code: public List<String> getProperties(String json) {
          List<String> properties = new ArrayList<>();
          JsonObject jsonObject = new JsonParser().parse(json).getAsJsonObject();
          for (Map.Entry<String, JsonElement> property : jsonObject.entrySet()) {
              properties.add(property.getKey());
          }
          return properties;
      }
docs: TODO: remove gson support here