types of implicit variabless

[Yu Chen]

Question ID :997967667647
For the JSP scopes of request and page, what type of object is used to store the attributes?
1. HttpServletRequest and ServletContext respectively
2. ServletRequest and ServletConfig respectively
3. ServletRequest and PageContext respectively
4. HttpServletRequest and PageContext respectively
5. ServletConfig for both
I would say (Http)ServletRequest and Object respectively, but the answer is 3?? In Manning's study kit, it states that the implicit variables are of type/class:
application: ServletContext
session: HttpSessoin
request: HttpServletRequest
response: HttpServletResponse
out: JspWriter
page: Object
pageContext: PageContext
config: ServletConfig
exception: Throwable

Any thoughts?
Thanks,
-yu chen

[Anthony Villanueva]

Attributes of request scope are stored in ServletRequest objects, while attributes of page scope are stored in PageContext objects. The implicit object "page" is not the same as the "pageContext" object.
In the JSP 1.2 specs:

JSP.2.8.4 The pageContext Object
A PageContext is an object that provides a context to store references to objects
used by the page, encapsulates implementation-dependent features, and provides
convenience methods...

whilst the implicit object page is

The instance of this page’s implementation class processing the current request.

[Yu Chen]

Thanks, that is a important concept. It makes sense now.
-yu chen