code: public String stringify(JsonNode json) {
          try {
              return mapper().writerWithDefaultPrettyPrinter().writeValueAsString(json);
          } catch (JsonProcessingException e) {
              throw new RuntimeException("Cannot stringify the input json node", e);
          }
      }
docs: Converts a JsonNode to its string representation.
  This implementation use a `pretty printer`.
  
  @param json the json node
  @return the String representation of the given Json Object
  @throws java.lang.RuntimeException if the String form cannot be created