ThreadJoinExample.java

package thread;

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

class DownloadingHeartBeat extends Thread {
    private volatile boolean beating = true;

    @Override
    public void run() {
        String[] dots = {
                ".",
                "..",
                "...",
                "...."
        };
        while (beating) {
            for (String dot : dots) {
                System.out.print("\r" + dot);
                try {
                    Thread.sleep(50);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public void shutdown() {
        this.beating = false;
    }
}


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

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

    @Override
    public void run() {
        try {
            System.out.println("Started to download '" + fileName + "'");
            URL resourceToDownload = new URL(url);
            URLConnection connection = resourceToDownload.openConnection();
            InputStream input = connection.getInputStream();

            File fileToSave = new File(fileName);
            Files.copy(input, fileToSave.toPath(), StandardCopyOption.REPLACE_EXISTING);
            input.close();
        } catch (IOException e) {
            System.err.println("Couldn't download the file: " + e.getMessage());
        }
    }
}

public class ThreadJoinExample {
    public static void main(String[] args) throws InterruptedException {
        FileDownloader downloader1
                = new FileDownloader("https://secure.meetupstatic.com/photos/event/e/9/f/9/600_464039897.jpeg", "jugbd-meetup7_1.jpeg");
        FileDownloader downloader2
                = new FileDownloader("https://secure.meetupstatic.com/photos/event/2/d/0/f/600_464651535.jpeg", "jugbd-meetup7_2.jpeg");

        DownloadingHeartBeat heartBeat = new DownloadingHeartBeat();

        downloader1.start();
        downloader2.start();
        heartBeat.start();

        try {
            downloader1.join();
            downloader2.join();

            //both threads are done, lets shutdown the heartbeat 
            heartBeat.shutdown();

            // lets wait for stopping the heartbeat thread
            heartBeat.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("\nThe download is complete");
    }
}