import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

class Student {

int rollno;

String name;

int age;

Student(int rollno, String name, int age) {

this.rollno = rollno;

this.name = name;

this.age = age;

}

}

class AgeComparator implements Comparator<Student> {

public int compare(Student s1, Student s2) {

if (s1.age == s2.age) {

return 0;

} else if (s1.age > s2.age) {

return 1;

} else {

return -1;

}

}

}

class NameComparator implements Comparator<Student> {

public int compare(Student s1, Student s2) {

return s1.name.compareTo(s2.name);

}

}

public class TestComparator {

public static void main(String[] args) {

List<Student> list = new ArrayList<Student>();

list.add(new Student(101, "Sharad", 23));

list.add(new Student(106, "Devashree", 27));

list.add(new Student(105, "Dutta", 21));

Collections.sort(list, new AgeComparator());

for (Student stu : list) {

System.out.println(stu.rollno + " " + stu.name + " " + stu.age);

}

Collections.sort(list, new NameComparator());

for (Student stu : list) {

System.out.println(stu.rollno + " " + stu.name + " " + stu.age);

}

}

}