public class Comparable5 {
        public static void main(String[] args) {
            TreeSet ts=new TreeSet();
            ts.add(new Student1(2,"Thilan"));
            ts.add(new Student1(1,"Kamal"));
            ts.add(new Student1(3,"Nimal"));

            System.out.println(ts);
        }
    }
    class Student1 implements Comparable<Student>{
        int id;
        String name;
        public Student1(int id,String name){
           this.id=id;
                   this.name=name;
        }



        @Override
        public String toString() {
         return this.id+":"+this.name;
        }

        @Override
        public int compareTo(Student o) {
            if (o.name.equals(this.name)) {
                return -1;
            } else if(o.name.equals(this.name)){
                    return +1;
            }
            else{
                return 0;
            }
        }

    }