Servlet Config as the name suggests, provides Servlet specific configuration information to a particular servlet. For Example :- the information that u specify in the web.xml file like this
Each servlet will have its own servlet config object, which will be specific to that servlet.
ServletContext -------------- It provides application view to all the servlets. There is one ServletContext per JVM for one application. It also provides methods to access application wide parameters specified in <context-param>....</context-param> tag in web.xml.