这不挺简单的吗

1.实现不难，比较基础

2.样例

Student.java

public abstract class Student {
    // 学号,set,get
    private int num;
    // 姓名,set,get
    private String name;
    // 班级状态,set,get
    private int classStatus;

    // 注册
    public abstract boolean register();

    // 注销
    public abstract boolean logout();
}

CollegeStudent.java 本科生

//本科生
public class CollegeStudent extends Student{

    @Override
    public boolean register() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean logout() {
        // TODO Auto-generated method stub
        return false;
    }
    
}

GraduateStudent.java,研究生

//研究生
public class GraduateStudent extends Student {

    @Override
    public boolean register() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean logout() {
        // TODO Auto-generated method stub
        return false;
    }

}