static String makeRandomID(int length) {
  ret makeRandomID(length, defaultRandomGenerator());
}

static String makeRandomID(int length, Random random) {
  char[] id = new char[length];
  for (int i = 0; i < id.length; i++)
    id[i] = (char) ((int) 'a' + random.nextInt(26));
  return new String(id);
}

sS makeRandomID(Random r, int length) {
  ret makeRandomID(length, r);
}