code block for README-6

README-6

// Collect readers from args/stdin
final Stream<BufferedReader> readers;
if (args.length > 0) {
  readers = Arrays.stream(args)
    .map(filename -> {
      try {
        return new BufferedReader(
          new FileReader(filename));
      } catch (Exception e) {
        // No lambda checked exceptions
        throw new RuntimeException(e);
      }
    });
} else {
  readers = Stream.of(
    new BufferedReader(
     new InputStreamReader(System.in)));
}
// Swallow all readers into one string
final var content = readers
  .flatMap(BufferedReader::lines)
  .collect(Collectors.joining("\n"));