code: public Map<String, String> toStringMap() {
      Map<String, String> map = new HashMap<>();
      for (Map.Entry<String, Object> entry : entrySet()) {
        map.put(entry.getKey(), String.valueOf(entry.getValue()));
      }
      return map;
    }
docs: Return a copy of the contents of this map as a {@code Map<String, String>}.