Diwali

October 22nd, 2007



 

              Diwali 

Diwali, also called Deepavali (in Tamil - ???????), is a major Indian festival that is very significant in Hinduism. Known as the "Festival of Lights," it symbolizes the victory of good over evil, and lamps (called diyas or kandils) are lit as a sign of celebration and hope for humankind. The lights also reprersent the time when Rama came back from the forest, and all his village lit lamps to welcome him back home. Celebrations focus on lights and lamps, particularly traditional dipa or deeya (earthen lamp, as illustrated). Fireworks are associated with the festival. Diwali is a colloquial name used in North India, while the festival is formally called Deepavali in South India.

Diwali is celebrated for five consecutive days at the end of Hindu month of Ashwayuja. It usually occurs in October/November, and is one of the most popular and eagerly awaited festivals in India. Diwali comes exactly twenty days after Dussehra. Hindus and Sikhs alike regard it as a celebration of life and use the occasion to strengthen family and social relationships. For Hindus it is one of the most important festivals, and beginning of the year in some Hindu calendars. There are several beliefs regarding the origin of the holiday. The most repeated version is that Hindus celebrate Diwali to mark the time when Lord Rama achieved victory over Ravana. Some also view it as the day Krishna defeated the demon Narakasura or in honor of the day Bali went to rule the nether-world, obeying the order of Vishnu. It is also a significant festival for the Sikh faith. In India, Diwali is now considered to be more of a national festival, and the aesthetic aspect of the festival is enjoyed by most Indians regardless of faith.

 

dusshera

October 22nd, 2007



 

           Dusshera

The festival of Dassehra, also known as Vijayadashmi, is one of the fascinating festivals of India and is celebrated with joy and enthusiasm. According to the great Hindu scripture, the Ramayana, Lord Rama performed chandi-puja (holy prayer). This was carried out in order to invoke the blessings of Durga Maa for the killing of Ravana, the ten-headed demon king of Sri Lanka who had abducted Seeta, wife of Lord Rama.

Durga Maa divulged the secret to Rama on how he could slay the great Ravana. Hence upon vanquishing the demon Ravana, Lord Rama with Sita and younger brother Laxmana, returned victorious to his kingdom of Ayodhya on the day which is called ‘Diwali’. Revelers across northern India re-enact the legend at sundown in a performance called the Ramlila, featuring actors dressed as Rama shooting flaming arrows at effigies stuffed with firecrackers.

Dassera day is considered a most auspicious day. It is a time-honored belief that if any new venture is started on this day, it is bound to be successful. Hence, all the undertakings be it laying-in of foundation of a new building, opening of a new commercial establishment or even initiating a child into the world of learning- are started on this day. Also on this day implements of agriculture, manufacturer’s machines, the intellectuals pens, the household articles, the children’s school books are placed before the idol of Durga and worshiped.

 

navratri special

October 16th, 2007



 

       NAVRATRI    

Navratri, the festival of nine nights is dedicated to Goddess Durga and her nine forms. According to the Hindu calendar, Navratri begins from the first day of the bright fortnight of Ashwin which usually coincides with the end of the rainy season.

The nine days have great religious significance as Goddess ¤ Introduction
¤ Rituals
¤ Legends
¤ Celebrations

Durga, the divine mother, had destroyed the evil force (in the form of the demon Mahisashura) during this period.
The festival is celebrated with true devotion and purity all over the country. People from various sections of the society irrespective of caste and creed celebrate this festival by visiting temples and offering pujas at the Mother’s feet.

In some places special puja samarohas are also held by setting the images of Mother Durga on beautifully decorated pandals. Temples dedicated to Shakti also make arrangement for pujas and bratas to mark these nine days as true symbols of devotion and adoration towards the divine mother.

 

Interfaces

September 27th, 2007



  Interfaces  
 
Limitation of Interfaces 
Interfaces have one major limitation: they can define abstract methods and final field, but canot specifyany implementation for these methods. For methods, this means that while writing a method, the body is empty. The classes that implement the interfaces are responsible for specifying, the implementation of these methods. This means that, unlike extending a class, where you implement a method, you must override every in the interfaces.
Creating Interfaces
The syntax for creating an interface is extremely similar to that for creating a class. However, there are a few exceptions. The most significant difference is that none of the methods in your interface may have a body, nor can you declare any variables that will not serve as constants. Neverthless, There are some important things that you may include in an interface defination.
Declaring Interfaces
The syntax for creating interfaces follows:
Interface identifier
{
interface Body
Identifier is the name of the interface and interface Body refers to the abstract methods and static final variables that make up the interface. Because it is assumed that all the methods in an interface are abstract, it isn’t necessary to use the abstract keyword.
 Implementing Interfaces
 Because an Interfaces is a prototype, for a class, you must implement an interface to arrive at a usable class. Implementing an interface is similar to deriving from a class, except that you are required to implements any method defined in the interface. To implement an interface, you have to use the implements keyword.

Computer and education

September 22nd, 2007



  Interfaces  
 
An interfaces is a prototype for a class and is useful and is useful from a logical design perspective. Interfaces are abstract classes that are left completely unimplemented. Completely unimplementely in this case means taht no methods in the class have been implemented. Additionally, interfaces member data is limited to static, final variables, which means that they are constant.
 
The benifit of using interfaces are much the same as the benifits of using abstract classes. Interfaces provide a means to define teh protocols for a class without worrying about  the implementation details. This seemingly simple benifit can make large projects much easier to manage; once interfaces have been designed, the class development can take place without worrying about communication among classes. Another important use of interfaces is the capacity for a class to implement multiple interfaces. The major difference between inheriting multiple interfaces and true multiple inheritance is that the interface approach enables you to inherit only method desriptions, not implementation. If a class implements multiple interfaces, that class must provide all the functionality for the methods, defined in the interfaces. Although this approach is certainly more limiting, than multiple inheritance, it is still a very useful feature. It is this feature, of interfaces that separates them from abstract classes.  

Exception Handling

September 21st, 2007



Exception Handling
Error handling becomes a necessitywhile developing application to account for unexpected situations; like
  •  Running out of memory
  • Resource allocation errors
  • The file does not exist
  • Operands beign manipulated out of prescribed ranges

Exception can be defined as an event that occues during the execution of a program that disrupts the normal flow of execution. When an exception occurs, a program may stop working, we canot afford to have an application that stops working. to manager runtime errors java use a hierarchy of exception classes. The top most class in hierarchy is Throwable. The two classes derived from the Throwable class are "Error" and’exception’. When an error occurs in program the method tha tfinds error throw an exception back to its caller. The calling method then catches the thrown exception and if posible recover from it. Example: on executing this program an exception occurs the name of exception is Java.lang.Array index Out of Bound Exception

The Final Keyword

September 20th, 2007



The Final Keyword
The java programming language allows to apply final keywords with classes, methods and variable.
 
  1.  A final class cannot be inherited. E.g. final class employee.
  2. A final method cannot be overriden by subclass. This is done for security reason. If the method has a implementation that should not be changed and is critical to the consistent stage of the object should be marked as final. Method marked as static or private are final automatically because they cannot be notified outside of the class.
  3. A final variable is a constant, any attempt to change the value of a final variable cause a compiler error. To create a final variable we can write the statement as: public final MAX VALUE = 50;

Default Access

September 20th, 2007



Default Access
If any access specifies is not declared for data members or function. Then these objects can be accessed only in classes that are members of same package. If a subclass is out of package that class cannot access the objects of the super class not declared with any access specifies.
The java programming language provide the package mechanism as a way to group related classes. Details will be discussed later on. 

Access Specifies

September 20th, 2007



Access specifies
Data hiding is an important feature of object of object oriented programming languages. An excess specifies (access modifier) helps to determine which feature of a class may be used by other classes. Features of classes are the class itself, the data members, and the methods.
 
Java supports three access specifies.
 
  1.  Public
  2. Private
  3. Protected

The Super Keyword

September 20th, 2007



The Super Keyword
When we call an overriden method by using an instance of subclass it does not invoke superclass method. So how can invoke the superclass overriden method in subclass. For instance in the previous exampleto call the ABC class display class Name () method. We can write the following code in the display class Name () method of xyz class.
 
Public void display class name ( )
{
super.displayclassName ( );
System.out.println ("this is xyz clas");
 
The output of the program will be:-
 
This is Abc class
This is xyz class