An Introduction to Java

What is Java?

Java is a programming language and a platform.

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

Platform: Any hardware or software environment in which a program runs, is known as a platform.

Where it is used?

According to Sun, 3 billion devices run java. There are many devices where java is currently used. Some of them are as follows:

1. Desktop Applications such as acrobat reader, media player, antivirus etc.
2. Web Applications (websites)
3. Enterprise Applications such as banking applications.
4. Mobile
5. Robotics
6. Games etc.

Features of the Java programming language

1) Simple,Small and familiar 
2) Object oriented 
3) Distributed 
4) Robust 
5) Secure 
6) Platform independent 
7) Portable 
8) Compiled and Interpreted 
9) High performance 
10) Multi-threading and interactive 

1) Simple,Small and familiar 
Java is a simple and small language. The Syntax of java is just like C++, so it is very easy to learn. It is simple because it,
i) does not use header files 
ii) eliminated the use of pointer 
iii)operator overloading are eliminated. 

2) Object oriented 
Java is a pure Object oriented, everything in java is object. All programs and data inside objects and classes 


3) Distributed 
Java has networking facilities. So java can create application on network. 

4) Robust 
Java gives importance to memory management by using the technique called Garbage Collection and Exception handling. 

5) Secure 
since java is used on internet, security is an important issue. A security code is asked before a java code is interpreted on internet. 

6) Platform independent 
Java compiler generates platform independent code called bytecode. 

7) Portable 
The Bytecode generated by java can be used on any machine. So it can be portable. 

8) Compiled and Interpreted 
Generally computer languages are either complied or interpreted. But java combines both compiler and interpreted. 

9) High performance 
The use of bytecode makes the performance high. The speed is also high with comparing C, C++. 

10) Multi-threading and interactive 
Multithreading means handling more than one job at a time. Java supports Multithreading. 

Java Platform

A platform is a combination of hardware and software which creates an environment for the execution of an application. The Java platform provides an environment for developing applications that can be executed on various hardware and OS.

·         JVM is Java Virtual Machine -- the JVM actually runs Java bytecode.

·         JDK is Java Developer Kit -- the JDK is what you need to compile Java source code.

·         JRE is Java Runtime Environment -- is what you need to run a Java program and contains a JVM, among other things.