7.2 java

class MyFileVisitor extends SimpleFileVisitor<Path> {
    private ArrayList<Path> paths = new ArrayList<>();

    public ArrayList<Path> getPaths() {
        return paths;
    }

    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
        paths.add(file);
        return FileVisitResult.CONTINUE;
    }
}
public class Utils {

    public static long calculateFolderSize(String path) {
        File mypath = new File(path);
        long length = 0;
        if (!mypath.isDirectory() || !mypath.exists()) throw new IllegalArgumentException();
        for (File file : mypath.listFiles()) {
            length += file.length();
        }
        return length;
    }

    public static void copyFolder(String sourceDirectory, String destinationDirectory) {
        File directory = new File(sourceDirectory);
        Path mainPath = Paths.get(sourceDirectory);
        Path copyDir = Paths.get(destinationDirectory);

        if (!directory.exists()) throw new IllegalArgumentException();
        else
        {
            try{
                if(!Files.exists(copyDir)) Files.createDirectory(copyDir);
                MyFileVisitor myFileVisitor = new MyFileVisitor();
                Files.walkFileTree(mainPath,myFileVisitor);
                for(Path path : myFileVisitor.getPaths()){
                    Path test = new File(destinationDirectory+File.separator+path).toPath();
                    Files.copy(path,new File(copyDir+File.separator+path.getFileName()).toPath(),StandardCopyOption.REPLACE_EXISTING);
                }
            }catch (IOException e)
            {
                e.printStackTrace();
            }

        }
        //TODO реализовать метод копирования папки sourceDirectory в destinationDirectory
    }
}