java简单的接口程序

import java.util.Arrays;public class Grapeh {public static void main(String[] args) {     Employee[] staff=new Employee[3];     staff[0]=new Employee("heln",5003);     staff[1]=new Employee("mell",1000);     staff[2]=new Employee("kell",500);     Arrays.sort(staff);     for(Employee e:staff)     System.out.println("name="+e.getName()+",salary="+e.getSalary());}}

public class Employee implements Comparable<Employee>{private String name;private double salary;public Employee(String n ,double s){name=n;salary=s;}public String getName(){return name;}public double getSalary(){return salary;}public void raiseSalary(double byPercent){double raise=salary*byPercent/100;salary+=raise;}public int compareTo(Employee other){return Double.compare(salary, other.salary);}}