The HttpJspPage interface describes the interaction that a JSP Page Implementation Class must satisfy when using the HTTP protocol.
The behaviour is identical to that of the JspPage, except for the signature of the _jspService method, which is now expressible in the Java type system and included explicitly in the interface.
JspPage
void
_jspService(HttpServletRequest request,
HttpServletResponse response)
public void _jspService(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException
If a superclass is specified using the extends attribute, that superclass may choose to perform some actions in its service() method before or after calling the _jspService() method. See using the extends attribute in the JSP_Engine chapter of the JSP specification.