A servlet mapping is a correspondence between a client request and a servlet.
Servlet containers use URL paths to map client requests to servlets, and follow the URL path-mapping rules as specified in the Java Servlet specification. The container uses the URI from the request, minus the context path, as the path to map to a servlet. The container chooses the longest matching available context path from the list of web application (.war)s that it hosts.
See AlsoWebapplications: Resources for learning