This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Probably not. This would generally be server dependent. On some servers you would be able to control the total number of simultaneous requests - which would define the thread pool size, or vice versa. But I don't know any that control how many threads can access a single Servlet.