Introduction To Java.

What is JAVA ?

Java is a programming language and a platform. Java is a high level, robust, object-oriented and secure programming language.

Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has a runtime environment (JRE) and API, it is called a platform. 

             

Let's have a quick look at Java programming example.

class example{  

    public static void main(String args[]){ 

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

         }  

 }  

Features of Java

• Object Oriented Programming (OOP).

It follows all principles of  Object Oriented Programming.

It supports inheritance ,polymorphism & data abstraction.

In java Multiple inheritance is also possible with the help of  "INTERFACE".

• It is both Complied as well as Interpreted.

Most of the programming languages uses either a complier or an interpreter.

Java programs are to be complied to get an intermediate code (BYTE CODE).

Then this byte code is transferred across a network executed by Java Virtual Machine (JVM).

JVM is also know as interpreter of the Byte code.

JVM converts Byte code into Machine code.

• Portable.

Java generate Byte code.

Byte code is Universal code that can be moved anywhere to any platform.

Only JVM needs to be implemented for each platform.

All though the details of JVM differs from platform to platform, all interpret the same Byte code.

• Java is Secure.

Java doesn't use pointer.

Java programs run inside virtual Machines.

Byte code verifier checks illegal code.

Security manager determines what resources a class can access.

Application

Some of the applications of java are as follows:                                     

• Web Applications such as irctc.co.in, javatpoint.com, etc.
• Embedded System
• Enterprise Applications such as banking applications.
• Mobile
• Robotics
• Desktop Applications such as acrobat reader, media player, antivirus, etc.
  
• Smart Card

Types of Java Applications

There are mainly 4 types of applications that can be created using Java programming:

• Web Application

An application that runs on the server side and creates a dynamic page is called a web application. Currently, Servlet, JSP, Struts, Spring, Hibernate, JSF, etc. technologies are used for creating web applications in Java.

• Mobile Application

An application which is created for mobile devices is called a mobile application. Currently, Android and Java ME are used for creating mobile applications.

• Enterprise Application

An application that is distributed in nature, such as banking applications, etc. is called an enterprise application. It has advantages like high-level security, load balancing, and clustering. In Java, EJB is used for creating enterprise applications.

• Standalone Application

Standalone applications are also known as desktop applications or window-based applications. These are traditional software that we need to install on every machine. Examples of standalone application are Media player, antivirus, etc. AWT and Swing are used in Java for creating standalone applications.