@Override
    public void visitClass(@NotNull PsiClass aClass) {
      // no call to super, so that it doesn't drill down to inner classes
      if (!UtilityClassUtil.isUtilityClass(aClass)) {
        return;
      }

      if (aClass.hasModifierProperty(PsiModifier.FINAL) ||
          aClass.hasModifierProperty(PsiModifier.ABSTRACT)) {
        return;
      }

      final Query<PsiClass> query = ClassInheritorsSearch.search(aClass, false);
      final PsiClass subclass = query.findFirst();
      if (subclass != null) {
        return;
      }

      registerClassError(aClass, aClass);
    }
@Override
    public void visitClass(@NotNull PsiClass aClass)