Singleton Class (ConfigurationManager):?

Short answer: The ConfigurationManager class is designed to ensure that there is only one instance of it throughout the application.

Explain a bit more

The Instance property handles the lazy initialization of the singleton instance, ensuring that it's only created once and then reused.

Example code

{
private static ConfigurationManager _instance;
private static readonly object _lock = new object(); // Lock
for thread safety
private ConfigurationManager() { } // Private constructor to prevent instantiation public static ConfigurationManager Instance
{ get { lock (_lock) // Ensure thread safety {
return _instance ??= new ConfigurationManager(); // Lazy initialization }
}
}

Real-world example (ShopNest)

Use a GoF pattern in ShopNest only when it removes duplication or makes a change safer—explain the problem it solves in the interview.

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.