code: public JsonNode readTree(String postData) throws JsonParseException, JsonMappingException, IOException {
          return (objectMapper.readTree(postData));
      }
docs: Reads and parses the String containing JSON data and returns a JsonNode tree representation.
  
  @param postData a String holding the POST data
  @return a JsonNode instance containing the parsed JSON
  @throws JsonParseException when an error occurs parsing the provided JSON
  @throws JsonMappingException if a JSON error occurs
  @throws IOException if an error occurs reading the JSON data