求帮助，编译时不报错。运行时报错。

Question

package n;public interface Comparable<Student> {   public int compareTo(Student s);}package n;import java.util.Set;import java.util.TreeSet;public class Student implements Comparable<Student> {       int id;       String name;       public Student(int id, String name){           this.id = id;           this.name = name;       }       public int compareTo(Student s){           if(this.id < s.id) return -1;           else if(this.id > s.id) return 1;           else return 0;       }       public String toString(){           return "<" + this.id + "." + this.name + ">";       }    public static void main(String[] args) {        // TODO 自动生成的方法存根        Student[] stud = new Student[]{                new Student(1002, "张三"),                new Student(1003, "李四"),                new Student(1001, "王五")        };        Set<Student> ts = new TreeSet<Student>();        for(int i = 0; i < stud.length; i ++)            ts.add(stud[i]);            System.out.println(ts);    }   }

Answer 1

报什么错？