NIO directory listing

        Path dir = new File(pathname).toPath();
        try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
            for (Path file: stream) {
                System.out.println(file.getFileName());
            }
        } catch (IOException | DirectoryIteratorException x) {
            // IOException can never be thrown by the iteration.
            // In this snippet, it can only be thrown by newDirectoryStream.
            System.err.println(x);
        }