为什么正常输出不了啊

Question

不添加第七行前输出学生姓名为null
添加第七行直接出错了，为啥啊

Answer 1

package text;

class Student {
    private String name;

    public void SetName(String n) {
        this.name = n;
    }

    String getName() {
        return name;
    }
}

class Undergraduate extends Student {
    private String major;

    public void SetMajor(String n, String m) {
        super.SetName(n);
        this.major = m;
    }

    public void show() {
        System.out.printf("学生姓名：" + super.getName() + "专业信息：" + major);
    }
}

public class Text {
    public static void main(String[] args) {
        Undergraduate undergraduate = new Undergraduate();
        undergraduate.SetMajor("李俊梅", "信息管理与信息系统");
        undergraduate.show();
    }
}