What is the difference between Cohesion and Coupling?

Short answer: Cohesion: Degree to which elements of a module belong together. High cohesion means focused, well-defined responsibilities. Coupling: Degree of interdependence between modules. Low coupling means modules are independent and changes in one don’t affect others.

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.