Уровень 20: план уровня и доп. материалы

import java.io.BufferedReader;
import java.io.PrintWriter;

public class Dog {
    public String name;
    public int age;

    public void save(PrintWriter printWriter) throws Exception {
        printWriter.println(name);
        printWriter.println(age);
        printWriter.flush();
    }

    public void load(BufferedReader bufferedReader) throws Exception {
        name = bufferedReader.readLine();
        age = Integer.parseInt(bufferedReader.readLine());
    }
}

import java.io.*;

public class Human {
    public Dog dog;

    public void save(OutputStream outputStream) throws Exception {
        PrintWriter printWriter = new PrintWriter(outputStream);

        String isDogPresent = dog != null ? "yes" : "no";
        printWriter.println(isDogPresent);
        printWriter.flush();

        if (dog != null) {
            dog.save(printWriter);
        }
    }

    public void load(InputStream inputStream) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));

        String isDogPresent = reader.readLine();
        if (isDogPresent.equals("yes")) {
            dog = new Dog();
            dog.load(reader);
        }
    }
}

import java.io.*;

public class Solution {
    public static void main(String[] args) {
        try {
            OutputStream outputStream = new FileOutputStream("file1.bin");
            InputStream inputStream = new FileInputStream("file1.bin");

            Human human = new Human();
            human.dog = new Dog();
            human.dog.name = "Dog1";
            human.dog.age = 2;

            human.save(outputStream);

            Human humanNew = new Human();
            humanNew.load(inputStream);
            System.ou