ServletCongig object is per servlet or jsp which contains specifiv information about that servlet or jsp. you can pass this information in the web.xml file's <init-param> tag of the <servlet-tag>.
ServletContext object for the application per JVM. You can pass input to this object from the web.xml file using the <context-param> in the <web-app> tag. This object can be accessed by all the web components as it is one per JVM.
ServletConfig object of one servlet or jsp can not be accessed by other web component.