code: private static @Nullable Collection<IOException> deleteDirectoryContentsInsecure(
        DirectoryStream<Path> dir) {
      Collection<IOException> exceptions = null;
      try {
        for (Path entry : dir) {
          exceptions = concat(exceptions, deleteRecursivelyInsecure(entry));
        }
  
        return exceptions;
      } catch (DirectoryIteratorException e) {
        return addException(exceptions, e.getCause());
      }
    }
docs: Simple, insecure method for deleting the contents of a directory for file systems that don't
  support {@code SecureDirectoryStream}. Returns a collection of exceptions that occurred or null
  if no exceptions were thrown.