Object-Oriented Programming Quizzes: Test Your Skills

Question 1

Polymorphism allows classes and objects to share a common interface but have different implementations. Which of the following is NOT a type of polymorphism?

Accepted Answer

Coercion

Answer

Overloading

Answer

Overriding

Answer

Method overriding

Question 2

In object-oriented programming, which design pattern is used to create a hierarchy of classes that share a common interface?

Accepted Answer

Inheritance

Answer

Singleton

Answer

Factory Method

Answer

Adapter

Question 3

What is the defining characteristic that distinguishes object-oriented programming (OOP) from other programming approaches?

Accepted Answer

OOP focuses on manipulating data through objects, while other paradigms prioritize procedural steps.

Answer

OOP is specifically designed for large-scale software projects, while other paradigms are more suitable for smaller ones.

Answer

OOP exclusively uses static typing, while other paradigms allow for both static and dynamic typing.

Question 4

Which principle states that classes should be open for extension but closed for modification?

Accepted Answer

Open/Closed Principle

Answer

Liskov Substitution Principle

Answer

Single Responsibility Principle

Answer

Interface Segregation Principle

Question 5

Explain the advantages of inheritance in object-oriented programming. Provide an example of how inheritance can be used to create a class hierarchy in a real-world application.

Accepted Answer

Inheritance enables code reuse, simplifies complexity, and enhances flexibility by allowing new classes to inherit attributes and behaviors from existing classes.

Answer

Inheritance is solely used to create new classes from existing ones but offers no benefits in OOP.

Answer

Inheritance is primarily used to create new objects from existing ones.

Question 6

Within object-oriented programming, which testing approach is used to evaluate individual code units, like functions or methods?

Accepted Answer

Unit Testing

Answer

Black-Box Testing

Answer

Integration Testing

Answer

Acceptance Testing

Question 7

In Agile software development, how can the principles of object-oriented programming (OOP) be effectively applied?

Accepted Answer

Encapsulate data and functionality into reusable and maintainable components.

Answer

Enforce rigid class structures through inheritance hierarchies.

Answer

Prioritize code optimization over design principles.

Answer

OOP cannot be effectively integrated with Agile methodologies.

Question 8

In object-oriented programming, which debugging technique involves adding print statements to the code to display variable values and track the execution flow, helping to locate the cause of errors?

Accepted Answer

Print debugging

Answer

Inserting breakpoints in the code

Answer

Utilizing a debugging tool

Question 9

In business modeling, how can object-oriented programming principles be best utilized?

Accepted Answer

By organizing data and actions into reusable and manageable units.

Answer

By enforcing strict data types and variable declarations for data reliability.

Answer

By enabling real-time updates for multiple users through a shared database.

Answer

By designing graphical user interfaces with interactive buttons and menus.

Question 10

When developing systems that handle sensitive data using OOP, what ethical considerations should developers prioritize?

Accepted Answer

Ensuring data security and authorized access

Answer

Prioritizing efficiency over security

Answer

Ignoring ethical obligations beyond functional requirements

Answer

Disregarding ethical considerations if the software functions correctly

Question 11

In object-oriented programming, what is refactoring and how does it enhance code quality and maintainability?

Accepted Answer

Refactoring involves modifying code to improve its clarity, reduce complexity, and optimize its structure, without changing its functionality.

Answer

Refactoring adds new features to an existing codebase to enhance code quality.

Answer

Refactoring simplifies code quality by removing unnecessary code.

Answer

Refactoring alters code behavior to fix bugs or add features, thereby improving code quality.

Question 12

Describe the purpose of an 'interface' in object-oriented programming:

Accepted Answer

Defines a set of methods that classes must implement

Answer

Creates a new class

Answer

Inherits from a superclass

Answer

Stores data

Question 13

Which of the following is a valid variable name in Java syntax?

Accepted Answer

age

Answer

_age

Answer

1age

Answer

ag&e

Question 14

Differentiate between a 'class' and an 'object' in object-oriented programming:

Accepted Answer

A class is a blueprint, while an object is an instance of that blueprint

Answer

An object is a blueprint, while a class is an instance of that blueprint

Answer

They are synonymous

Answer

There is no distinction

Question 15

State the role of a 'constructor' in Java:

Accepted Answer

Initializes an object's state

Answer

Creates a new object

Answer

Defines an object's behavior

Answer

Destroys an object

Question 16

Which of the following is not a visibility modifier in Java?

Accepted Answer

internal

Answer

public

Answer

private

Answer

protected

Question 17

Explain the difference between 'this' and 'super' keywords in Java:

Accepted Answer

'this' refers to the current object, while 'super' refers to the superclass

Answer

'super' refers to the current object, while 'this' refers to the superclass

Answer

They have the same function

Answer

There is no distinction

Question 18

What is the primary purpose of using 'packages' in Java?

Accepted Answer

Organize related classes and interfaces

Answer

Generate namespaces

Answer

Control visibility of classes and interfaces

Answer

Store data

Question 19

Which of the following is NOT a characteristic of object-oriented programming?

Accepted Answer

Imperative programming

Answer

Encapsulation (data hiding)

Answer

Inheritance

Answer

Polymorphism

Question 20

In JavaScript, which keyword is used to define a class?

Accepted Answer

class

Answer

object

Answer

function

Answer

define

Question 21

What is polymorphism in object-oriented programming?

Accepted Answer

Ability of objects to behave differently based on their type

Answer

Creation of objects with different properties and methods

Answer

Inheritance of properties and methods from parent classes

Answer

Encapsulation of data and methods within objects

Question 22

What is the primary purpose of encapsulation in OOP?

Accepted Answer

To hide implementation details (data hiding)

Answer

To improve code efficiency

Answer

To enforce data integrity

Answer

To facilitate collaboration

Question 23

What is the relationship between a class and an object?

Accepted Answer

Class is a blueprint; object is an instance

Answer

Object is a blueprint; class is an instance

Answer

Class and object are the same thing

Answer

Class is a property; object is a method

Question 24

What is the purpose of an interface in object-oriented programming?

Accepted Answer

To define a contract that classes must implement

Answer

To create a new class

Answer

To inherit properties and methods from another class

Answer

To encapsulate data and methods

Question 25

What is the primary purpose of a class in OOP?

Accepted Answer

To define a blueprint or template for creating individual objects.

Answer

To store data about objects, such as their properties and values.

Answer

To perform operations on objects, such as methods and functions.

Answer

To create new objects dynamically during program execution.

Question 26

Which of the following scenarios best exemplifies inheritance in OOP?

Accepted Answer

Creating a subclass called 'Student' that inherits the properties and methods of a superclass called 'Person'.

Answer

Creating an object called 'car' that inherits the properties of another object called 'vehicle'.

Answer

Creating a class called 'Animal' that implements a specific interface called 'Edible'.

Answer

Creating a method called 'calculateArea()' that overrides a method with the same name in a superclass.

Question 27

What is the primary role of an interface in OOP?

Accepted Answer

To define a contract that specifies the methods that any class implementing the interface must provide.

Answer

To define a set of properties that any class implementing the interface must have.

Answer

To define a set of events that any class implementing the interface can trigger.

Answer

To define a set of constants that any class implementing the interface can access.

Question 28

What is the fundamental difference between an abstract class and a concrete class in OOP?

Accepted Answer

An abstract class cannot be instantiated directly, while a concrete class can.

Answer

A concrete class cannot be instantiated directly, while an abstract class can.

Answer

An abstract class contains only abstract methods, while a concrete class contains only concrete methods.

Answer

A concrete class contains only abstract methods, while an abstract class contains only concrete methods.

Question 29

Which of the following is a defining characteristic of object-oriented programming (OOP)?

Accepted Answer

Encapsulation of data and methods within objects

Answer

Sequential execution of statements

Answer

Use of global variables for data storage

Answer

Top-down design approach

Question 30

What is the primary purpose of inheritance in OOP?

Accepted Answer

To reuse code and avoid redundancy

Answer

To create new classes with extended capabilities

Answer

To establish associations between objects

Answer

To enforce access control to data

Question 31

What is the distinction between a class and an object in OOP?

Accepted Answer

A class is a template or blueprint, while an object is an instance of that class

Answer

An object is a template or blueprint, while a class is an instance of that object

Answer

Classes and objects are interchangeable terms

Answer

Only objects have access to methods

Question 32

Which of the following access modifiers is used to restrict access to class members in Java?

Accepted Answer

private

Answer

protected

Answer

internal

Answer

public

Question 33

What is the primary function of an interface in OOP?

Accepted Answer

To define a contract that classes must adhere to

Answer

To group similar classes together

Answer

To create multiple instances of an object

Answer

To improve code readability

Question 34

What is the fundamental difference between static and non-static methods in OOP?

Accepted Answer

Static methods operate on the class itself, while non-static methods operate on objects

Answer

Non-static methods operate on the class itself, while static methods operate on objects

Answer

Static methods can be inherited, while non-static methods cannot

Answer

Non-static methods can only access instance variables, while static methods can access both instance and static variables

Question 35

What is the primary purpose of a Unified Modeling Language (UML) class diagram?

Accepted Answer

To visually represent the structure and relationships of classes in a system

Answer

To automatically generate code

Answer

To document design decisions

Answer

To test software functionality

Question 36

Which of the following is NOT an object-oriented programming language?

Accepted Answer

C

Answer

Python

Answer

Java

Answer

C#

Question 37

An interface in object-oriented programming is used to:

Accepted Answer

Define a contract that classes must implement

Answer

Provide a means of communication between objects

Answer

Enhance the performance of a program

Answer

Protect sensitive data

Question 38

A well-designed object-oriented program should exhibit:

Accepted Answer

High cohesion and low coupling

Answer

Low cohesion and high coupling

Answer

High cohesion and high coupling

Answer

Low cohesion and low coupling

Question 39

Which characteristic is NOT associated with object-oriented programming?

Accepted Answer

Procedural abstraction

Answer

Encapsulation

Answer

Inheritance

Answer

Modularity

Question 40

What is the process in object-oriented programming where new classes are created from existing ones?

Accepted Answer

Inheritance

Answer

Polymorphism

Answer

Encapsulation

Answer

Generalization

Question 41

What is the primary purpose of encapsulation in object-oriented programming?

Accepted Answer

Restricting access to an object's internal data

Answer

Facilitating interaction between objects

Answer

Defining object behavior

Answer

Enhancing object independence

Question 42

Which object-oriented programming language is renowned for its rigorous type system?

Accepted Answer

Java

Answer

Python

Answer

JavaScript

Answer

PHP

Question 43

What is the primary function of a constructor in object-oriented programming?

Accepted Answer

Initializing an object's state

Answer

Defining object behavior

Answer

Creating a new class

Answer

Destroying an object

Question 44

Which access modifier is used to restrict access to an object's members?

Accepted Answer

Private

Answer

Public

Answer

Protected

Answer

Internal

Question 45

What is the concept of method overloading in object-oriented programming?

Accepted Answer

Having multiple methods with the same name but different parameters

Answer

Having multiple methods with the same parameters but different return types

Answer

Having multiple classes with the same name

Answer

Having multiple objects with the same reference

Question 46

What is the purpose of the 'this' keyword in object-oriented programming?

Accepted Answer

Referencing the current object

Answer

Referencing the parent class

Answer

Referencing the child class

Answer

Creating a new object

Question 47

What is the process of creating a new object from a class called in object-oriented programming?

Accepted Answer

Instantiating

Answer

Initialising

Answer

Creating

Answer

Generating

Question 48

Which of the following is **NOT** an advantage of inheritance in object-oriented programming?

Accepted Answer

Improved code readability

Answer

Reduced code duplication

Answer

Enhanced maintainability

Answer

Increased flexibility

Question 49

What type of relationship exists between a subclass and its superclass in object-oriented programming?

Accepted Answer

The subclass inherits all the data members and methods of the superclass.

Answer

The subclass can only access the public data members and methods of the superclass.

Answer

The subclass can modify the data members and methods of the superclass.

Answer

The subclass has no relationship with the superclass.

Question 50

Which of the following is **NOT** a form of polymorphism in object-oriented programming?

Accepted Answer

Constructor overloading

Answer

Method overloading

Answer

Method overriding

Answer

Operator overloading

Question 51

What is the purpose of an interface in object-oriented programming?

Accepted Answer

To define a contract that classes must implement.

Answer

To provide a way for classes to communicate with each other.

Answer

To increase the reusability of code.

Answer

To improve the performance of a program.

Question 52

Which of the following is **NOT** a benefit of using object-oriented programming?

Accepted Answer

Faster program execution

Answer

Improved code organisation

Answer

Increased code reusability

Answer

Enhanced maintainability

Question 53

Which of the following is **not** a primitive data type in Java?

Accepted Answer

String

Answer

int

Answer

float

Answer

boolean

Question 54

What primary purpose does a constructor serve in object-oriented programming languages?

Accepted Answer

To initialize the internal state of an object

Answer

To terminate the existence of an object

Answer

To define the behavior of an object

Answer

To facilitate communication among objects

Question 55

Define encapsulation in the context of OOP.

Accepted Answer

Concealing the internal state of an object from external access

Answer

Combining data and methods into a cohesive unit

Answer

Separating the interface of a class from its implementation

Answer

Providing multiple access points to the same data

Question 56

What is the difference between a class and an object?

Accepted Answer

A class is a blueprint for creating objects, while an object is an instantiation of a class

Answer

An object is a blueprint for creating classes, while a class is an instantiation of an object

Answer

Classes and objects are interchangeable concepts

Answer

Neither classes nor objects are used in OOP

Question 57

Provide an example of method overriding.

Accepted Answer

When a subclass defines a method with the same name and signature as a method in its superclass

Answer

When a subclass defines a method with a different name and signature than a method in its superclass

Answer

When a superclass defines a method with the same name and signature as a method in its subclass

Answer

Method overriding is not a concept in OOP

Question 58

What is the primary purpose of interfaces in object-oriented programming?

Accepted Answer

To establish a contract that classes must adhere to

Answer

To provide a mechanism for objects to communicate with one another

Answer

To dynamically generate new classes

Answer

Interfaces are not utilized in OOP

Question 59

Which of the following is NOT a primitive data type in Java?

Accepted Answer

Text (string)

Answer

Integer (int)

Answer

Decimal (float)

Answer

True/False (boolean)

Question 60

What is the primary purpose of a constructor in Java?

Accepted Answer

To initialize an object's attributes

Answer

To assign values to object attributes

Answer

To return a new object

Answer

To create a new object

Question 61

What is the process of creating a new object based on an existing class called?

Accepted Answer

Instantiation

Answer

Inheritance

Answer

Polymorphism

Answer

Abstraction

Question 62

Which access specifier restricts access to a class's members to within the class itself?

Accepted Answer

Private

Answer

Protected

Answer

Public

Answer

Internal

Question 63

What is the term for modifying a method in a subclass that is inherited from a superclass?

Accepted Answer

Overriding

Answer

Overloading

Answer

Extending

Answer

Polymorphism

Question 64

Which of the following is an example of polymorphic behaviour?

Accepted Answer

A dog and a cat making different sounds

Answer

A car and a plane using different fuels

Answer

A circle and a square having different shapes

Answer

A student and a teacher having different roles