Question on EL: If it’s NOT a String literal, it’s evaluated

[Hasnain Javed Khan]

Hello All.
I have a question that is confusing me regarding EL. The following line is taken from HFSJ 2nd Edition

If there are no quotes inside the brackets, the Container evaluates what’s inside the brackets by searching for an attribute bound under that name, and substitutes the value of the attribute

Here is what I tried in a JSP

<%
   session.setAttribute("name","MyName");
%>
	
Name using [] => ${sessionScope[name]} => No Output 
Name using . => ${sessionScope.name} => MyName

No output when using " [] " but got MyName printed when using "." .
Can anyone kindly explain why "name" inside [] cannot be resolved by the container since the attribute "name" is present in session scope ? Am I missing some point/information ?
I'm using tomcat 6.16.

Kind regards.
Hasnain Javed.

[avi sinha]

  <%
   session.setAttribute("name","MyName");
%>
	
Name using [] => ${sessionScope[name]} => No Output 
Name using . => ${sessionScope.name} => MyName
  

here in the first case that is without quotes, container starts looking for an attribute in all the scopes and gets the value MyName.
hence

  ${sessionScope[name]} ---------> ${sessionScope["MyName"]   

and there is no any attribute in the sessionScope named MyName hence nothing is printed.

in the second case container looks for the key named "name" in the map of session attributes. it finds one with the value MyName and is printed.

avi sinha

[Hasnain Javed Khan]

avi sinha wrote:
here in the first case that is without quotes, container starts looking for an attribute in all the scopes and gets the value MyName.
hence

  ${sessionScope[name]} ---------> ${sessionScope["MyName"]   

and there is no any attribute in the sessionScope named MyName hence nothing is printed.

It was so trivial (Thanks to HFSJ => There are no Dumb Questions). It implies I need to give my brain some rest
Thanks Avi .

Kind Regards.
Hasnain.

[avi sinha]

Hasnain Javed Khan wrote:Thanks Avi .
Kind Regards.
Hasnain.

you're welcome

avi sinha