public static void addServlet(WebXml webXml,Servlet element){
  if (element == null) {
    throw new NullPointerException();
  }
  webXml.addTag(element);
}

public static void addServlet ( WebXml webXml , Servlet element ) { if ( element == null ) { throw new NullPointerException ( ) ; } webXml . addTag ( element ) ; }
add a servlet to the web xml .
