} catch (MyException expected) {
    }
  }

  private static Iterator<Integer> newDoubler(int first, final int last) {
    return new AbstractSequentialIterator<Integer>(first) {
      @Override
      protected @Nullable Integer computeNext(Integer previous) {
        return (previous == last) ? null : previous * 2;
      }
    };
  }

    } catch (MyException expected) {
    }
  }

  private static Iterator<Integer> newDoubler(int first, final int last) {
    return new AbstractSequentialIterator<Integer>(first) {
      @Override
      protected @Nullable Integer computeNext(Integer previous) {
        return (previous == last) ? null : previous * 2;
      }
    };
  }