sorting - How can I sort a list of maps by value of some specific key using Java 8?

Question

How can I sort a List of Map<String, String> using Java 8? The map contains a key called last_name, and the value associated with it may be null. I'm not sure how to do it because the following results in a compiler error:

List<Map<String, String>> peopleList = ...

peopleList.sort(Comparator.comparing(Map::get, Comparator.nullsLast(Comparator.naturalOrder())));

Is using an anonymous class the only way to do it?

Note that I am not trying to sort each map in the list. I want to sort the list itself based on a key in each map.

Answer 1

It looks like you can rewrite your code like

peopleList.sort(Comparator.comparing(
                    m -> m.get("yourKey"), 
                    Comparator.nullsLast(Comparator.naturalOrder()))
               )