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.
While container shuts down, request listeners, session listeners an finally contextlisteners are expunged. Session tracking cookies are not deleted because they are present on client machine. Cookies generally are sent back and forth from client and received by server (after first request to create). So even if you log off from site or close the browser (virtually away from container) then also in the browsers history, you can find the cookies present.