Q) What is “Inheritance”?

A)

->inheritance is the mechanism of new entities acquiring from the exiting entities (it is general statement)

->the mechanism of creating new classes from the existing classes with a “is-a” relationship is known as inheritance.

->newly created class is known as “sub class” or child class”.

Child class     - general term

Sub class        - in java

Derived class - in c++

->already existing class is in known as “super class” or “parent class”

Parent class    - in general

Super class     - in java

Base class       - in c++

->”extends” keyword is used to implement inheritance in java.

Ex:

Class A

{
}//super class

Class B extends A

{

}//sub class

->in the above example A is super class and B is sub class.

Is – a relation done by extends keyword. Here “B to A” contains “is-a” relationship but “A to B” there is no relationship.

 

Here A is super class and B is sub class

And “is-a” relation – this is “getting from” relation, not “getting to

->sub classes acquired properties and behaviour from super classes. I.e. a sub class inherits instance variable and instance methods of the super class.

->constructors are not inherited. Because they are not behaviour of the object. They are specialized methods. So the behaviour of the object only inherited.