コンパレータを使用して Java でカスタム オブジェクトのリストを正しく並べ替えるにはどうすればよいですか?

import java.util.Comparator;

public class PeopleComparator implements Comparator<People> {

    @Override
    public int compare(People p1, People p2) {
        return p1.getId() - p2.getId();
    }
}

import java.util.ArrayList;
import java.util.Collections;

public class TestPeople {

    public static void main(String[] args) {
        ArrayList<People> peps = new ArrayList<>();

        peps.add(new People(123, "M", 14.25));
        // ...

        Collections.sort(peps, new PeopleComparator());

        for (People person : peps) {
            System.out.println(person);
        }
    }
}

Collections.sort(peps, new Comparator<People>() {

    @Override
    public int compare(People p1, People p2) {
        return p1.getId() - p2.getId();
    }
});

Collections.sort(peps, (p1, p2) -> p1.getId() - p2.getId());