Advanced Concepts and Design Principles Interview Questions | OOPS | NextRound

1What are the SOLID principles? Explain each briefly.Intermediate

2Explain the Single Responsibility Principle (SRP) with an example.Intermediate

3Explain the Open/Closed Principle (OCP). How do you achieve it without modifying existing code?Intermediate

4Explain the Liskov Substitution Principle (LSP). What happens if it's violated? (Square/Rectangle problem)Intermediate

5Explain the Interface Segregation Principle (ISP). Why are fat interfaces bad?Intermediate

6Explain the Dependency Inversion Principle (DIP). How does it relate to Dependency Injection?Intermediate

7What is the difference between Aggregation and Composition?Intermediate

8What is the Factory Pattern? How does it help in achieving OCP?Intermediate

9What is the Abstract Factory Pattern? How does it differ from Factory Method?Intermediate

10What is the Strategy Pattern? How does it replace complex conditional logic?Intermediate

11What is the Observer Pattern? Where is it used in real life? (Event handling, Pub/Sub)Intermediate

12What is the Decorator Pattern? How does it add functionality dynamically?Intermediate

13What is a Singleton Pattern? What are the thread-safety concerns and how to handle them?Intermediate

14What is an Anti-Pattern? Can you name a few? (God Object, Spaghetti Code, Golden Hammer)Intermediate

15What is "Coupling" and "Cohesion"? Explain the relationship between them.Intermediate

16What are Generics/Templates? How do they improve type safety and performance compared to casting?Intermediate

17What is Type Erasure (Java) vs Reified Generics (C#)?Intermediate

18What is Variance in Generics? (Covariance and Contravariance)Intermediate

19What are Extension Methods (C#) or Default Methods (Java)? When should you use them?Intermediate

20What is Reflection? How can it be used to break Encapsulation? What are the performance costs?Intermediate

21What is the "Law of Demeter"? (Don't talk to strangers)Intermediate

22Explain "Tell, Don't Ask" principle.Intermediate

23What is the DRY principle? How does OOP help achieve it?Intermediate

24What is the YAGNI principle?Intermediate