code: public static <T extends Watermark> T convertJsonToWatermark(JsonElement jsonElement, Class<T> clazz) {
      return GSON.fromJson(jsonElement, clazz);
    }
docs: Converts a {@link JsonElement} into the specified class type using the {@link Gson#fromJson(JsonElement, Class)}
  method.
  
  @param jsonElement is a {@link JsonElement} that will be converted into a {@link Watermark}.
  @param clazz is the {@link Class} that the {@link JsonElement} will be converted into.
  @return an instance of a class that extends {@link Watermark}.