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