Can you explain the difference between lazy and eager initialization in Singleton?

Short answer: Eager Initialization: The Singleton instance is created at the time of class loading. It's simple but can waste resources if the instance is never used. Lazy Initialization: The instance is created only when it is first accessed. It saves resources but requires careful implementation for thread safety. Factory pattern Q&A

Real-world example (ShopNest)

ShopNest payment fees use Strategy: IFeeCalculator with UPI/Card implementations chosen at runtime.

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.