如何从一个文本文件中填写4个不同的ArrayLists？

Question

我正在编写一个带有问题和答案的简单测验，并希望针对4类问题制作4个ArrayLists。用户应该选择一个类别并从ArrayList中回答10个随机问题。 我找到了一段没有类别的ArrayList代码。我不知道如何实现4个ArrayLists并从一个文本文件中填充它们。有人可以帮帮我吗？

public class Questions {

private ArrayList<Question> questions = new ArrayList<Question>();

public Questions()  {
    try {
        File f = new File("src/main/resources/questions.txt");
        FileReader r = new FileReader(f);
        BufferedReader reader = new BufferedReader(r);
        Scanner scanner = new Scanner(reader);

        String line;
        String question = "";
        String[] alternatives = null;

        int answer = 0;

        int numberOfAlternatives = 0;
        int counter = 0;

        do {

            do {
                line = scanner.nextLine();

                if (line.contains("?")) { //stores the question
                    question = line;
                } else if(counter == 0 && line.length() == 1) { //stores the number of alternatives
                    numberOfAlternatives = Integer.valueOf(line);
                    alternatives = new String[numberOfAlternatives];
                } else if (line.contains(")")) { //stores the alternatives
                    alternatives[counter++] = line;
                } else if (Character.isDigit(line.indexOf(0)) || counter == numberOfAlternatives) { //Stores the answer
                    answer = Integer.valueOf(line);
                }

            }   while (answer == 0);

            questions.add(new Question(question, alternatives, answer));
            numberOfAlternatives = 0;
            counter = 0;
            answer = 0;

        }   while (scanner.hasNext());


        r.close();
        reader.close();
        scanner.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}


public ArrayList<Question> getQuestions()  {
    return questions;
}

}