public Features applySet(final FeatureSet featureSet){
  final Set<Feature> features=new HashSet<>(this.features);
  features.addAll(featureSet.getEnabled());
  features.removeAll(featureSet.getDisabled());
  return new Features(features);
}

public Features applySet ( final FeatureSet featureSet ) { final Set < Feature > features = new HashSet < > ( this . features ) ; features . addAll ( featureSet . getEnabled ( ) ) ; features . removeAll ( featureSet . getDisabled ( ) ) ; return new Features ( features ) ; }
apply the given feature set .
