Use of natural sorting comparable

package com.it;

public class Student implements Comparable<Student>{
    private String name;
    private int age;

    public Student() {
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public int compareTo(Student o) {
      //  return 1;// positive sequence 
     //   return -1;   Descending 
     //   int num = this.age - o.age; // Ascending 
       int num = o.age-this.age; // Descending 
  //      return num;
// When the age is the same , Than name , In alphabetical order 
        int num2 = num == 0 ? this.name.compareTo(o.name) : num;

        return num2;
    }
}

 

package com.it;

import java.util.TreeSet;

public class TreeSetDemo {
    public static void main(String[] args) {
        TreeSet<Student> ts = new TreeSet<>();

        Student s1 = new Student(" Huluwa ", 23);
        Student s2 = new Student(" Peter Jackson's King Kong ", 22);
        Student s3 = new Student(" monkey ", 24);
        Student s4 = new Student(" Dog ",24);

        ts.add(s1);
        ts.add(s2);
        ts.add(s3);
        ts.add(s4);

        // Traverse 
        for (Student s : ts) {
            System.out.println(s.getName() + "," + s.getAge());

        }

    }
}