How to sort an ArrayList?
Collections.sort(testList);Collections.reverse(testList);That will do what you want. Remember to import Collections though!
Descending:
Collections.sort(mArrayList, new Comparator<CustomData>() { @Override public int compare(CustomData lhs, CustomData rhs) { // -1 - less than, 1 - greater than, 0 - equal, all inversed for descending return lhs.customInt > rhs.customInt ? -1 : (lhs.customInt < rhs.customInt) ? 1 : 0; }});
For your example, this will do the magic in Java 8
List<Double> testList = new ArrayList();testList.sort(Comparator.naturalOrder());But if you want to sort by some of the fields of the object you are sorting, you can do it easily by:
testList.sort(Comparator.comparing(ClassName::getFieldName));or
testList.sort(Comparator.comparing(ClassName::getFieldName).reversed());or
testList.stream().sorted(Comparator.comparing(ClassName::getFieldName).reversed()).collect(Collectors.toList());Sources: https://docs.oracle.com/javase/8/docs/api/java/util/Comparator.html