Explain the JSP Implicit Objects

JSP Implicit objects are created by the web container. These implicit objects are Java objects that implement interfaces in the Servlet and JSP API. Scripting elements in a JSP page can make use of these JSP implicit objects. There are nine (9) JSP implicit objects available.

JSP Implicit Objects are as follows:

1.request

The JSP implicit request object is an instance of a java class that implements the javax.servlet.http.HttpServletRequest interface. It represents the request made by the client. The request implicit object is generally used to get request parameters, request attributes, header information and query string values.
2.response

The JSP implicit response object is an instance of a java class that implements the javax.servlet.http.HttpServletResponse interface. It represents the response to be given to the client. The response implicit object is generally used to set the response content type, add cookie and redirect the response.
3.out

The JSP implicit out object is an instance of the javax.servlet.jsp.JspWriter class. It represents the output content to be sent to the client. The out implicit object is used to write the output content.
4.session

The JSP implicit session object is an instance of a java class that implements the javax.servlet.http.HttpSession interface. It represents a client specific conversation. The session implicit object is used to store session state for a single user.
5.application

The JSP implicit application object is an instance of a java class that implements the javax.servlet.ServletContext interface. It gives facility for a JSP page to obtain and set information about the web application in which it is running.
6.exception

The JSP implicit exception object is an instance of the java.lang.Throwable class. It is available in JSP error pages only. It represents the occured exception that caused the control to pass to the JSP error page.
7. config

The JSP implicit config object is an instance of the java class that implements javax.servlet.ServletConfig interface. It gives facility for a JSP page to obtain the initialization parameters available.
8.page

The JSP implicit page object is an instance of the java.lang.Object class. It represents the current JSP page. That is, it serves as a reference to the java servlet object that implements the JSP page on which it is accessed. It is not advisable to use this page implict object often as it consumes large memory.
9. pageContext

The JSP implicit pageContext object is an instance of the javax.servlet.jsp.PageContext abstract class. It provides useful context information. That is it provides methods to get and set attributes in different scopes and for transfering requests to other resources. Also it contains the reference to to implicit objects.