How to count duplicate elements in ArrayList?

Question

I need to separate and count how many values in arraylist are the same and print them according to the number of occurrences.

I\'ve got an arraylist called digits :<

Answer 1

Well, for that you can try to use Map

Map countMap = new HashMap<>();

  for (Integer item: yourArrayList) {

      if (countMap.containsKey(item))
          countMap.put(item, countMap.get(item) + 1);
      else
          countMap.put(item, 1);
  }

After end of forEach loop you will have a filled map with your items against it count