ArrayList<ArrayList<Integer>> wordIndex = new ArrayList<ArrayList<Integer>>(Collections.<ArrayList<Integer>>nCopies(initWord.length(), null));
// Populate it.
Iterator<ArrayList<Integer>> iterWordIndex = new Iterator<ArrayList<Integer>>();
Why can't I do this?
Cannot instantiate the type Iterator<ArrayList<Integer>>
You cannot instantiate an Iterator because Iterator is an interface. You can only instantiate concrete classes. In this case, let the ArrayList generate one for you:
Iterator<ArrayList<Integer>> iterWordIndex = wordIndex.iterator();
Because Iterator is an interface. You can't create an instance of it. You need to create an instance of a concrete class that implements that interface (but most of the time, you just get a reference from an existing collection).
