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.
In MVC, the JSP is the last thing that happens in a request. By the time you hit another action, the request is over and all your request attributes are gone. Which explains the null. Why not pass the value as a parameter to the action?