public void removeUrl(String url){
  Set<String> urls=getCachedUrls();
  urls.remove(url);
  putCachedUrls(urls);
  updateNotification(urls);
}

public void removeUrl ( String url ) { Set < String > urls = getCachedUrls ( ) ; urls . remove ( url ) ; putCachedUrls ( urls ) ; updateNotification ( urls ) ; }
remove a url to the store of urls . this method additionally updates the physical web notification .
