Question

Java Questions

A class must implement at least one interface.

Question 1 options:

	True
	False

Question 2 (1 point)

Abstract methods can be called.

Question 2 options:

	True
	False

Question 3 (1 point)

Constructors

Question 3 options:

	Are inherited but cannot be accessed
	Are inherited and can be accessed
	Are accessible but are not inherited
	Are not inherited and cannot be accessed

Question 4 (1 point)

We can instantiate an object from an abstract class.

Question 4 options:

	True
	False

Question 5 (1 point)

When is it determined which method is called when using polymorphism?

Question 5 options:

	At compile time
	At the time of writing code
	At runtime

Question 6 (1 point)

An abstract method _________________

Question 6 options:

	Has a �do-nothing� body
	Does not have a body
	Has a body, just like another method

Question 7 (1 point)

Assuming the class B inherits from class A and method foo belongs to class A, what do we mean by overriding method foo in class B?

Question 7 options:

	We are calling method foo in class B
	We are not using method foo in class B
	We are replacing the superclass' version of the foo method with a new foo method with the same signature

Question 8 (1 point)

An interface can contain one or more static constants.

Question 8 options:

	True
	False

Question 9 (1 point)

private fields and methods are inherited.

Question 9 options:

	True
	False

Question 10 (1 point)

A constructor can be declared abstract.

Question 10 options:

	True
	False

Answer 1

Answer 1

False. Not necessarily until class needs to use functions of any interface.

Answer 2

False. Abstract methods are without any body and they are part of abstract class. We can't create object of abstract class so methods can't be called.

Answer 3

Constructors are accessible only but not inherited.

Answer 4

False. Object can not be created for an abstract class.

Answer 5

When we use polymorphism, which method to be called is determined at run time by looking at the type of object which is assigned.

Answer 6

An abstract method does not have any body only declaration.

Answer 7

We are replacing the superclass version of the foo method with a new foo method with the same signature

Answer 8

True. We can have static constants inside interface but it's a bad practice.

Answer 9

False. Private methods are fields are not inherited. Only accessible methods and fields are inherited.

Answer 10

False. To make constructor abstract, you need to implement it it some other class but overriding constructor is not allowed.