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Test Quiz & Challenge

Photo of ncg_wp ncg_wpOctober 7th, 2025Last Updated: November 11th, 2025
0 821 Less than a minute

Lets start with a quiz!

Design patterns are reusable solutions to common problems in software design, providing a structured approach to writing maintainable, scalable, and efficient code. This quiz focuses on Java design patterns, covering creational, structural, and behavioral patterns as defined in the Gang of Four (GoF) book, along with their practical applications in Java. It is tailored for advanced Java developers who are familiar with object-oriented programming principles and have experience applying design patterns in real-world projects.

This quiz challenges your deep understanding of Java design patterns, testing your ability to recognize, implement, and critique their use in complex scenarios. By taking this quiz, you will:

  • Reinforce your knowledge of creational, structural, and behavioral patterns.
  • Sharpen your ability to choose the right pattern for specific design problems.
  • Identify common pitfalls and anti-patterns in pattern implementation.
  • Gain confidence in applying design patterns to optimize Java codebases.
  • Receive feedback on correct and incorrect answers to deepen your understanding.

This quiz features 15 questions. Try to answer as many as possible and submit to see your results. Good Luck!

Notice: You must log in or register to have your score calculated, earn points, save quiz history, and view detailed results.

1. Which design pattern is best suited for creating an object when the creation process is complex and involves multiple steps?

 
 
 
 

2. In the Singleton pattern, which approach ensures thread safety in a multi-threaded Java environment without excessive synchronization overhead?

 
 
 
 

3. Which of the following statements are true about the Factory Method pattern?
Select all that apply.

 
 
 
 

4. In the Observer pattern, what is the role of the Subject in a Java implementation?

 
 
 
 

5. Which design patterns are commonly used to manage object creation in Java?
Select all that apply.

 
 
 
 
 

6. Which pattern would you use to add responsibilities to an object dynamically without modifying its code?

 
 
 
 

7. In a Strategy pattern implementation, which Java feature is most commonly used to define interchangeable algorithms?

 
 
 
 

8. Which of the following are benefits of the Adapter pattern?
Select all that apply.

 
 
 
 

9. What is a key difference between the Proxy and Decorator patterns in Java?

 
 
 
 

10. Which patterns are classified as Behavioral patterns?
Select all that apply.

 
 
 
 
 

11. When implementing the Command pattern in Java, which component encapsulates a request as an object?

 
 
 
 

12. Which of the following are true about the Composite pattern?
Select all that apply.

 
 
 
 

13. In the Abstract Factory pattern, what is the primary purpose of the factory interface?

 
 
 
 

14. Which patterns can be used to reduce coupling in a Java application?
Select all that apply.

 
 
 
 
 

15. Which pattern is most appropriate for implementing a system where objects need to be copied or cloned efficiently?

 
 
 
 

Question 1 of 15

Implementing a Singleton Pattern

Your task is to implement the Singleton design pattern in Java.Create a static class named MySingleton with a getInstance() method that represents a globally accessible, single-instance utility.This instance should always be the same whenever it’s retrieved, no matter how many times it’s requested.You’re free to decide how to achieve this behavior, but the result must be consistent with the Singleton pattern principles.When you’re done, you can use the provided Main class to test your implementation — our system will automatically verify its correctness.

Implementing a Factory Method Pattern

Your task is to implement the Factory Method design pattern in Java. Create an interface Shape with a draw() method. Implement two concrete static classes, Circle and Square, that implement this interface, each printing a unique message in draw() containing their respective type (circle or square).

Then, implement a static ShapeFactory class with a getShape(String type, int size). This method should return a new instance of Circle or Square depending on the type argument. Respective types must be circle and square.

When you’re done, you can use the provided Main class to test your implementation — our system will automatically verify its correctness.

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Photo of ncg_wp ncg_wpOctober 7th, 2025Last Updated: November 11th, 2025
0 821 Less than a minute
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