Inheritance

Question 1

What is inheritance?

Answer 1

A mechanism where a new class (subclass) inherits properties and behaviors (methods) from an existing class (superclass).

Question 2

How do you create a sub class?

Answer 2

Use the ‘extends’ keyword.
(class Dog extends Animal { )

Question 3

What does the super() constructor call?

Answer 3

The super() call invokes the constructor of the super class. It must be the first statement in the subclass constructor.

Question 4

What is polymorphism?

Answer 4

Polymorphism allows objects of different classes to be treated as objects of a common super class. The most common use is method overriding, where a subclass can define its own version of a method.

Question 5

What is the difference between ‘is-a’ and ‘has-a’ relationships in inheritance?

Answer 5

is-a represents inheritance. (Dog is-a Animal)

has-a represents composition. (Car has-a Engine)