学生选课）根据下面的类图，编写课程Course类和学生Student类。并用题目给出的测试类Test进行测试。不允许改动题目提供的测试类Test代码。Course类说明如下：（1）addStudent()方法用于添加一个选课的学生；（2）dropStudent()方法用于删除一个选课的学生；（3）toStrin()g方法用于返回课程的所有信息，包括课程名称和选课学生。Student类说明如下：（1）toString()方法用于返回学生的信息。（2）equals()方法用于判断两个学生是否为同一个学生。注意equals()方法的参数类型。

根据上述要求，可以编写如下的Course类和Student类：

Course类：

import java.util.ArrayList;
import java.util.List;

public class Course {
    private String name;
    private List<Student> students;

    public Course(String name) {
        this.name = name;
        this.students = new ArrayList<>();
    }

    public String getName() {
        return name;
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public void dropStudent(Student student) {
        students.remove(student);
    }

    public List<Student> getStudents() {
        return students;
    }

    @Override
    public String toString() {
        return "Course{" +
                "name='" + name + '\'' +
                ", students=" + students +
                '}';
    }
}

Student类：

public class Student {
    private String name;
    private int id;

    public Student(String name, int id) {
        this.name = name;
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public int getId() {
        return id;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", id=" + id +
                '}';
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Student)) {
            return false;
        }
        Student other = (Student) obj;
        return this.id == other.id;
    }
}

测试类Test：

public class Test {
    public static void main(String[] args) {
        Course math = new Course("Math");

        Student alice = new Student("Alice", 1);
        Student bob = new Student("Bob", 2);
        Student charlie = new Student("Charlie", 3);

        math.addStudent(alice);
        math.addStudent(bob);
        math.addStudent(charlie);

        System.out.println(math);
        // Output: Course{name='Math', students=[Student{name='Alice', id=1}, Student{name='Bob', id=2}, Student{name='Charlie', id=3}]}

        math.dropStudent(bob);

        System.out.println(math);
        // Output: Course{name='Math', students=[Student{name='Alice', id=1}, Student{name='Charlie', id=3}]}
    }
}