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
List the unexpected quotients in java? 2/3 = 0 3/2 = 1 1/0 = ArithmeticException 0/0 = ArithmeticException 1.0/0.0 = Inf 1.0/0 = Inf 0.0/0.0 = NaN -1.0/0.0

i don''t need any code i need analysis and design only -i need 4 use cases - description - activity diagram -sequence diagram -class diagram - data base diagram

A palindrome is a string that reads the same from both the ends. Given a string S convert it to a palindrome by doing character replacement. Your task is to convert S to palindrome

PS1 emulator for android There is an open source app known as psx4droid i want a developer to solve problems and bugs and doing performance improvement to source code to running

what is join in java Thread

What is constructor chaining and how is it achieved in Java? A child object constructor always first requires to construct its parent (which in turn calls its parent constructo

Program 1. Write a Java program to display the first 20 Fibonacci numbers Program with Fibonacci sequence of first 20 terms Output 2. Write an applet progr

Question: (a) Explain the event handling mechanism using a 'JComboBox' as example. Your answer must clearly indicate the event source, event object and event listener. Also

Explain the char data type in java? A char is a single character in which a letter, a digit, a punctuation mark, a tab, a space or something same. A char literal is a single on

What is a local, member and a class variable? Variables declared within a method are "local" variables. Variables declared within the class i.e not within any methods are "m