code: public void addServlet(Servlet servlet, String uri) {
          // create a holder and then add it to the mapping
          ServletHolder servletHolder = new ServletHolder(servlet);
          rootServletContext.addServlet(servletHolder, uri);
      }
docs: Adds a servlet to this server.
  @param servlet The servlet to add
  @param uri The uri mapping (relative to root context /) to trigger this
  servlet to be executed. Wildcards are permitted.