Method over ridding method in java, JAVA Programming

Q. Write short on the method over ridding method in java?

Ans. Method over ridding and dynamic binding: We have seen that a method in a super class is inherited by its subclass and is used by the object created by the subclass. Method inheritance enables us to define the method again in the subclass. In the class hierarchy when a instance method the subclass has the same name signature as an instance method (non private) in its super class, then the method in the subclass is said to over ride the method in the super class. When an over ridden method is called from in a subclass, it will always refer to the edition of that method defined by the subclass. The version of the method defined by the super class will be hidden.

Example of method over ridding

Box _ demo java

Class box

{

Int h;

Int w;

Int d;

Box (Int i, Int j, Int k)

{

H = i;

W = j;

D = k;

}

Void show ()

{

System. Out. Println ("box class")

 System. Out. Println (height : " + h)      

System. Out. Println (: "  width+ w)

}

}

Class sub _ box extends box

{

Int i;

Int j;

Int k;

Sub box (Int a, Int b, Int c, Int d, Int e, Int f Int h)

{

Super (d, e, f)

I = a;

J = b;

K = c;

}

Void show ()

{

 

System. Out. Println ("box class")

 System. Out. Println (height : " + h)     

System. Out. Println (: "  width+ w)

}

}

}

Class box _ demo

(

Public static void main (string args[])

{

Sub _ box sb 1 = new sub _ box (10, 20,30, 40, 50, 60);

Sb. Show ();

}

}

Output

Sub _ class of box

Height : 10

Width : 20

Depth : 30

Note when show () method is invoked on an object of type sub _ box the version of show () defined within sub _ box is used, the version of show () method inside sub _ box class over ride declared in box classes.

Application of method over ridding:

Dynamic method binding (dynamic method dispatch or run time binding): method over ridding forms the basic for one java's powerful concept. Dynamic method dispatch is the mechanism by which call to an dynamic method dispatch is an important because this is how java implements run time polymorphism. A super class refers variable can refer to a subclass objects, java uses this fact to resolve calls to over ridden method at run time. When an over ridden method is called through a super class reference, java finds out which version of that method to execute based upon the types of the object being referred to different versions of an over ridden method is called through a super class reference java determines which version of that method to execute based upon the type of the object being referred to at the time of the call referred occurs at this version. Thus this determines is made at run time, when different types of the objects are referred to the different version of an over ridden method of an over ridden method will be called. In other words, it is the kind of the object being referred to (not the type of reference) that determines which version of an over ridden method will be executed. Over ridden method allows java to support run time polymorphism. Polymorphism is essential for OOP for one version. It allows a general class to specify methods that will be common to all of its derivatives while allowing sub classes to define the specific implementation of some of all these methods. By containing inheritance with over ridden methods, a super class can define the general form of method that will be used by all of its sub classes. The ability of existing code libraries to call methods to an instance is a profoundly powerful tool.

Posted Date: 8/1/2012 9:35:42 AM | Location : United States







Related Discussions:- Method over ridding method in java, Assignment Help, Ask Question on Method over ridding method in java, Get Answer, Expert's Help, Method over ridding method in java Discussions

Write discussion on Method over ridding method in java
Your posts are moderated
Related Questions
A servey is done in M.P. by forest department finding different types of species of birds the servey data covered four major cities indore,Bhopal,Gwalior,vidhisa. The result they o

This assignment has two main objectives. It aims to establish a basic familiarity with the Java API (Java Thread class) for creating multithreaded Java application, and the Java ne

Need to develop a 3D rolling alarm clock (Android) Project Description: I want an android app as 3D rolling alarm clock It should have sound effect when setting the alarm

An introduction permits the user to add new methods or attributes to an existing class. This can then be explained to an existing class without having to change the structure of th

I''ve been trying to get this java program to work but im lost and Im stuck ! The factorial of a positive integer N, denoted by N! N!=1*2*...*N Using subprograms and f unctions,c

Plug-in for Adobe after Effects Project Description: We are seeking software engineers to create a plug-in for Adobe after Effects (CS4 and above) that allows 3D extrusions f

Elaborate with examples Vector or Object oriented graphics? Vector or Object-Oriented Graphics treats everything which is drawn as an object. Objects retain their identity afte

Ask1. Storing the Array: Write an application that uses an Array to store 10messages of type String. You will store this Array with 10 messages of your choosing. For example, a mes

What are the different scopes for Java variables? The scope of a Java variable is explained by the context in which the variable is declared. Therefore a java variable can have

The Struts tag libraries are: ? HTML Tags ? Logic Tags ? Template Tags ? Bean Tags ? Tiles Tags ? Nested Tags