static private Collection<URL> readURLs(final File file) throws IOException {
  final Collection<URL> urls=new LinkedList<URL>();
  if (file.isDirectory()) {
    final File[] files=file.listFiles();
    for (    File f : files) {
      if (f.isHidden())       continue;
      urls.addAll(readURLsFromFile(f));
    }
  }
 else {
    urls.addAll(readURLsFromFile(file));
  }
  return urls;
}

static private Collection < URL > readURLs ( final File file ) throws IOException { final Collection < URL > urls = new LinkedList < URL > ( ) ; if ( file . isDirectory ( ) ) { final File [ ] files = file . listFiles ( ) ; for ( File f : files ) { if ( f . isHidden ( ) ) continue ; urls . addAll ( readURLsFromFile ( f ) ) ; } } else { urls . addAll ( readURLsFromFile ( file ) ) ; } return urls ; }
reads urls from a file or all files ( recursively ) in a directory .
