What is Known as Gang of Four?
The four authors who published the book Design Patterns Elements of Reusable Object-Oriented Software are known as Gang of Four. The name of four authors are Erich Gamma, Ralph Johnson, Richard Hel, and John Vlissides.
Top Design Patterns Interview Questions
A design pattern is basically a reusable and generalized solution to a common problem that arises during software design and development. Design patterns are not specific to a particular programming language or technology instead, they provide abstract templates or blueprints for solving recurring design-related problems. They help software developers create well-structured, maintainable, and flexible code by promoting best practices and proven solutions.
Top Interview Questions for Design Patterns
- 1. What is a Design Pattern?
- 2. What are the types of Design Patterns?
- 3. What are the advantages of using Design Patterns?
- 4. What are the types of creational Patterns?
- 5. What are the types of Structural patterns?
- 6. What are the types of Behavioral patterns?
- 7. What is Known as Gang of Four?
- 8. What is the Singleton pattern, and when would you use it?
- 9. Explain the Factory Method pattern and provide an example of its use.
- 10. Describe the Adapter pattern and provide an example of where it can be applied.
- 11. Provide a scenario where the Command pattern would be preferable to the Strategy pattern.
- 12. Explain the Single Responsibility Principle and its significance in software design.
- 13. What is the Observer pattern, and how does it enable objects to notify others of changes in state?
- 14. Describe the Open/Closed Principle and how design patterns support it.
- 15. How is the Bridge pattern different from the Adapter pattern?
- 16. How does the Dependency Inversion Principle promote loose coupling, and how is it related to design patterns?
- 17. Provide a real-world example of the Singleton pattern being used in a popular library or framework.
- 18. Provide an example where the Strategy pattern is used to switch between different algorithms.
- 19. When should you avoid using design patterns, and what are the potential drawbacks?
- 20. How can you ensure that design patterns do not lead to over-engineering or unnecessary complexity?
- 21. Provide a scenario where the Decorator pattern is used to enhance the functionality of an existing class in a codebase.
- 22. How can the Command pattern be applied in a user interface (UI) framework?
- 23. What is the role of a UML diagram in illustrating design patterns?
- 24. How can design patterns help with refactoring existing code?
- 25. Provide an example where the Strategy pattern is used to switch between different algorithms.