HF final mock exam Q22

[Jose Esteban]

Today I've made the HF final mock exam (i have the real exam on friday). I don't agree with solution to Q22.
--------------------------------------------------------
Q22. Which JSP code would you use to include static content in a JSP?
A. ...
B. ...
C. <jsp:include page="/segments/footer.html" />
D. ...
--------------------------------------------------------

Option C is marked as true. I think it shouldn't be marked as true, since the content could be dynamic.

In JSP spec (section 5.4) you can read an equivalent example:
<jsp:include page=�/templates/copyright.html�/>
and the spec says:
"It is likely a static object, but it could be mapped into, for instance, a servlet via web.xml."

So, the fact that the extension is .html doesn't mean that it is a static resource, since "/segments/footer.html" could be a totally ficticious name mapped to a servlet via the DD.

What do you think about it?

(BTW, I scored 71% in the HF exam. It's a really hard exam. I hope the real one to be easier )

[Vani Kadur]

Yes. I agree. The answer to Mock Exam Q22 is "A". Only the include directive adds static content in a JSP.

[jiju ka]

What does Option A says. I agree Option C is not right answer.
---------------------------------------
<jsp:include page="somefile" />
---------------------------------------
is a dynamic call.
---------------------------------------
<%@ include file="anothefile" %>
---------------------------------------
is a static call

My assumption is when the page is precompiled a dynamic call is never precompiled even if it is refering to a static page.
[ April 14, 2005: Message edited by: jiju ka ]

[Rafael Pereira]

Well, from one point of view, HFS is not wrong.

<jsp:include> can really be used to include static content in a page!

Which are the other options?

[Jose Esteban]

Originally posted by Vani Kadur:
Only the include directive adds static content in a JSP.

Nope. According to JSP.5.4:
"A <jsp:include .../> action provides for the inclusion of static and dynamic resources in the same context as the current page."

So the include action can also add static content (for example, a HTML page). The question is that writing:

<jsp:include page="/segments/footer.html" />

doesn't mean that you are including the HTML page because, perhaps, the url-pattern "/segments/footer.html" is mapped to a JSP in the DD:

<servlet>
    <servlet-name>test</servlet-name>
    <jsp-file>/someJSP.jsp</jsp-file>
</servlet>
<servlet-mapping>
    <servlet-name>test</servlet-name>
    <url-pattern>/segments/footer.html</url-pattern>
</servlet-mapping>

Then, when the include action is invoked, the container is really including /someJSP.jsp.

Hope this clarifies the answer.

[Jose Esteban]

Originally posted by Rafael Pereira:
Well, from one point of view, HFS is not wrong.

<jsp:include> can really be used to include static content in a page!

Would you use

<jsp:include page="/segments/footer.html" />

to include static content when there's no guarantee that the content included is really static? I wouldn't.

Originally posted by Rafael Pereira:

Which are the other options?

The correct option is:
A. <%@ include file="/segments/footer.html" %>

[Paul Bourdeaux]

OK, this is an argument of semantics. Jose is technically correct, and if this were a real question on the exam he would be able to appeal it. (I think... I have never tried to configure a mapping with that kind of url pattern, but I assume it will work)

However, I think that the mock exam assumes that no extravagant mapping has taken place, and they are trying to reinforce the fact that the <jsp:include> standard action is able to include static content as well as dynamic.

Perhaps you should submit your suggestion to the errata page at oreilly press and have them add a clause like
---------
C. <jsp:include page="/segments/footer.html" /> (Assume that /segments/footer.html is a valid html page and no url remapping has taken place)
---------

[Jose Esteban]

Originally posted by Paul Bourdeaux:
I have never tried to configure a mapping with that kind of url pattern, but I assume it will work

I did it, and it works.

Originally posted by Paul Bourdeaux:
However, I think that the mock exam assumes that no extravagant mapping has taken place,

Too much assumption for an exam!! Moreover, Spec JSP.5.4 warns explicity about this possibility:
"<jsp:include page="/templates/copyright.html"/>
It is likely a static object, but it could be mapped into, for instance, a servlet via web.xml."

Originally posted by Paul Bourdeaux:
... have them add a clause like
---------
C. <jsp:include page="/segments/footer.html" /> (Assume that /segments/footer.html is a valid html page and no url remapping has taken place)
---------

I agree. It would be a correct wording.

[Paul Bourdeaux]

OK, I opened my copy of the specs, and I have to conceed that Jose is absoluty correct. Looking closely at the answer, there is no explanation for Answer C like therre is for Answer A, so I believe it was erronously marked.

I am going to submit it as errata at the O'Reilly HFS&J page. Good catch Jose.

[Paul Bourdeaux]

As promised, I sumbitted an errata, and recieved the following response. I thought I would post it here as well.

>Reporter: Paul Bourdeaux
> Email: [e-mail]
> Title: Head First Servlets and JSP
> Page: 810
> Location: Answer to Question 22
> Severity: serious technical mistake
>
> ======================= Description =======================
>
> [810] Answer to Question 22;
> Answer C is incorrectly marked as a right answer. According to the
> JSP 2.0 Specs, section 5.4 page 1-109, the included object is
> "likely a static object, but it could be mapped ito, for instance,
> a servlet via web.xml." There is no way to tell if
> /segments/footer.html is static or dynamic, therefore Answer C is
> incorrect.
>
> The only correct answer is Answer A.

Date: Sun, 1 May 2005 13:04:28 -0700 (PDT)
From: Bryan Basham

No errata.

This question is not meant to make the reader challenge whether
the URL "/segments/footer.html" is truly static or if it has
been mapped to some servlet. That is not the point of the
question. The point is whether the include directive *as well as* the
include action can include static content. The answer is "yes, they
both permit static content", so both A & C are valid options.

[Kejal Shah]

guys, i'm a bit relieved. I hope such stupid ques don't pop up on my test. I had posted a message regarding the same question, cos while taking the test, even i marked ONLY A.

Anyways, i find teh question no. 55 also errorneous. Any help on tat front?