Master Object-Oriented Design Patterns for Software Development

Question 1

Which of the following design patterns is categorized as behavioral, rather than creational?

Accepted Answer

Strategy

Answer

Factory Method

Answer

Singleton

Answer

Builder

Question 2

Design patterns are widely used in software development. Which of these is NOT a benefit of using them?

Accepted Answer

Increased code complexity

Answer

Improved code readability

Answer

Enhanced code maintainability

Question 3

Which design pattern ensures that there is only one instance of a class in the system, making it a single point of access for that class?

Accepted Answer

Singleton

Answer

Abstract Factory

Answer

Prototype

Answer

Facade

Question 4

Which design pattern allows objects to subscribe to events and get notified whenever the state of an object changes, providing a way to loosely couple objects and respond to changes dynamically?

Accepted Answer

Observer

Answer

Builder

Answer

Factory Method

Answer

Template Method

Question 5

Which design pattern promotes loose coupling between objects by wrapping a complex subsystem with a simpler interface, providing a unified way to interact with the underlying system?

Accepted Answer

Facade

Answer

Adapter

Answer

Bridge

Answer

Decorator

Question 6

Which design pattern allows multiple objects to be composed into tree structures, supporting part-whole hierarchies and enabling complex objects to be built from simpler ones?

Accepted Answer

Composite

Answer

Interpreter

Answer

Chain of Responsibility

Answer

Decorator

Question 7

Which design pattern is used to mediate communication between multiple objects, reducing coupling and simplifying interactions by providing a centralized point of control for managing communication?

Accepted Answer

Mediator

Answer

Observer

Answer

Facade

Answer

Chain of Responsibility

Question 8

Which design pattern is ideal for creating objects without explicitly specifying their exact class?

Accepted Answer

Factory Method

Answer

Builder

Answer

Singleton

Answer

Decorator

Question 9

Which design pattern enables the creation of objects without specifying the exact class of the object to be created?

Accepted Answer

Factory Method Pattern

Answer

Singleton Pattern

Answer

Builder Pattern

Question 10

Which creational design pattern allows for the creation of objects through an interface, while enabling subclasses to modify the type of objects created?

Accepted Answer

Factory Method Pattern

Answer

Singleton Pattern

Answer

Builder Pattern

Question 11

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

Accepted Answer

Singleton

Answer

Adapter

Answer

Factory Method

Answer

Builder

Question 12

Which design pattern helps maintain loose coupling between different parts of a software system by introducing a mediator that controls the interactions?

Accepted Answer

Mediator

Answer

Observer

Answer

Builder

Answer

Command

Question 13

Which design pattern allows multiple classes to register as observers and automatically receive updates when a subject's state changes?

Accepted Answer

Observer

Answer

Singleton

Answer

Factory Method

Answer

Decorator

Question 14

Which design pattern provides a way to create composite objects by assembling simpler objects into tree structures?

Accepted Answer

Composite

Answer

Strategy

Answer

Bridge

Answer

Factory Method

Question 15

Which design pattern defines a standard interface for a family of related operations and allows subclasses to redefine specific operations while maintaining the overall algorithm?

Accepted Answer

Template Method

Answer

Command

Answer

Decorator

Answer

Observer

Question 16

Which design pattern enables dynamic modification of an object's behavior by enclosing it with decorators?

Accepted Answer

Decorator

Answer

Strategy

Answer

Builder

Answer

Chain of Responsibility

Question 17

Which Design Pattern is designed to conserve memory by reusing existing objects instead of creating new ones?

Accepted Answer

Flyweight

Answer

Factory Method

Answer

Singleton

Question 18

What key benefit does the Singleton pattern offer?

Accepted Answer

Ensuring a single instance

Answer

Simplifying object creation

Answer

Improving code readability

Answer

Minimizing memory usage

Question 19

What primary responsibility does the Facade pattern fulfill?

Accepted Answer

Simplifying complex interfaces

Answer

Encapsulating legacy code

Answer

Enforcing access control

Answer

Implementing lazy loading

Question 20

Which design pattern separates object creation from its representation to simplify the construction process?

Accepted Answer

Builder

Answer

Prototype

Answer

Factory Method

Answer

Singleton

Question 21

Which design pattern is specifically designed to ensure that only a single instance of a class is created in an application?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Observer

Answer

Strategy

Question 22

Which design pattern allows objects to subscribe to events and receive notifications when those events occur?

Accepted Answer

Observer

Answer

Mediator

Answer

Facade

Answer

Bridge

Question 23

Which design pattern is used to provide a simplified and unified interface to a set of classes or subsystems?

Accepted Answer

Facade

Answer

Decorator

Answer

Adapter

Answer

Proxy

Question 24

What is the key difference between the Decorator and Proxy patterns?

Accepted Answer

Decorators add functionality to an object, while proxies control access to it

Answer

Proxies add functionality to an object, while decorators control access to it

Answer

Decorators are applied dynamically, while proxies are statically applied

Answer

Proxies are applied dynamically, while decorators are statically applied

Question 25

What is a key benefit of using the Bridge pattern?

Accepted Answer

Decoupling an abstraction from its implementation

Answer

Simplifying the creation of complex objects

Answer

Promoting code reusability through inheritance

Answer

Enforcing a single interface for all client access

Question 26

Which design pattern allows for the creation of hierarchical structures of objects that can be manipulated as a single unit?

Accepted Answer

Composite

Answer

Decorator

Answer

Observer

Answer

Facade

Question 27

Which design pattern resolves compatibility issues between objects with mismatched interfaces by employing an intermediary class?

Accepted Answer

Adapter Pattern

Answer

Decorator Pattern

Answer

Strategy Pattern

Answer

Builder Pattern

Question 28

Which design pattern allows for the independent modification of a class's interface and implementation?

Accepted Answer

Bridge

Answer

Adapter

Answer

Decorator

Answer

Builder

Question 29

Which design pattern allows you to add functionality to an object without changing its structure?

Accepted Answer

Decorator Pattern

Answer

Singleton Pattern

Answer

Factory Method Pattern

Answer

Composite Pattern

Question 30

In event-driven systems, which design pattern is ideal for automatically updating objects when the state of another object changes?

Accepted Answer

Observer

Answer

Singleton

Answer

Factory Method

Question 31

Identify the design pattern that encapsulates object creation, enabling subclasses to modify the type of object that will be instantiated:

Accepted Answer

Factory Method

Answer

Prototype

Answer

Builder

Answer

Abstract Factory

Question 32

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

Accepted Answer

Singleton

Answer

Strategy

Answer

Observer

Answer

Factory Method

Question 33

Identify the pattern that enables the composition of objects into tree structures, representing part-whole hierarchies:

Accepted Answer

Composite

Answer

Strategy

Answer

Builder

Answer

Decorator

Question 34

Which design pattern provides a way to dynamically attach additional responsibilities to an object?

Accepted Answer

Decorator

Answer

Bridge

Answer

Adapter

Answer

Proxy

Question 35

Identify the pattern that defines the skeleton of an algorithm in an object while deferring specific steps to subclasses:

Accepted Answer

Template Method

Answer

Strategy

Answer

Facade

Answer

Decorator

Question 36

Which pattern encapsulates a request as an object, allowing it to be parameterized, queued, or logged, and executed independently?

Accepted Answer

Command

Answer

Observer

Answer

Mediator

Answer

Iterator

Question 37

Identify the design pattern that defines how a set of objects interact with each other to achieve a common goal:

Accepted Answer

Mediator

Answer

Observer

Answer

Command

Answer

Template Method

Question 38

Which pattern defines an interface for iterating over a collection of objects without exposing its underlying representation?

Accepted Answer

Iterator

Answer

Observer

Answer

Mediator

Answer

Composite

Question 39

Which design pattern enables loose coupling between objects, allowing them to be notified of changes in each other's state?

Accepted Answer

Observer

Answer

Mediator

Answer

Command

Answer

Iterator

Question 40

Which design pattern involves one object delegating a request to another object for processing?

Accepted Answer

Command

Answer

Adapter

Answer

Factory Method

Answer

Singleton

Question 41

What design pattern ensures that a class can only have one instance, providing global access while preventing multiple instances?

Accepted Answer

Singleton

Answer

Observer

Answer

Composite

Answer

Chain of Responsibility

Question 42

The code snippet `public class Context { private Strategy strategy; }` demonstrates which design pattern?

Accepted Answer

Strategy

Answer

Visitor

Answer

Abstract Factory

Answer

Factory Method

Question 43

Which design pattern is best suited for creating, composing, and representing a family of related objects as a single object?

Accepted Answer

Composite

Answer

Mediator

Answer

Builder

Answer

Decorator

Question 44

Which design pattern allows objects to communicate without knowing each other's specific relationships?

Accepted Answer

Observer

Answer

State

Answer

Bridge

Answer

Decorator

Question 45

The code `public interface Flyable { void fly(); }` exemplifies which design pattern?

Accepted Answer

Strategy

Answer

Template Method

Answer

Composite

Answer

Adapter

Question 46

What design pattern allows you to change an object's interface to another interface without altering the original object?

Accepted Answer

Adapter

Answer

Chain of Responsibility

Answer

Decorator

Answer

Composite

Question 47

Which design pattern introduces an intermediary class to handle communication between a sender and receiver, decoupling them?

Accepted Answer

Mediator

Answer

Observer

Answer

Memento

Answer

Visitor

Question 48

Which design pattern allows for the storage of an object's state in a way that can be restored later, without affecting other system objects?

Accepted Answer

Memento

Answer

Singleton

Answer

Chain of Responsibility

Answer

Command

Question 49

Which design pattern represents a one-to-many dependency between objects, where a change in one object causes a corresponding change in all dependent objects?

Accepted Answer

Observer

Answer

Adapter

Answer

Factory Method

Answer

Singleton

Question 50

Which design pattern provides a common interface for interchangeable objects, enabling clients to compose objects without specifying their concrete classes?

Accepted Answer

Strategy

Answer

Observer

Answer

Decorator

Answer

Adapter

Question 51

Which design pattern allows for the dynamic composition of objects to represent complex structures that can be easily modified?

Accepted Answer

Composite

Answer

Factory Method

Answer

Singleton

Answer

Proxy

Question 52

Which design pattern ensures that a class has only one instance, controlling its instantiation and providing a single, global point of access to it?

Accepted Answer

Singleton

Answer

Observer

Answer

Builder

Answer

Factory Method

Question 53

Which design pattern provides a way to add additional functionality to an object without modifying its source code, enabling flexible extension and customization?

Accepted Answer

Decorator

Answer

Proxy

Answer

Composite

Answer

Adapter

Question 54

Which design pattern represents an object that acts as an intermediary between a client and a target object, controlling access to the target and protecting it from external influences?

Accepted Answer

Proxy

Answer

Singleton

Answer

Adapter

Answer

Decorator

Question 55

Which design pattern provides a way to create new objects that are similar to existing objects, avoiding the need to create them from scratch, promoting code reusability and efficiency?

Accepted Answer

Prototype

Answer

Adapter

Answer

Factory Method

Answer

Builder