HFSJ final mock exam ques - 55

[Shruthi Karthick]

can someone explain me how the answer is BBUBUB?
If attribute key is already present in the session and if we call setAttribute on the same "key" is that equivalent to " removeAttribute(oldvalue) + setAttribute(new value)?
Pls clarify me..

[Nitin Vashishtha]

Originally posted by Shruthi Karthick:

If attribute key is already present in the session and if we call setAttribute on the same "key" is that equivalent to " removeAttribute(oldvalue) + setAttribute(new value)?

Yes,if you set an attribute and one attribute already exists with that name, the new value will replace the old value for that attribute.

[Shruthi Karthick]

can you explain how the answer is BBUBUB

[Joshua Antony]

Just gave mock exam, I too have same doubt, somebody please clarify

[Joshua Antony]

Here is the code :

In servlet...

req.getSession().setAttribute("key",new X());
req.getSession().setAttribute("key",new X());
req.getSession().setAttribute("key","x");
req.getSession().removeAttribute("key");

X is a listener implementing HttpSessionBindingListener

in valueBound method it prints B
in valueUnbound method it prints UB

[Christophe Verré]

I remember some ranchers saying that they had different results depending on whether they use Websphere or Tomcat (here)