How are the implicit object made available in the jsp file? Where are they defined?

There are nine implicit variables in JSP : Application ,session,request,response,out,page,pageContext,config,exception.

The objects that these variables refer created by servlet container and are call implicit Objects: They are as follows:

ServletContex ,HttpSession ,HttpServletRequest, HttpServetResponse, JspWriter, ServletConfig,Object

In _jspService() method of generated servlet of JSP you can implicity find these variables

i didnt get you. That way of explanation. We are good if you give the clean picture