A ServletConfig object provides access to JSP or servlet specific initialization parameters and to a servlet context. It can also give you the name of the servlet or JSP as defined in the deployment descriptor.
A servlet or JSP is only destroyed when the application or container is shut down, or when the container decides to unload the JSP or servlet for some reason. (It may do this for performance.) They are not destroyed at the end of processing a request; remember that Web components are often reused.