public class Student {          private String name ;     private int age;     public String getName() {         return name;     }     public void setName(String name) {         this.name = name;     }     public int getAge() {         return age;     }     public void setAge(int age) {         this.age = age;     }     public Student(String name,int age){         this.name = name;         this.age= age;     }     public String show(){         return "学生姓名:"+name+",年龄:"+age;              } } public class Undergraduate extends Student{     private String degree;          public Undergraduate(String name, int age,String degree) {         super(name, age);         this.degree = degree;         // TODO Auto-generated constructor stub     }     public String getDegree() {         return degree;     }     public void setDegree(String degree) {         this.degree = degree;     }          @Override     public String show() {         return super.show()+",学位是:"+degree;     } } public class Test {     @org.junit.Test     public void test(){         Student s = new Student("jing", 5);         System.out.println(s.show());         Undergraduate ug= new Undergraduate("chen", 1, "博士");         System.out.println(ug.show());     } }