Добрый день! На мой взгляд решение проходит по условиям, однако проверку не проходит. Не могу понять почему. public class Solution { public static void main(String[] args) throws IOException { if (args.length == 0) return; String fileName = args[1]; File dir = new File(args[0]); File file = new File(fileName); File newFile = new File(file.getParent() + "//allFilesContent.txt"); if (FileUtils.isExist(file)) FileUtils.renameFile(file, newFile); List<File> list = new ArrayList<>(); readDir(dir, list); list.stream() .sorted() .forEach(s -> { try (FileInputStream stream = new FileInputStream(s); FileOutputStream outputStream = new FileOutputStream(newFile, true)) { while (stream.available() != 0) { outputStream.write(stream.read()); } outputStream.write("\n".getBytes()); } catch (IOException e) { e.printStackTrace(); } }); } public static void readDir (File dir, List<File> list) throws IOException { File[] files = dir.listFiles(); assert files != null; for (File file : files) { if (file.isDirectory()) readDir(file, list); else if (file.length() <= 50) list.add(file); } } }