40 interview questions on Object-oriented programming - Fundamentals for developers (2024)

Hard

8 votes550 runs0 comment

Overrided method visibility must be the same or less restrictive than the inherited method.

IT Architect

OOP

visibility

inheritance

Samuelat Mar 28, 2022

Easy

7 votes570 runs0 comment

Inheritance in OOP.

IT Architect

OOP

inheritance

methods

Samuelat Mar 28, 2022

Easy

4 votes561 runs0 comment

Can a class implements several interfaces ?

IT Architect

OOP

interfaces

inheritance

Samuelat Mar 28, 2022

Medium

4 votes536 runs1 comment

When can you do a+b in OOP ?

IT Architect

OOP

operator overloading

classes

Samuelat Mar 28, 2022

Medium

2 votes486 runs0 comment

Explain the difference between overriding and overloading in OOP.

IT Architect

OOP

methods

inheritance

Samuelat Mar 28, 2022

Medium

1 vote520 runs2 comments

In this code, the class B extends the class A. The class B overrides the method talk() from the class A. The object b is an instance of the class B. The object a is an instance of the class A. The object a is assigned to the object b. The object a calls the method talk(). The method talk() from the class B is called.

IT Architect

OOP

inheritance

polymorphism

Samuelat Mar 28, 2023

Expert

1 vote481 runs1 comment

What does the following code return ? public class A { public void talk() { echo "I am A" } public secretTalk() { this.talk() } } public class B extends A { private void talk() { echo "I am B" } public secretTalk() { this.talk() } } A b = new B() b.talk() b.secretTalk() Answer : "I am A" "I am B"

IT Architect

OOP

inheritance

overriding

Samuelat Mar 28, 2022

Easy

1 vote451 runs0 comment

How to apply the principle of encapsulation in OOP?

IT Architect

OOP

encapsulation

visibility

Samuelat Mar 28, 2022

Medium

1 vote450 runs0 comment

Overloading an operator in OOP

IT Architect

OOP

operators

classes

Samuelat Mar 28, 2022

Medium

1 vote137 runs0 comment

How to add two vectors in a class Vector2D in OOP

IT Architect

OOP

operator overloading

classes

Samuelat Mar 28, 2022

Hard

0 vote498 runs2 comments

Which modification of the following code WILL NOT make the output be "success" ?

IT Architect

OOP

inheritance

overriding

Samuelat Mar 28, 2022

Medium

0 vote486 runs0 comment

How to instantiate objects with a type which is derivated from an abstract type in OOP

IT Architect

OOP

design pattern

abstract

Samuelat Mar 28, 2022

Medium

0 vote459 runs1 comment

What does the following code return ?

IT Architect

OOP

inheritance

access modifiers

Samuelat Mar 28, 2022

Easy

0 vote457 runs0 comment

Encapsulation rule in Object-Oriented Programming

IT Architect

OOP

encapsulation

classes

Samuelat Mar 28, 2022

Hard

0 vote457 runs1 comment

Can the dynamic type of an object change after its instantiation?

IT Architect

OOP

object

type

Samuelat Mar 28, 2022

Easy

0 vote454 runs0 comment

Which Design Pattern should I use if I want an object to be notified when another kind of object state changed?

IT Architect

OOP

design pattern

observer

Samuelat Mar 28, 2022

Medium

0 vote451 runs0 comment

What does this code return ? public class A { public void talk() { echo "Hello my name is A" } } public class B extends A { public void talk() { echo "Hello my name is B" } } B b = new B(); A a = b; B b2 = (B) a; b2.talk();

IT Architect

OOP

inheritance

polymorphism

Samuelat Mar 28, 2022

Medium

0 vote451 runs1 comment

How is inheritance represented in UML?

IT Architect

OOP

uml

inheritance

Samuelat Mar 28, 2022

Easy

0 vote447 runs0 comment

What does this program print ?

IT Architect

OOP

inheritance

overriding

Samuelat Mar 28, 2022

Medium

0 vote305 runs0 comment

A child class B of an abstract class A must define the abstract methods of A.

IT Architect

OOP

abstract

class

Samuelat Mar 28, 2022

40 interview questions on Object-oriented programming - Fundamentalsfor developers (2024)

Test your technical skills before an interview of Object-oriented programming - Fundamentals with 40 corrected questions. Beginner, Intermediate or Expert level.

Overrided method visibility must be the same or less restrictive than the inherited method.

Inheritance in OOP.

Can a class implements several interfaces ?

When can you do a+b in OOP ?

Explain the difference between overriding and overloading in OOP.

What does the following code return ? public class A { public void talk() { echo "I am A" } public secretTalk() { this.talk() } } public class B extends A { private void talk() { echo "I am B" } public secretTalk() { this.talk() } } A b = new B() b.talk() b.secretTalk() Answer : "I am A" "I am B"

How to apply the principle of encapsulation in OOP?

Overloading an operator in OOP

How to add two vectors in a class Vector2D in OOP

Which modification of the following code WILL NOT make the output be "success" ?

How to instantiate objects with a type which is derivated from an abstract type in OOP

What does the following code return ?

Encapsulation rule in Object-Oriented Programming

Can the dynamic type of an object change after its instantiation?

Which Design Pattern should I use if I want an object to be notified when another kind of object state changed?

What does this code return ? public class A { public void talk() { echo "Hello my name is A" } } public class B extends A { public void talk() { echo "Hello my name is B" } } B b = new B(); A a = b; B b2 = (B) a; b2.talk();

How is inheritance represented in UML?

What does this program print ?

A child class B of an abstract class A must define the abstract methods of A.