The JSP specification uniformly interprets all these paths in the context of the Web server 

where the JSP page is deployed; i.e. the specification goes through a map translation. The 

semantics applies to translation time phase (i.e. include directives, Section 2.7.6), and to 

request time phase (i.e. to include, Section 2.13.4, and forward, Section 2.13.5,actions).

If a specific tool can ascertain by some mechanism the status of the URL to resource maps at 

deployment time, the tool can take advantage of this information.

With the appropriate assertions, the translation phase might be performed before deploying 

the JSP page into the JSP container.

2.5.3

Web Containers and Web Components

A 

JSP container

 is a system level entity that provides life cycle management and runtime 

support for JSP pages and Servlet components. The term 

Web Container

 is synonymous to that 

a JSP container.

A Web component is either a Servlet or a JSP page.  A web component may use the services 

of its container.  The 

servlet 

element in a 

web.xml

 deployment descriptor is used to 

describe both types of web components; note that most JSP page components are defined 

implicitly in the deployment descriptor through the use of an implicit 

.jsp

 extension mapping.

2.5.4

JSP Pages

A JSP page implementation class defines a 

_jspService()

 method mapping from the 

request 

to the

 response 

object. Some details of this transformation are specific to the scripting 

language used; see Chapter 4. Most details are not language specific and are described in this 

chapter.

Most of the content of a JSP page is devoted to describing what data is written into the 

output stream of the response (usually sent back to the client). The description is based on a 

JspWriter

 object that is exposed through the implicit object

 out

 (see Section 2.8,  Implicit 

Objects ). Its value varies:

Initially, 

out

 is a new 

JspWriter

 object. This object may be different from the stream 

object from 

response.getWriter(),

 and may be considered to be interposed on the latter in 

order to implement buffering (see Section 2.7.1,  The page Directive ). This is the 

initial 

out object. 

JSP page authors are prohibited from writing directly to either the 

PrintWriter

 or 

OutputStream

 associated with the 

ServletResponse

.

Within the body of some actions, 

out

 may be temporarily re assigned to a different 

(nested) instance of 

JspWriter

 object. Whether this is or is not the case depends on the 

details of the actions semantics. Typically the content, or the results of processing the 

content, of these temporary streams is appended to the stream previously referred to by 

41

JavaServer Pages 1.1 Specification  

November 30, 1999