ServletContext Defines a set of methods that a
servlet uses to communicate with its servlet container.
ServletConfig is a servlet configuration object used by a servlet container used to pass information to a servlet during initialization. All of its initialization parameters can ONLY be set in deployment descriptor.
The ServletContext object is contained within the ServletConfig object, which the Web server provides the servlet when the servlet is initialized.
You can specify param-value pairs for ServletContext object in <context-param> tags in web.xml file.