我是Java双非初学者，这道实验题运行不出来

Question

代码如下:class Student {
public int studentid;
public String name;
public int birthday;
public String department;
public String girlfriend;

public void getInfo() {
    System.out.println("studentid+name+birthday+department+girlfriend");
}

}

class Undergraduate extends Student {
    public String counsler;

    public void getInfo() {
        System.out.println("counsler");
    }
}

class Graduate extends Student {
    public String supervisor;

    public void getInfo() {
        System.out.println("supervisor");
    }
}

class test {

    void main() {

        {
            Undergraduate Zhong = new Undergraduate();
            Zhong.name = "小明";
            Zhong.birthday = 2002201;
            Zhong.studentid = 55;
            Zhong.department = "信息学院";
            Zhong.girlfriend = "小红";
            Zhong.counsler = "琳琳";
            Zhong.getInfo();
        }
    }
}

题目和运行结果在这

我调到心灰意冷了😭