What are the implicit objects in jsp?

At the time when the container builds the service method, the container declares and initializes all the implicit objects. These makes JSP to take advantage of servletness, i.e. sdirectly use some important servlet objects in your jsp(without creating instance of that class). Some facts How did the jsp get the init parameters and context parameters, how jsp get the session, how did your jsp get the parameters from the client, these forces to use the implicit objects.

API- Implicit objects
jspWriter- out
HttpServletRequest- request
HttpServletResponse- response
HttpSession- session
ServletContext- application
ServletConfig- config
Throwable- exception
PageContext- pageContext
Object- page

A pagecontext encapsulates other implicit objects, so if you give some helper object a pagecontext reference, the helper can use that reference to get reference to other implicit objects and attributes from all scopes.