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.
Typically one would create a class to represent the "shopping cart" - an instance would be stored in a session so it could be used by both servlets and JSP. You also have a class to represent catalog items. Bill