JAVA程序问题 难以解决，求帮助

https://zhidao.baidu.com/question/1995050878942425707.html

public class Course {
    String courseName;
    int courseHour;
 
    public Course() {
        super();
    }
 
    public Course(String courseName, int courseHour) {
        super();
        this.courseName = courseName;
        this.courseHour = courseHour;
    }
 
    public String getCourseName() {
        return courseName;
    }
 
    public void setCourseName(String courseName) {
        this.courseName = courseName;
    }
 
    public int getCourseHour() {
        return courseHour;
    }
 
    public void setCourseHour(int courseHour) {
        this.courseHour = courseHour;
    }
 
}

public class Course {
    private String cno;
    private String cname;
    private int score;

    public Course(String cno, String cname, int score) {
        this.cno = cno;
        this.cname = cname;
        this.score = score;
    }

    @Override
    public String toString() {
        return "Course{" +
                "cno='" + cno + '\'' +
                ", cname='" + cname + '\'' +
                ", score=" + score +
                '}';
    }
}

public class Course {
    private int nmb;//编号
    private String name;
    private int xf; //学分
    
    public Course(int id,String name,int xf){
        this.nmb = id;
        this.name = name;
        this.xf = xf;
    }
    
    public int getNmb() {
        return nmb;
    }

    public void setNmb(int nmb) {
        this.nmb = nmb;
    }

    public String getName() {
        return name;
    }

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

    public int getXf() {
        return xf;
    }

    public void setXf(int xf) {
        this.xf = xf;
    }

    

    

    @Override
    public String toString() {
        return "Course [nmb=" + nmb + ", name=" + name + ", xf=" + xf + "]";
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Course cs = new Course(100,"物理",3);
        System.out.println(cs.toString());
    }
}

看看java基础