Design a Java service that handles thousands of requests per second and, for each one, calls several slow external systems. How would you organize threads, pools, and overload protection?
~10 min by voice
How to approach it
This checks whether the candidate can design an I/O-heavy service so that a slow dependency doesn't take the whole thing down: deliberately choosing a threading model, limiting concurrency, setting timeouts and failing fast instead of piling up a queue.
The interviewer will ask this question and listen. Think out loud and ask for a hint if you need one. When you're done, pause or tap “That's my answer”. In about a minute, your score and the points you covered show up here.