question: 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 ; }
target:  Reads URLs from a file or all files (recursively) in a directory.