1Z0-811 Inheritance and Polymorphism

Question 1

Which keyword is used in Java to create a subclass that inherits from a parent class?

Accepted Answer

extends

Answer

implements

Answer

inherits

Answer

super

Question 2

How many classes can a Java class directly extend?

Accepted Answer

Only one

Answer

Up to two

Answer

Up to three

Answer

Unlimited

Question 3

What does calling 'super()' inside a constructor do?

Accepted Answer

Calls the parent class constructor

Answer

Creates a new instance of the parent class

Answer

References the current class instance

Answer

Invokes a static method from the parent

Question 4

Which access modifier makes a member accessible to subclasses in different packages but not to unrelated classes?

Accepted Answer

protected

Answer

private

Answer

public

Answer

default

Question 5

Are constructors inherited by subclasses in Java?

Accepted Answer

No, constructors are not inherited

Answer

Yes, all constructors are inherited

Answer

Yes, but only public constructors are inherited

Answer

Yes, but only if the superclass has a no-arg constructor

Question 6

What is the implicit parent class of every Java class that does not explicitly extend another class?

Accepted Answer

java.lang.Object

Answer

java.lang.Base

Answer

java.lang.Class

Answer

java.lang.Root

Question 7

Given: class Animal {} and class Dog extends Animal {}, which statement is true?

Accepted Answer

Dog is a type of Animal

Answer

Animal is a subtype of Dog

Answer

Dog cannot access Animal's public methods

Answer

Animal implicitly extends Dog