code: public void addAll(State otherState) {
      Properties diffCommonProps = new Properties();
      diffCommonProps.putAll(Maps.difference(this.commonProperties, otherState.commonProperties).entriesOnlyOnRight());
      addAll(diffCommonProps);
      addAll(otherState.specProperties);
    }
docs: Populates this instance with properties of the other instance.
  
  @param otherState the other {@link State} instance