Concurrency Example from Bazlur Sir's Book

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.util.concurrent.TimeUnit;

public class TwoFileDownloadingWithJoin {
    public static void main(String[] args) {
        Thread beatPrinter = new BeatPrinter();
        Thread down1 = new FileDownloader("https://goo.gl/nqZJn4", "meet1.jpg");
        Thread down2 = new FileDownloader("https://goo.gl/UoSMMt", "meet2.jpg");
        beatPrinter.setName("Beat Printer");
        down1.setName("file1 downloader");
        down2.setName("file2 downloader");

        try {
            down1.start();
            down2.start();
            TimeUnit.MILLISECONDS.sleep(100);
            beatPrinter.start();

            down1.join();
            down2.join();
            ((BeatPrinter) beatPrinter).kill();
            beatPrinter.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Download Complete");
    }
}

class BeatPrinter extends Thread {

    private volatile boolean live = true;

    @Override
    public void run() {
        while (live) {
            printStar("Downloading ");
        }
    }

    void kill() {
        live = false;
    }

    private void printStar(String msg) {
        System.out.print(msg);
        char[] signs = {'-', '\\', '|', '/'};
        for (char s : signs) {
            System.out.print(s);
            try {
                Thread.sleep(300);
                System.out.print('\b');
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        for (int i = 0; i < msg.length(); i++)
            System.out.print('\b');
    }
}

class FileDownloader extends Thread {
    private String url;
    private String fileName;

    FileDownloader(String url, String fileName) {
        this.url = url;
        this.fileName = fileName;
    }

    @Override
    public void run() {
        File destinationFile = new File(fileName);
        try {
            System.out.println("Starting download of " + fileName);
            URL fileUrl = new URL(url);

            HttpURLConnection connection = (HttpURLConnection) fileUrl.openConnection();
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                InputStream inputStream = connection.getInputStream();
                Files.copy(inputStream, destinationFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
                inputStream.close();
            } else {
                System.out.println("Error: " + connection.getResponseMessage());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}