hindi, Telugu, but if you want to communicate with computer, you need special languages such as C, C++, Java and so on. So a programming language is nothing but a language, which will be used to communicate with computers to get the work done.

Using programming languages, we write programs - (sequence of instructions to the computer) - those will be executed by the computer and gives the result. For example, to search for a word in millions of words, you'll need a lot of time, but using programs you can get the result in fractions of seconds.


Coming to Java, Java is an object oriented programming language. If you want to know different types of programming refer here "http://www.speakingcs.com/2014/06/programming-paradigms.html".

A Hello World Program In Java :

class HelloWorld {

 public static void main(String[] args) {
  System.out.println("Hello World");
 }
 
}

Java exhibits a feature called Write Once Run Anywhere (WORA), a feature, which means a compiled java code can run in all platforms that supports java without need of recompilation. In case of C or C++ programs, when ever you want to port to other platform, you need to recompile the source code.

Java programs are typically compiled to byte code that runs on JVMs (Java virtual machine) of various Operating systems.

As of now, Java is one of the most popular programming language in use, with a reported 9 million developers.

There are 3 editions of Java available:

  1. Java Standard Edition (Java SE).
  2. Java Enterprise Edition (Java EE).
  3. Java Micro Edition (Java ME).

For developing Java applications you need JDK (Java Development Kit) and for running java applications you just need JRE (Java Run Time Environment). A JDK will have JRE inside by default. A JVM will be inside of JRE. The differences between JDK, JRE, JVM will be covered in next posts.

You can create different kinds of Applications using Java, those are

1. Standalone Applications - also known as desktop applications, such as media players written in java. JavaSE is used for this purpose.
2. Web Applications - An application that runs on a machine called server and gives response for every request from client in the form of web pages i.e dynamic websites.Java EE is used for this purpose.
3. Enterprise Applications - An application that is distributed in nature, such as Global Trading Applications etc. Springs and Hibernate frameworks are used for enterprise applications.
4. Mobile Applications - An application that runs on mobile devices, such as Andriod.



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