code: public String toJson() {
          logger.entering();
  
          parseResults();
  
          Gson gson = new GsonBuilder().setPrettyPrinting().create();
          String json = gson.toJson(this);
          logger.exiting(json);
          return json;
      }
docs: This method generate the JSON string for the instance. GSON builder helps to build JSON string and it will
  exclude the static and transient variable during generation.
  
  @return JSON string