Student.java

import java.util.ArrayList;

public class Student {

    long id;

    String name;

    ArrayList<Integer> grades;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public ArrayList<Integer> getGrades() {
        return grades;
    }

    public void setGrades(ArrayList<Integer> grades) {
        this.grades = grades;
    }

    public Student(long id, String name, ArrayList grade) {
        this.id = id;
        this.name = name;
        this.grades = grade;
    }

    public void addGrade(int grade) {
        grades.add(grade);
    }

    public double getAverage() {
        int sum = 0;
        for (int i = 0; i < grades.size(); i++) {
            sum += grades.get(i);
        }
        return sum / grades.size();
    }

}