All JSP containers must support HTTP as a protocol for requests and responses, but a 
container may also support additional request/response protocols. The default request and 
response objects are of type 
HttpServletRequest
 and 
HttpServletResponse
, 
respectively.
A JSP page may also indicate how some events are to be handled. In JSP 1.1 only 
init
 and 
destroy 
events can be described: the first time a request is delivered to a JSP page a 
jspInit()
method, if present, will be called to prepare the page. Similarly, a JSP container can reclaim 
the resources used by a JSP page at any time that a request is not being serviced by the JSP 
page by invoking first its 
jspDestroy()
 method; this is the same life cycle as that of 
Servlets.
A JSP page is represented at request time by a 
JSP page implementation class 
that 
implements the 
javax.servlet.Servlet
interface. JSP pages are often implemented 
using a JSP page 
translation phase
 that is done only once, followed by some 
request 
processing phase
 that is done once per request. The translation phase creates the JSP page 
implementation class. If the JSP page is delivered to the JSP container in source form, the 
translation of a JSP source page can occur at any time between initial deployment of the JSP 
page into the runtime environment of a JSP container and the receipt and processing of a 
client request for the target JSP page.
A JSP page contains some 
declarations
, some 
fixed template
 data, some (perhaps nested) 
action instances,
 and some 
scripting elements
. When a request is delivered to a JSP page, all 
these pieces are used to create a response object that is then returned to the client. Usually, 
the most important part of this response object is the result stream.
1.4.2
Compiling JSP Pages
JSP pages may be 
compiled
 into its JSP page implementation class plus some deployment 
information. This enables the use of JSP page authoring tools and JSP tag libraries to author 
a Servlet. This has several benefits:
Removal of the start up lag that occurs when a JSP page delivered as source receives the 
first request.
Reduction of the footprint needed to run a JSP container, as the java compiler is not 
needed.
If a JSP page implementation class depends on some support classes in addition to the JSP 
1.1 and Servlet 2.2 classes, the support classes will have to be included in the packaged WAR 
so it will be portable across all JSP containers.
Appendix C contains two examples of packaging of JSP pages. One shows a JSP page that is 
delivered in source form (probably the most common case) within a WAR. The other shows 
how a JSP page is translated into a JSP page implementation class plus deployment 
information indicating the classes needed and the mapping between the original URL that 
was directed to the JSP page and the location of the Servlet.
23
JavaServer Pages 1.1 Specification   November 30, 1999




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