page

The named object is available from the 

javax.servlet.jsp.PageContext

 for the current page.

This reference shall be discarded upon completion of the current 

request by the page body.

It is illegal to change the instance object associated, such that its 

runtime type is a subset of the type of the current object previously 

associated.

request

The named object is available from the current page's 

ServletRequest

 object using the 

getAttribute(name)

method.

This reference shall be discarded upon completion of the current client 

request.

It is illegal to change the value of an instance object so associated, 

such that its runtime type is a subset of the type(s) of the object 

previously so associated.

session

The named object is available from the current page's 

HttpSession 

object (which can in turn be obtained from the 

ServletRequest

object) using the 

getValue(name)

 method.

This reference shall be discarded upon invalidation of the current 

session.

It is Illegal to change the value of an instance object so associated, 

such that its new runtime type is a subset of the type(s) of the object 

previously so associated.

Note it is a fatal translation error to attempt to use 

session

 scope 

when the JSP page so attempting has declared, via the 

<%@ page 

... %>

 directive (see later) that it does not participate in a 

session

.

application

The named object is available from the current page's 

ServletContext

 object using the 

getAttribute(name)

method.

This reference shall be discarded upon reclamation of the 

ServletContext

.

It is Illegal to change the value of an instance object so associated, 

such that its new runtime type is a subset of the type(s) of the object 

previously so associated.

Chapter 2

Standard Syntax and Semantics

60