How to sort an ArrayList?

Question

I have a List of doubles in java and I want to sort ArrayList in descending order.

Input ArrayList is as below:

List testList = new Arr         


        

Answer 1

If you have to sort object based on its id in the ArrayList , then use java8 stream.

 List personList = new ArrayList<>();

    List personListSorted =
                personList.stream()
                  .sorted(Comparator.comparing(Person::getPersonId))
                  .collect(Collectors.toList());