private static int getImplementationsCount(RefOverridable refClass) {
    int count = 0;
    for (RefOverridable reference : refClass.getDerivedReferences()) {
      if (reference instanceof RefClass) {
        if (!((RefClass)reference).isInterface() && !((RefClass)reference).isAbstract()) {
          count++;
        }
        count += getImplementationsCount(reference);
      }
      else if (reference instanceof RefFunctionalExpression) {
        count++;
      }
    }

    return count;
  }
private static int getImplementationsCount(RefOverridable refClass)