Master Object-Oriented Programming: Interactive Quizzes for Computer Science Students

Question 1

Which statement about encapsulation in OOP best describes its purpose?

Accepted Answer

To hide data and implementation details from users.

Answer

To make code more flexible and easier to change.

Answer

To prevent unauthorized access to sensitive data.

Answer

To reduce the complexity of large software systems.

Question 2

What is the purpose of a class in object-oriented programming?

Accepted Answer

To define the data structure and behaviour of objects

Answer

To define only the data structure of objects

Answer

To define only the behaviour of objects

Answer

To define the implementation details of objects

Question 3

What is the relationship between a superclass and a subclass?

Accepted Answer

A superclass is a generalisation of a subclass, and a subclass is a specialisation of a superclass

Answer

A subclass is a generalisation of a superclass, and a superclass is a specialisation of a subclass

Answer

A superclass and a subclass are unrelated concepts

Answer

A superclass is always abstract, and a subclass is always concrete

Question 4

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

Accepted Answer

To define a contract that must be implemented by all classes that implement it

Answer

To define the data structure of objects

Answer

To define the behaviour of individual objects

Answer

To define the implementation details of objects

Question 5

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

Accepted Answer

Global state

Answer

Encapsulation

Answer

Abstraction

Answer

Inheritance

Question 6

What is the difference between a method and a constructor?

Accepted Answer

A method is used to modify the state of an object, while a constructor is used to initialise the state of an object

Answer

A constructor is used to modify the state of an object, while a method is used to initialise the state of an object

Answer

A method can be called multiple times, while a constructor can only be called once

Answer

A constructor can be overloaded, while a method cannot

Question 7

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

Accepted Answer

To refer to the current object

Answer

To refer to the superclass of the current object

Answer

To refer to the subclass of the current object

Answer

To refer to the interface of the current object

Question 8

A class defines the blueprint for creating:

Accepted Answer

Objects

Answer

Variables

Answer

Functions

Answer

Modules

Question 9

Which of the following is NOT a characteristic of inheritance?

Accepted Answer

Creating multiple instances

Answer

Reusing code

Answer

Extending functionality

Answer

Overriding methods

Question 10

In Java, the primary purpose of a constructor is to:

Accepted Answer

Initialize an object

Answer

Define the behavior of an object

Answer

Inherit properties from a parent class

Answer

Handle exceptions

Question 11

Which of the following is NOT a valid scope in the Java programming language?

Accepted Answer

Global

Answer

Class

Answer

Method

Answer

Block

Question 12

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

Accepted Answer

class

Answer

int

Answer

object

Answer

public

Question 13

What is the primary purpose of inheritance in OOP?

Accepted Answer

To reuse and extend existing code

Answer

To create new objects dynamically

Answer

To enforce data security

Answer

To handle exceptions

Question 14

Explain the distinction between a class and an object in OOP.

Accepted Answer

A class is a blueprint for creating objects, whereas an object is an instance of a class

Answer

An object is a blueprint for creating classes, whereas a class is an instance of an object

Answer

There is no difference between a class and an object

Answer

A class is a data type, while an object is a variable

Question 15

Which of the following is not considered an advantage of OOP?

Accepted Answer

Increased code complexity

Answer

Increased code reusability

Answer

Improved code maintainability

Answer

Reduced run-time errors

Question 16

Which modifier can be used to prevent a method from being overridden in Java?

Accepted Answer

final

Answer

static

Answer

private

Answer

public

Question 17

What is the main purpose of encapsulation in OOP?

Accepted Answer

To protect data and methods from unauthorized access

Answer

To improve code readability

Answer

To enhance code performance

Answer

To facilitate code reuse

Question 18

Which of the following is a key characteristic of polymorphism?

Accepted Answer

The ability for objects of different classes to respond to the same method call

Answer

The ability to create objects of different classes dynamically

Answer

The ability to inherit methods from multiple parent classes

Answer

The ability to override methods in subclasses

Question 19

Which design pattern is commonly used to create objects without specifying their exact class?

Accepted Answer

Factory pattern

Answer

Builder pattern

Answer

Singleton pattern

Answer

Observer pattern

Question 20

In Java, what is the primary role of the `this` keyword?

Accepted Answer

References the current object within an instance method

Answer

Calls a constructor from another constructor within the same class

Answer

Passes an object as an argument to another method

Answer

Provides access to private members of the class

Question 21

What is the process of converting an object from one data type to another referred to as?

Accepted Answer

Casting

Answer

Cloning

Answer

Serialization

Answer

Deserialization

Question 22

Which design pattern guarantees that a class has only one instance?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Observer

Answer

Strategy

Question 23

Which of the following is a fundamental principle of object-oriented programming (OOP)?

Accepted Answer

Encapsulation

Answer

Recursion

Answer

Iteration

Answer

Concatenation

Question 24

What is the term for creating an instance of a class?

Accepted Answer

Instantiating

Answer

Initialising

Answer

Overloading

Answer

Declaring

Question 25

Which of the following is a key benefit of inheritance?

Accepted Answer

Code reuse

Answer

Reduced complexity

Answer

Improved performance

Answer

Enhanced security

Question 26

Which design pattern is used to create objects in a controlled manner, ensuring that only one instance of a class is created?

Accepted Answer

Singleton

Answer

Factory

Answer

Observer

Answer

Adapter

Question 27

What is the relationship between a class and an interface?

Accepted Answer

A class can implement multiple interfaces

Answer

An interface can extend multiple classes

Answer

A class can only inherit from one interface

Answer

An interface cannot have any abstract methods

Question 28

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

Accepted Answer

Encapsulation: Bundles data and methods into individual units called objects

Answer

Reusability: Allows code to be reused in multiple programs

Answer

Modularity: Breaks down a program into independent, interchangeable modules

Answer

Simplicity: Simplifies the design and implementation of complex systems

Question 29

What is the primary purpose of a class in OOP?

Accepted Answer

Defines the blueprint or template for creating objects

Answer

Creates specific instances of objects

Answer

Handles user input and interactions

Answer

Implements specific algorithms and functionality

Question 30

What is the term used to describe the ability of an object to exhibit different behaviors based on its class?

Accepted Answer

Polymorphism: Different behaviors based on object class

Answer

Encapsulation: Hiding implementation details

Answer

Abstraction: Hiding unnecessary details

Answer

Encapsulation: Bundling data and methods

Question 31

What is the fundamental difference between a constructor and a method in a class?

Accepted Answer

A constructor initializes an object's state upon creation, while a method defines its behavior

Answer

A method initializes an object's state upon creation, while a constructor defines its behavior

Answer

Constructors and methods are essentially the same thing

Answer

There is no difference between a constructor and a method

Question 32

What is the primary purpose of an abstract class in OOP?

Accepted Answer

To define a set of abstract methods that must be implemented in derived classes

Answer

To create objects that can be instantiated

Answer

To implement specific functionality that can be reused

Answer

To prevent inheritance

Question 33

What is the term used to describe the process of hiding the implementation details of an object from other parts of the program?

Accepted Answer

Encapsulation: Concealing implementation details

Answer

Abstraction: Simplifying complex concepts

Answer

Inheritance: Deriving new classes from existing ones

Answer

Polymorphism: Exhibiting different behaviors

Question 34

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

Accepted Answer

Sequential execution

Answer

Encapsulation

Answer

Abstraction

Answer

Polymorphism

Question 35

In object-oriented programming, what is the relationship between a superclass and a subclass?

Accepted Answer

The subclass inherits from the superclass

Answer

The superclass inherits from the subclass

Answer

The superclass and subclass are unrelated

Answer

The subclass overrides the superclass

Question 36

What is the best definition of polymorphism?

Accepted Answer

Objects of different classes can respond to the same message

Answer

Objects of the same class can respond to different messages

Answer

Objects can change their class at runtime

Answer

Objects can inherit from multiple classes

Question 37

Which modifier is used to restrict access to a class only within its package?

Accepted Answer

default

Answer

public

Answer

protected

Answer

private

Question 38

What is the primary purpose of the 'this' keyword?

Accepted Answer

To access the current object

Answer

To call a superclass constructor

Answer

To pass an object as an argument

Answer

To declare a local variable

Question 39

What is the proper syntax for declaring an array in Java?

Accepted Answer

int[] arr;

Answer

int arr[];

Answer

int[ ] arr;

Answer

arr int[];

Question 40

Which of the following is not a valid looping statement in Java?

Accepted Answer

if

Answer

for

Answer

while

Answer

do-while

Question 41

Which of the following is **not** a fundamental principle of object-oriented programming?

Accepted Answer

Aggregation

Answer

Encapsulation

Answer

Inheritance

Answer

Polymorphism

Question 42

The process of creating a new object from an existing class is known as:

Accepted Answer

Instantiation

Answer

Inheritance

Answer

Abstraction

Answer

Encapsulation

Question 43

Which keyword is used to specify the superclass of a class in Java?

Accepted Answer

extends

Answer

implements

Answer

overrides

Answer

super

Question 44

What is the purpose of polymorphism in object-oriented programming?

Accepted Answer

To allow objects of different classes to be treated as objects of a common superclass

Answer

To prevent objects of different classes from being treated as objects of a common superclass

Answer

To increase the speed of program execution

Answer

To reduce the memory consumption of a program

Question 45

What is the difference between an abstract class and an interface in Java?

Accepted Answer

An interface can have abstract methods, while an abstract class can have both abstract and non-abstract methods

Answer

An abstract class can have abstract methods, while an interface can only have abstract methods

Answer

An abstract class can have constructors, while an interface cannot

Answer

An interface can have constructors, while an abstract class cannot

Question 46

Which of the following is the correct syntax to create an object in Java?

Accepted Answer

object_name = new ClassName()

Answer

ClassName object_name = new()

Answer

new object_name = ClassName()

Answer

new ClassName() = object_name

Question 47

What is the purpose of using access modifiers in object-oriented programming?

Accepted Answer

To control the visibility of classes, methods, and variables

Answer

To increase the speed of program execution

Answer

To reduce the memory consumption of a program

Answer

To improve code readability

Question 48

Which of the following best describes inheritance in object-oriented programming?

Accepted Answer

A subclass inherits properties and methods from a superclass

Answer

A class uses a library to access external functions

Answer

A method calls another method within the same class

Answer

A class implements an interface

Question 49

What is the key difference between method overloading and method overriding?

Accepted Answer

Overloading involves changing the method signature, while overriding involves changing the method implementation.

Answer

Overriding involves changing the method signature, while overloading involves changing the method implementation.

Answer

Both involve changing the method signature.

Answer

Both involve changing the method implementation.