rashemihmih

public class Country {
    private String name;
    private int sum;
    private HashSet<Integer> users = new HashSet<>();

    public Country(Record record) {
        name = record.getCountry();
        sum = record.getCount();
        users.add(record.getId());
    }

rashemihmih

import java.io.*;

public class Main {
    public static void main(String[] args) {
        A a = new A(4);
        try (OutputStream os = new FileOutputStream("a");
             ObjectOutputStream oos = new ObjectOutputStream(os)) {
            oos.writeObject(a);
            os.write("hello".getBytes());
        } catch (IOException e) {