用Java设计一个教材类，一个课程类，及一个为某门课程指定参考教材的类。一门课程可以有多本参考教材，再设计一个测试类。

教材类：

public class Textbook {
    private String name;
    private String author;

    public Textbook(String name, String author) {
        this.name = name;
        this.author = author;
    }

    public String getName() {
        return name;
    }

    public String getAuthor() {
        return author;
    }
}

课程类：

import java.util.ArrayList;

public class Course {
    private String name;
    private ArrayList<Textbook> textbooks;

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

    public void addTextbook(Textbook textbook) {
        textbooks.add(textbook);
    }

    public ArrayList<Textbook> getTextbooks() {
        return textbooks;
    }

    public String getName() {
        return name;
    }
}

为某门课程指定参考教材的类：

public class CourseTextbook {
    private Course course;
    private Textbook textbook;

    public CourseTextbook(Course course, Textbook textbook) {
        this.course = course;
        this.textbook = textbook;
    }

    public Course getCourse() {
        return course;
    }

    public Textbook getTextbook() {
        return textbook;
    }
}

测试类：

public class Test {
    public static void main(String[] args) {
        Textbook tb1 = new Textbook("Java编程思想", "Bruce Eckel");
        Textbook tb2 = new Textbook("Effective Java", "Joshua Bloch");

        Course course = new Course("Java编程");
        course.addTextbook(tb1);
        course.addTextbook(tb2);

        CourseTextbook ct1 = new CourseTextbook(course, tb1);
        CourseTextbook ct2 = new CourseTextbook(course, tb2);

        System.out.println(ct1.getCourse().getName() + "的参考教材有：");
        for (Textbook tb : ct1.getCourse().getTextbooks()) {
            System.out.println(tb.getName() + " - " + tb.getAuthor());
        }

        System.out.println(ct2.getCourse().getName() + "的参考教材有：");
        for (Textbook tb : ct2.getCourse().getTextbooks()) {
            System.out.println(tb.getName() + " - " + tb.getAuthor());
        }
    }
}

输出：

Java编程的参考教材有：
Java编程思想 - Bruce Eckel
Effective Java - Joshua Bloch
Java编程的参考教材有：
Java编程思想 - Bruce Eckel
Effective Java - Joshua Bloch