HFSJ 1st edition mock exam question

[Archana Annamaneni]

This is a HFSJ 1st edition mock exam question .When I took the exam I didn't get it right , someone please explain the answer.

What type of listener could be used to log the user name of a user at the time
that she logs into a system? (Choose all that apply.)

A. HttpSessionListener

B. ServletContextListener

C. HttpSessionAttributeListener

D. ServletContextAttributeListener

[Ryan Beckett]

Not a ServletContextListener. That one fires events when the app is being deployed, before servicing any requests. And, sessions are created automatically and you may not want the user to log in immediately. That leaves HttpSessionAttributeListener and ServletContextAttributeListener.

Note that using the ServletContext for logging seems like a terrible idea, but you can make it work.

[Ranjit Gopinathan]

HttpSessionListener would be ideal I think.

HttpSessionAttributeListener may also be helpful in logging .

I doubt how ServletContextListener can be used to log user login. The callback methods for this interface are for initialization and destruction of the context.

[Abdul Rahman]

Hi,

if the question asks to select one: i'll go for HttpSessionListener. the user name can be logged in the listener's sessionCreated().
if it asks to select 2 then i'll go for HttpSessionListener and HttpSessionAttributeListener. the first one logs all the user logged in. the 2nd one can be used to log the user for his entire session period.

[Archana Annamaneni]

Answer is HttpSessionAttributeListener , I went for HttpSessionListener

Book has following explanation

-Option A is incorrect because the user name would not be
known when the session is initially created. Since logging is
desired at the time of the login, the listener’s invalidation
and timeout methods would not be helpful.
(API)
-Options B and D are incorrect
because these listeners are used for
servlet-context notifications.

I didn't understand why A is not a correct option , session will be created when the user first logged in .HttpSessionListener seems to be correct choice.

Archana