我不知道我想做的事是否可行。我已经创建了一个2d arrayList（它可以是列表中的一个列表），我需要拉取列表中的第二个元素，然后将它们添加到一起。
希望我有所有需要帮助的代码。我是个新手，这是我任务的最后一部分，我就是想不明白。

//member variable/arrays
public static ArrayList<ArrayList<Integer>> courseGrade = new ArrayList<>();
    public static ArrayList<ArrayList<Integer>> courseGradeTotal = new ArrayList<>();
    private int countCourseEnrollment = 0;
    private int takeCode;
    private static int totalGrade1 = 0;
    private static int grade1 = 0

//method to calculate course average
public static void calculateOverallGrade() {
        Course.listCourses();

        System.out.println(" ");
        System.out.print("Enter the course code to get course average:");
        String takeCode1 = Main.scan.next();

        System.out.println("Current students in course: " + takeCode1);

        for (ArrayList<Object> currentStudent : courseEnrollment) {
            if (currentStudent.contains(takeCode1)) {
                System.out.println(currentStudent);
                int index = currentStudent.indexOf(takeCode1);
                System.out.println(index);
                for (ArrayList<Integer> currentGrade : courseGrade) {
                    int intGrade1 = currentGrade.get(index).get(1);
                    System.out.println(intGrade1);
                    grade1 = grade1 + intGrade1;
                }
                for (ArrayList<Integer> overAll : courseGradeTotal) {
                    int totGrade1 = overAll.get(index).get(1);
                    System.out.print(totGrade1);
                    totalGrade1 = totalGrade1 + totGrade1;
                }

            }
        }

        System.out.println("Student grades: " + grade1);
        System.out.println("Total grades could have earned: " + totalGrade1);


    } //ends CalculateOverAllGrade method

在此方法中，第二个.get有一个错误：Cannot resolve method 'get' in 'Integer'。Array courseGrade的输出是[4643，98]。第一个数字是课程代码，第二个数字是授予学生的分数。我希望这一切都有意义，提前感谢您的帮助。
我试过太多东西了，我不知道从哪里开始。