code: public void put(String keyName, Class<?> arrayComponentType, Object value) {
      ArrayValueMap.ArrayValue arrayValue = keyMap.get(keyName);
      if (arrayValue == null) {
        arrayValue = new ArrayValue(arrayComponentType);
        keyMap.put(keyName, arrayValue);
      }
      arrayValue.addValue(arrayComponentType, value);
    }
docs: Puts an additional value for the given key name, accumulating values on repeated calls on the
  same key name.
  
  @param keyName key name
  @param arrayComponentType array component type
  @param value value