java对象数组排序

import java.util.Arrays;
class ArrayTest
{
public static void main(String[] args)
{

Student[] ss=new Student[]{new Student(1,"zhangsan"),
   new Student(2,"lisi"),
   new Student(3,"wangwu"),
   new Student(3,"mybole")};
Arrays.sort(ss);
for(int i=0;i<ss.length;i++)
{
System.out.println(ss[i]);
}
int index=Arrays.binarySearch(ss,new Student(2,"lisi"));
System.out.println("index="+index);
System.out.println(ss[index]);
}
}
class Student implements Comparable
{
int num;
String name;
Student(int num,String name)
{
this.num=num;
this.name=name;
}
public String toString()
{
return "number="+num+","+"name="+name;
}
public int compareTo(Object o)
{
Student s=(Student)o;
int result=num>s.num ? 1 : (num==s.num ? 0 : -1);
if(0==result)
{
result=name.compareTo(s.name);
}
return result;
}
}用Eclipse运行通过不了，请高手帮忙解决！！！