请教java问题 - Java / Java相关

代码如下：abstract class Person{
  private String name;
  private char sex;
  private int age;
  Person(String n,int a,char s){
  name=n;
  age=a;
  sex=s;
  }
  public String getName(){
  return name;
  }
  public int getAge(){
  return age;
  }
  public char getSex(){
  return sex;
  }
}
class Student extends Person{
  private String id;
  private double score;
  Student(String n,String i,int a,char s,double sr){
  super(n,a,s);
  id=i;score=sr;
  }
  public String getId(){
  return id;  
  } 
  public double getScore(){
  return score;
  }
  public void display(){
  System.out.println("我的个人信息：");
  System.out.println("姓名："+this.getName());
  System.out.println("学号："+this.getId());
  System.out.println("年龄："+this.getAge());
  System.out.println("性别："+this.getSex());
  System.out.println("成绩："+this.getScore());
  }
}
class tes