Java Comparator

package Object_Oriented;


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




public class Test {

    public static void main(String[] args) {
        ArrayList student_list = new ArrayList<>();
        List list = new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        Collections.sort(list, new Comparator() {
            @Override
            public int compare(Integer o1, Integer o2) {
                return o1 - o2;
            }
        });
    }

}