it ignores those, for good reason
Also, the servlet API is crazy, partly because of all its baggage. There seems to be a lot of exploration around what the right API is right now, but its pretty clear the world wants something new.
No. Servlet containers use a thread pool (that grows and shrinks dynamically).
The point is that a given request in a servlet container is handled in it's own thread. That thread will probably come from a pool and be reused to handle another request of course, but that's sort of immaterial.