the methods in Http Handlers are-
1.ProcessRequest- used to call HttpRequests
IsReusable - for checking the same instance handler's reusability
along with a new same type request.

how you will configure Http Handlers?
to map incoming URLs to the IHttpHandler or the IHttpHandlerFActory
classes the configuration section handler is used.It may be defined
at the application level,website,or computer.

tag directives are used to configure section by the adminitrators.
these directives are processed in the order of top-down.the
following syntax is used for section handler-

<httpHandlers>
<add verblist="[verb list]" paths="[path/wildcard]" types="[COM+ Class],
[Assembly]" validate="[TRUE/FALSE]" />
<remove verblist="[verb list]" paths="[path/wildcard]" />
<clear />
</httpHandlers>

creating a HTTP handler involves implementing the IHttpHandler interface.
there are one property and method of IHttpHandler interface with to signa-
ture-
void ProcessRequest(HttpContext);
bool IsReusable {get;}