JSP total of the following nine built-in objects:
Request the HttpServletRequest instance of the class, the client request, the request will include parameters from GET / POST request
the Response HttpServletResponse instance of the class, page response back to the client
OUT the PrintWriter instance of a class, for outputting the result to the web
the session the HttpSession instance of the class associated with the request of the session
the Application the ServletContext instance of a class, and application-related context, servlet executing content
config the ServletConfig instance of the class, servlet framework member
pageContext PageContext instance of the class, the JSP page provides access to all the objects and namespaces
page JSP page itself, similar to this keyword in the Java class
Exception Exception class object representing abnormal subject error JSP page corresponds to