NPCI Full Stack Engineer interview experience

From there, the questions stayed anchored in fundamentals of core Java and OOP—things like inheritance, and how I’d implement it in a small Java program. I remember having to explain the code clearly, not just what it does but how the pieces fit together.

The discussion also went deeper into a couple of classic topics that felt very “Java internals” focused. I was asked about the diamond problem, and then we shifted to how HashMap works under the hood. Near the end, the interview turned slightly more front-end: I got a React-related question about how form validation is implemented, which