This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I don't understand why there is a difference between how a Web Container manages a Servlet (only one instance / one thread per request) and how a EJB Container manages a Stateless Session Bean (pool of instances).
I had this whole thing typed out for you, but I deleted it --- I really have no idea why SSBs aren't just done one per type and have multiple threads executing within it. I suppose it's just a spec nuance.