Study the exhibit. What is the result of compiling, deploying and issuing a request to this servlet?
A. The session is invalidate, the userid attribute removed from session-scope and the request returns.
B. A NullPointerException is thron on line 8.
C. An exception is thrown on line 9.
D. An exception is thrown on line 10.
E. A compilation error occurs.
The answer which is given in the book is: C.
Well, for me it looks like it should be E, as there is no casting to String when using HttpSession#getAttribute(-) method which returns an Object.