JSP Implicit Objects

JSP implicit objects are created during the translation phase of JSP to the servlet and it is created by the web container.

JSP implicit objects can be accessed using objects and these objects can be directly used in scriplets that goes in the service method.

Types:

There are 9 types of  jsp implicit objects,they are 

request implicit object

The JSP implicit request object is type of javax.servlet.http.HttpServletRequest interface. It represents the request made by the client. It can be used to get request information such as parameter, header information, remote address, server name, server port, content type, character encoding etc.It is used to get,set or remove attribute from the request scope.

response implicit object

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. It can be used to add or manipulate response such as redirect response to another resource, send error etc.

out implicit object

The JSP implicit out object is type of  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.

session implicit object

The JSP implicit session object is an instance of a java class that implements the javax.servlet.http.HttpSession interface. It is used  to set,get or remove attribute or to get session information.. The session implicit object is used to store session state for a single user.

application implicit object
The JSP implicit application object is an instance of a java class that implements the javax.servlet.ServletContext interface.This object can be used to get initialization parameter from configuration file(web.xml).This initialization parameter can be used by all jsp pages and also it is used to get,set or remove attribute from the application scope.

exception implicit object

The JSP implicit exception object is type of java.lang.Throwable class. It is available in JSP error pages only. it can be used to print the exception and It represents the occured exception that caused the control to pass to the JSP error page.

config implicit object
The JSP implicit config object is an instance of a java class that implements the javax.servlet.ServletConfig interface.This object can be used to get initialization parameter for a particular JSP page  from configuration file(web.xml).The config
object is created by the web container for each jsp page.

page implicit object

The JSP implicit page object is type of  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 less used because it consumes large memory.

pageContext implicit object

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

The pageContext object can be used to set,get or remove attribute from one of the following scopes,they are  page request session application Note:

In JSP, page scope is the default scope.