docs: public Object getObject(Integer key, Object newValue, JSONConverter converter) {
          if (newValue == null && key == Integer.MIN_VALUE) {
              return null;
          }
  
          Object previousValue = objectLibrary.get(key);
  
          if (previousValue == null) {
  
              if (newValue == null) {
                  throw ErrorHelper.createRESTHandlerJsonException(new ListenerNotFoundException("Could not match Filter and Handback objects"),
                                                                   converter,
                                                                   APIConstants.STATUS_BAD_REQUEST);
              }
  
              previousValue = objectLibrary.putIfAbsent(key, newValue);
  
              if (previousValue == null) {
                  previousValue = newValue;
              }
          }
  
          return previousValue;
      }