Comparings.java

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class Comparings {
    public static void main(String[] args) {
        List<User> list = Arrays.asList(new User("a"), new User("b"), new User(""), new User(null));
        //
        //        list.sort((l, r) -> Comparator.nullsFirst(Comparator.nullsFirst(Comparator.naturalOrder())).compare(l.name,
        //                r.name));

        System.out.println(list);

        List<User> list1 = Arrays.asList(new User("a"), new User("b"), new User(""), new User(null));

        list1.sort(Comparator.comparing(user -> user.name, Comparator.nullsFirst(Comparator.naturalOrder())));

        System.out.println(list1);
    }

    static class User {
        String name;

        public User(String name) {
            this.name = name;
        }

        @Override
        public String toString() {
            return "User [name=" + name + "]";
        }

    }
}