code: @Override
      public JsonNode visit(JmesPathField fieldNode, JsonNode input) {
          if (input.isObject()) {
              //TODO : CamelCase will need to change at some point
              return input.get(CamelCaseUtils.toCamelCase(fieldNode.getValue()));
          }
          return NullNode.getInstance();
      }
docs: Retrieves the value of the field node
  
  @param fieldNode JmesPath field type
  @param input     Input json node whose value is
  retrieved
  @return Value of the input json node