Total of four rounds: two technical, one managerial, and one HR.

Both technical and managerial rounds were good and mostly asked questions from core Java and Diameter. The interviewers were polite and friendly.

The worst part was the HR round. In my four years of professional career, I have never encountered someone like him. Firstly, I was informed a day before the F2F round, so I didn't update my resume. I informed the HR who scheduled my interview about my updated expected package, and she told me there was no issue with the old resume and package.

But at the company, the HR was different, and he was so rude. He was negotiating the salary like a fish market. Even when I was talking to him politely, he was yelling at me and kept saying, "Don't argue with me."

I was literally stunned to see such people who handle employees.

Inheritance, polymorphism, and generics.

BST, data structures, and collections.