Design Patterns: Master Object-Oriented Programming with Confidence

Question 1

In object-oriented programming, which design pattern is primarily used to provide a consistent interface for creating objects of various types while decoupling client code from implementation details?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Builder

Answer

Command

Question 2

A key advantage of utilizing the Singleton design pattern is:

Accepted Answer

Ensuring only one instance of a class exists throughout the application.

Answer

Simplifying object creation by eliminating the need for complex instantiation processes.

Answer

Enhancing application performance by optimizing memory usage and reducing object overhead.

Answer

Encouraging loose coupling between objects and promoting code maintainability.

Question 3

Which of the following options does NOT represent a design pattern classified as creational?

Accepted Answer

Command

Answer

Abstract Factory

Answer

Builder

Answer

Factory Method

Question 4

Within the Factory Method design pattern, the ConcreteFactory class is responsible for:

Accepted Answer

Creating specific instances of the Product class based on client requests.

Answer

Defining a common interface for creating objects.

Answer

Managing the overall creation process and providing an abstraction for object instantiation.

Answer

Encapsulating the logic for determining which type of Product to create.

Question 5

The primary purpose of the Adapter design pattern is to:

Accepted Answer

Translate the interface of one class into another, enabling incompatible classes to work together.

Answer

Provide a uniform interface for a group of unrelated classes, simplifying client interactions.

Answer

Create a new class that inherits from multiple parent classes, combining their functionalities.

Answer

Implement multiple interfaces in a single class, allowing it to exhibit various behaviors.

Question 6

Which design pattern category does NOT include the Adapter pattern?

Accepted Answer

Concurrency

Answer

Creational

Answer

Structural

Answer

Behavioral

Question 7

What is a key benefit of using design patterns in software development?

Accepted Answer

Improved code readability and ease of maintenance

Answer

Reduced development time

Answer

Complete elimination of software defects

Question 8

In object-oriented programming, which design pattern allows subclasses to modify the type of objects created?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Decorator

Answer

Adapter

Question 9

Which design pattern defines an interface for creating a family of related objects without specifying their concrete classes?

Accepted Answer

Abstract Factory

Answer

Factory Method

Answer

Builder

Answer

Prototype

Question 10

Which design pattern provides an object that acts as a substitute for another object to control access to it?

Accepted Answer

Proxy

Answer

Adapter

Answer

Decorator

Answer

Facade

Question 11

Which design pattern allows you to define a family of algorithms, encapsulate each one, and make them interchangeable?

Accepted Answer

Strategy

Answer

Template Method

Answer

Visitor

Answer

Observer

Question 12

Which design pattern enables objects to subscribe to events published by other objects?

Accepted Answer

Observer

Answer

Strategy

Answer

Template Method

Answer

Composite

Question 13

Which creational design pattern offers a standard interface for object creation, separating the creation logic from the client code?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Strategy

Answer

Decorator

Question 14

Which of the following is **NOT** a benefit of using design patterns?

Accepted Answer

Enhanced code complexity

Answer

Increased code reusability

Answer

Improved software maintainability

Answer

Reduced testing effort

Question 15

Which design pattern ensures that only a single instance of a class can be created?

Accepted Answer

Singleton

Answer

Composite

Answer

Facade

Answer

State

Question 16

Which design pattern allows objects to subscribe to and receive notifications from other objects?

Accepted Answer

Observer

Answer

Prototype

Answer

Iterator

Answer

Mediator

Question 17

Which of the following is a key concept of the iterator pattern?

Accepted Answer

Accessing elements sequentially

Answer

Retrieving objects dynamically

Answer

Creating copies of objects

Answer

Storing objects in a collection

Question 18

Which of the following is NOT a benefit of using design patterns?

Accepted Answer

Elimination of all software errors

Answer

Increased code reusability

Answer

Improved software maintainability

Answer

Reduced development time

Question 19

Which design pattern is best suited for ensuring that a class has only one instance?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Adapter

Answer

Observer

Question 20

In a composite pattern, which class represents a collection of objects?

Accepted Answer

Composite

Answer

Component

Answer

Leaf

Answer

Decorator

Question 21

What is the key difference between the strategy and state patterns?

Accepted Answer

Strategy pattern encapsulates algorithms, while state pattern encapsulates object behaviour

Answer

State pattern encapsulates algorithms, while strategy pattern encapsulates object behaviour

Answer

Strategy pattern is implemented using inheritance, while state pattern is implemented using composition

Answer

State pattern is implemented using inheritance, while strategy pattern is implemented using composition

Question 22

Which design pattern is used to provide a simplified interface to a complex system?

Accepted Answer

Facade

Answer

Mediator

Answer

Observer

Answer

Composite

Question 23

Which design pattern ensures that only a single instance of a class exists and provides global access to that instance?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Prototype

Answer

Builder

Question 24

What principle of object-oriented design advocates that each object should be responsible for a well-defined set of tasks, enhancing its cohesion and reducing coupling?

Accepted Answer

Single Responsibility Principle

Answer

Open-Closed Principle

Answer

Interface Segregation Principle

Answer

Liskov Substitution Principle

Question 25

Which of the following is NOT considered an advantage of utilizing design patterns in software development?

Accepted Answer

Increased code execution time

Answer

Enhanced code flexibility

Answer

Reusable solutions

Answer

Improved code readability

Question 26

What is the primary purpose of the Builder pattern?

Accepted Answer

To separate the construction of a complex object from its representation, allowing for the creation of different variations of the object.

Answer

To create objects without specifying the exact class of the object.

Answer

To provide a mechanism for undoing operations.

Question 27

Which of the following is a distinguishing characteristic of the Command pattern?

Accepted Answer

Encapsulates a request as an object, allowing for its parameterization, queuing, and logging.

Answer

Defines an object that represents a group of objects.

Answer

Provides a consistent interface to different classes.

Answer

Creates a factory for creating different products.

Question 28

What is the central goal of the Observer pattern?

Accepted Answer

To define a one-to-many dependency between objects, where changes to the state of one object (the subject) automatically notify and update all its dependent objects (the observers).

Answer

To create objects without specifying the exact class of the object.

Question 29

Which design pattern is particularly well-suited for representing hierarchical structures of objects?

Accepted Answer

Composite

Answer

Decorator

Answer

Bridge

Answer

Adapter

Question 30

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

Accepted Answer

Factory method

Answer

Builder

Answer

Prototype

Question 31

Which design pattern ensures that only a single instance of a class is created and provides global access to it?

Accepted Answer

Singleton

Answer

Prototype

Answer

Builder

Answer

Factory method

Question 32

Which design pattern allows for dynamically adding or removing responsibilities from an object?

Accepted Answer

Decorator

Answer

Adapter

Answer

Proxy

Answer

Observer

Question 33

Which design pattern encapsulates a family of algorithms and allows interchangeable selection and execution of each?

Accepted Answer

Strategy

Answer

Command

Answer

Observer

Question 34

Which design pattern allows for observing the state of an object and notifying observers about changes?

Accepted Answer

Observer

Answer

Command

Answer

Mediator

Question 35

Which design pattern converts the interface of a class into a compatible one by wrapping it in an adapter object?

Accepted Answer

Adapter

Answer

Decorator

Answer

Bridge

Answer

Proxy

Question 36

Which design pattern encapsulates a request as an object, allowing it to be parameterized, queued, and executed later?

Accepted Answer

Command

Answer

Observer

Answer

Strategy

Answer

Template method

Question 37

Which design pattern stores the internal state of an object so that it can be restored later?

Accepted Answer

Memento

Answer

Observer

Answer

Proxy

Answer

Decorator

Question 38

Which design pattern defines the skeleton of an algorithm and allows subclasses to override specific steps while preserving the overall structure?

Accepted Answer

Template method

Answer

Observer

Answer

Strategy

Answer

Decorator

Question 39

Which design pattern provides an interface for creating objects but allows subclasses to alter the type of objects that will be created?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Abstract Factory

Answer

Builder

Question 40

Which design pattern ensures that a class has only one instance and provides a global point of access to that instance?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Decorator

Question 41

Which design pattern provides a way to add new functionality to an existing object without modifying its structure?

Accepted Answer

Decorator

Answer

Adapter

Answer

Proxy

Answer

Builder

Question 42

Which design pattern allows a group of objects to be treated as a single object?

Accepted Answer

Composite

Answer

Decorator

Answer

Proxy

Answer

Facade

Question 43

Which design pattern defines a family of algorithms, encapsulates each one and makes them interchangeable, while keeping the algorithms independent of client code?

Accepted Answer

Strategy

Answer

Mediator

Answer

Command

Answer

Interpreter

Question 44

Which design pattern allows an object to delegate part of its functionality to another object?

Accepted Answer

Command

Answer

Observer

Answer

Facade

Answer

Strategy

Question 45

Which design pattern provides a way to communicate between objects without specifying the classes of the objects or their implementation?

Accepted Answer

Mediator

Answer

Observer

Answer

Command

Answer

Interpreter

Question 46

Which design pattern allows objects to subscribe to and receive notifications from other objects?

Accepted Answer

Observer

Answer

Command

Answer

Proxy

Answer

Decorator