Tomcat thread pool usage schema

I'm developing servlet filter intended to manage some resources which should be available during servlet processing. Since I'm not very familiar with the Tomcat, I have some doubt. Is it guaranteed that, for single request, all attached filters and the servlet itself are processed by single (and the same)开发者_运维知识库 thread? In other words: can I assume that FilterChain.doFilter() method doesn't use different thread than its caller?

Yes, this is guaranteed by the servlet specification.