I read that the container creates for each request captured a thread. I know that one thread is generated to handle one Servlet instance, if you have ten started Servlets and all up, so you got one thread for each Servlet started, but for each request do you have addicional threads running?
Yes, assuming that you have 10 diferent servlets in your webapp then the container will create/allocate 1 thread per request, independently of what servlet will serve that request.
To answer your questions, if servlet implements Single Thread Model then vendor can implement STM by creating multiple instances of servlet and make sure that every sevlet instance creates only one thread at a time.