Exam 클래스

public class Exam {
	private String examName;
	private int kor;
	private int eng;
	private int mat;
	public Exam(String examName) {
		this.examName = examName;
	}
	public void setScore() {
		kor = (int)(Math.random() * 101);
		eng = (int)(Math.random() * 101);
		mat = (int)(Math.random() * 101);
	}
	public void examInfo() {
		System.out.println(examName + "성적");
		System.out.println("국어:" + kor + ", 영어:" + eng + ", 수학" + mat);
		int total = kor + eng + mat;
		System.out.println("총점:" + total + ", 평균:" + (total / 3.0));
	}

Student 클래스

public class Student {
	private String name;
	private Exam exam;
	public Student(String name) {
		this.name = name;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Exam getExam() {
		return exam;
	}
	public void setExam(Exam exam) {
		this.exam = exam;
	}
	public void info() {
		System.out.println("학생명:" + name);
		exam.examInfo();
	}

Main 클래스

public class Main {
	public static void main(String[] args) {
		Exam exam = new Exam("중간고사");
		exam.setScore();  // 국, 영, 수학 점수 0 ~ 100 사이 랜덤 생성
		Student student = new Student("emily");
		student.setExam(exam);
		student.info();
	}
}

출력

학생명:emily
중간고사성적
국어:31, 영어:82, 수학11
총점:124, 평균:41.333333333333336