The servlet mapping specifies which web container of the Java servlet should be invoked for a given URL. It maps the URL patterns to servlets. When there is a request from a client, the servlet container decides which servlet it should forward the request to based on the servlet mapping. In our case, we mapped all incoming requests to DispatcherServlet.

In contrast, request mapping guides the DispatcherServlet which controller method it needs to invoke as a response to the request based on the request path. In our case, we mapped the /welcome request path to the welcome method of the HomeController class.

@Override 
protected String[] getServletMappings() { 
   return new String[] { "*.do"}; 
} 

@Override 
protected String[] getServletMappings() { 
   return new String[] { "/"}; 
}