What is Interface Segregation Principle?

Short answer: The Interface Segregation Principle (ISP) states that: Clients should not be forced to depend on interfaces they do not use. This means that interfaces should be small and focused, containing only the methods that are relevant to the implementing class. It prevents "fat" or "bloated" interfaces.

Real-world example (ShopNest)

Patterns in ShopNest should solve a real pain (swappable payments, test seams)—not be added for decoration.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.