@CheckForNull
    protected T computeNext() {
      while (!stack.isEmpty()) {
        PostOrderNode<T> top = stack.getLast();
        if (top.childIterator.hasNext()) {
          T child = top.childIterator.next();
          stack.addLast(expand(child));
        } else {
          stack.removeLast();
          return top.root;
        }
      }
      return endOfData();
    }

severely as to bring tears into her eyes; and once she remembered
trying to box her own ears for having cheated herself in a game
of croquet she was playing against herself, for this curious
child was very fond of pretending to be two people.  `But it's no
use now,' thought poor Alice, `to pretend to be two people!  Why,
there's hardly enough of me left to make ONE respectable
person!'

      }
      if (systemLoader != null) {
        try {
          return systemLoader.loadClass(FINALIZER_CLASS_NAME);
        } catch (ClassNotFoundException e) {
          // Ignore. Finalizer is simply in a child class loader.
          return null;
        }
      } else {
        return null;
      }
    }
  }

  /**

      }
      if (systemLoader != null) {
        try {
          return systemLoader.loadClass(FINALIZER_CLASS_NAME);
        } catch (ClassNotFoundException e) {
          // Ignore. Finalizer is simply in a child class loader.
          return null;
        }
      } else {
        return null;
      }
    }
  }

  /**