Problem downloading images in multi-threaded mode?

Question

Java

Hello.
I have the following problem:
Through requests to ajax.googleapis.com/ajax/services/search/ I get json responses and from the received urls I create new streams with an image loader:

for(final GoogleResponseData responseData : googleResponse.getResults()) {
////
  new Thread() {
    @Override
    public void run() {
      try {
        new ImageDownloader().downloadImage(responseData.getUrl(), path, fileName);
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }.start();
////
}

loader code:

private void downloadImage(String imageUrl, String path, fileName) throws IOException {
  URL u = new URL(imageUrl);
  
  String type = imageUrl.substring(imageUrl.lastIndexOf("."));
  
  URLConnection connection = u.openConnection();
  
  File imageFile = new File(path);
  imageFile.mkdirs();
  OutputStream os = new FileOutputStream(path  + fileName + type);
  try {
    IOUtils.copy(connection.getInputStream(), os);
  } catch(IOException e) {
    e.printStackTrace();
  } finally {
    os.close();
  }
}

As a result, most of my images are either not saved or not fully downloaded.
Although if this is done in one stream, all images are downloaded without problems.

Answer 1

Judging by the above code, everything seems to be normal, more code is needed. There is a guess that you are not correctly waiting for the completion of all threads and exit without waiting for the end of the download on all threads.

Answer 2

It is possible that most of the downloaded images are on the same host, and when your streams crowd into the server, it drops them due to some of its limits.