Usually, the process starts with a telephonic round. In the first face-to-face round, they began with heavily core Java questions. Most of us had never imagined the type of questions asked. I did not pass the first round. They asked a few DB questions. The core Java questions were too deep, mostly on performance tuning. It was a very nice experience, even though I lost in the first round itself. They observe how you approach the problem.

How do you manage session details for the recent 10 most active users? Which collections do you use for this?