Inheritance_2

1. What is Is-A relationship in Java?
Ans: Is-A relationship represents Inheritance. It is implemented using the “extends” keyword. It is used for code reusability.


2. How is Inheritance implemented/achieved in Java?
Ans: Inheritance can be implemented or achieved by using two keywords:
extends: extends is a keyword that is used for developing the inheritance between two classes and two interfaces.
implements: implements keyword is used for developing the inheritance between a class and interface.


3. Are constructor and instance initialization block inherited to subclass?

Ans: No, constructor and instance initialization block of the superclass cannot be inherited to its subclass but they are executed while creating 
an object of the subclass.


4. Are static members inherited to subclass in Java?
Ans: Static block cannot be inherited to its subclass.
A static method of superclass is inherited to the subclass as a static member and non-static method is inherited as a non-static member only.


5. What are the advantages of inheritance in Java?
Ans: The advantages of inheritance in java are as follows:
We can minimize the length of duplicate code in an application by putting the common code in the superclass and sharing it amongst several subclasses.
Due to reducing the length of code, the redundancy of the application is also reduced.
Inheritance can also make application code more flexible to change.


6. What are the types of inheritance in Java?
Ans: The various types of inheritance are as follows:
a. Single inheritance
b. Multi-level inheritance
c. Hierarchical inheritance
d. Multiple inheritance
e. Hybrid inheritance


7. What happens if both superclass and subclass have a field with the same name?
Ans: Only subclass members are accessible if an object of subclass is instantiated.


8. Which of the following is correct way of inheriting class A by class B?

a) class B + class A { }
b) class B inherits class A { }
c) class B extends A { }
d) class B extends class A { }

Ans: c


9. How will you prohibit inheritance in Java?
Ans: If you declare a class as final, it cannot be extended. Thus, we can prohibit the inheritance of that class in Java.


10. What is the difference between Inheritance and Composition?
Ans: Inheritance represents Is-A relationship between subclass and its superclass whereas, composition represents Has-A relationship between classes.