Untitled

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class ExamGrader {
    static class ExamAnswer {
        public int question;
        public String answer;
    }

    static class Exam {
        public String id;
        public String name;
        public String type;
        public List<ExamAnswer> answers;
    }

    static class Student {
        public String id;
        public String name;
        public String surname;
        public Exam exam;
    }

    static class ExamResult {
        public Student student;
        public int score;
    }

    public static void main(String[] args) {
        if (args.length < 2) {
            System.out.println("Usage: java ExamGrader exam_folder answer_key");
            System.exit(1);
        }

        String examFolder = args[0];
        String answerKeyFile = args[1];

        ObjectMapper objectMapper = new ObjectMapper();

        // Read answer key
        Exam answerKey = null;
        try {
            answerKey = objectMapper.readValue(new File(answerKeyFile), Exam.class);
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }

        // Read student answers
        List<Student> students = new ArrayList<>();
        File folder = new File(examFolder);
        File[] listOfFiles = folder.listFiles();
        for (File file : listOfFiles) {
            if (file.isFile()) {
                try {
                    Student student = objectMapper.readValue(file, Student.class);
                    students.add(student);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        // Grade exams
        List<ExamResult> results = new ArrayList<>();
        for (Student student : students) {
            ExamResult result = new ExamResult();
            result.student = student;
            int score = 0;
            for (int i = 0; i < student.exam.answers.size(); i++) {
                ExamAnswer studentAnswer = student.exam.answers.get(i);
                ExamAnswer correctAnswer = answerKey.answers.get(i);
                if (studentAnswer.answer.equals(correctAnswer.answer)) {