Wednesday, December 24, 2014

Unicode System

Unicode is a universal international standard character encoding that is capable of representing most of the world's written languages.

Why java uses Unicode System?

Before Unicode, there were many language standards:
  • ASCII (American Standard Code for Information Interchange) for the United States.
  • ISO 8859-1 for Western European Language.
  • KOI-8 for Russian.
  • GB18030 and BIG-5 for chinese, and so on.
This caused two problems:
  1. A particular code value corresponds to different letters in the various language standards.
  2. The encodings for languages with large character sets have variable length.Some common characters are encoded as single bytes, other require two or more byte.
To solve these problems, a new language standard was developed i.e. Unicode System.
In unicode, character holds 2 byte, so java also uses 2 byte for characters.
lowest value:\u0000
highest value:\uFFFF

Monday, December 22, 2014

Java Tutorial

Java Tutorial or Core Java Tutorial or Java Programming Tutorial is a widely used robust technology. Let's start learning of java from basic questions like what is java tutorial, core java, where it is used, what type of applications are created in java and why use java. 

What is Java

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

Java Example

Let's have a quick look at java programming example. A detailed description of hello java example is given in next page.
  1. class Simple{  
  2.     public static void main(String args[]){  
  3.      System.out.println("Hello Java");  
  4.     }  
  5. }  

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 such as, etc.
  3. Enterprise Applications such as banking applications.
  4. Mobile
  5. Embedded System
  6. Smart Card
  7. Robotics
  8. Games etc.

Types of Java Applications

There are mainly 4 type of applications that can be created using java:

1) Standalone Application

It is also known as desktop application or window-based application. An application that we need to install on every machine such as media player, antivirus etc. AWT and Swing are used in java for creating standalone applications.

2) Web Application

An application that runs on the server side and creates dynamic page, is called web application. Currently, servlet, jsp, struts, jsf etc. technologies are used for creating web applications in java.

3) Enterprise Application

An application that is distributed in nature, such as banking applications etc. It has the advantage of high level security, load balancing and clustering. In java, EJB is used for creating enterprise applications.

4) Mobile Application

An application that is created for mobile devices. Currently Android and Java ME are used for creating mobile applications.