带有匿名内部类的Java比较器接口NullsLast

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<String> names = new ArrayList<>();
        names.add("John");
        names.add(null);
        names.add("Alice");
        names.add("Bob");

        Comparator<String> nullsLastComparator = new Comparator<String>() {
            @Override
            public int compare(String s1, String s2) {
                if (s1 == null && s2 == null) {
                    return 0;
                } else if (s1 == null) {
                    return 1;
                } else if (s2 == null) {
                    return -1;
                } else {
                    return s1.compareTo(s2);
                }
            }
        }.nullsLast();

        Collections.sort(names, nullsLastComparator);

        for (String name : names) {
            System.out.println(name);
        }
    }
}