How to sort a list without mutating it

Question

I would like to sort a List of items in Java and have the sort return a new sorted List without mutating the original List. Is there a commonly used library that does this?

Answer 1

If you are using Java 8 or higher, you can use the Stream API. See Sorting a list with stream.sorted() in Java for details.

For example:

List<String> sortedList = myList.stream().sorted().collect(Collectors.toList());

Answer 2

This copies (by reference) the elements in the original list to the new list. Making changes like the ordering of one list won't affect the other.

List<String> originalList = new ArrayList<String>();
List<String> newList = new ArrayList(originalList);

Please note if you modify the objects that are in the list however, the changes will be reflected in both lists since objects are copied by reference.