Android - HttpUrlConnection is not closing. Eventually results to SocketException

Question

I am encountering some problems with the HttpUrlConnection in devices running Jellybean (4.1 - 4.3) wherein connections are not closed and results to a SocketException "Too many open files" after executing a number of times.

I do call HttpUrlConnection.disconnect() and am closing all the Inputstream, Outputstream, Reader and Writers in a finally block.

Going to adb shell and executing a netstat shows all the connections created by the application are left in CLOSE_WAIT state.

InputStream inputStream = httpUrlConnection.getInputStream();

// After calling inputStream.read() then the problem occurs. I think the 
// inputstream doesn't get closed even after calling close in a finally block. 
// The InputStream is a ChunkedInputStream if that helps.

I have tried other devices running on 2.3.3, 4.0.3 and 4.4 and did not encounter this issue.

Is there another way that I can manually close the connections?

I had the same problem but it was isolated to the Android **Emulator**. When trying on a real device, it did not show these issues. Not saying that will helps others, but I tried everything to fix the issue on the Emulator and then I just tried on a real device, and it wasn't an issue. The Emulator was running Android 6 and the real device was on Android 9, btw. — Joshua Pinter, Aug 21 '19 at 19:20
Coming back here to reply to my own comment. We eventually did see this on the real device as well, but only under circumstances where a bunch of a download URLs were not valid and not returning actual content. So something is for sure still leaking and causing too many open files. — Joshua Pinter, Oct 03 '19 at 15:16

score 15 · Accepted Answer · answered Dec 06 '13 at 06:33

15

I finally found a workaround. It seems that Jellybean is having an issue on "Keep-Alive" connections. I just added Connection=Close to my request header and now all is working. Doing a netstat, I see that the connections are now being closed and I no longer get the SocketException due to "Too many open files".

answered Dec 06 '13 at 06:33

Mark Pazon

6,167
2
34
50

1

How did you add this to the request header? Could you post the code? – Tim T Jan 14 '14 at 21:11
7

@TimT `connection.setRequestProperty("Connection","Close");` – Mark Pazon Jan 17 '14 at 01:52
1

@mussharapp life saver, been looking at this for days. Thanks! – Bundeeteddee Aug 05 '14 at 10:21
Excellent! I've been chasing this for a whole week. – grebulon Mar 10 '16 at 13:27
‍♂️Saved my day. – sagarkothari Apr 12 '21 at 13:57

score 1 · Answer 2 · answered Dec 04 '13 at 07:08

Check If you have tried all of the below... There might be something missing.. other wise it should not have any problem.

InputStream in;
HttpsURLConnection urlConnection =null;
try {
    URL url = new URL(Url);

    urlConnection = (HttpsURLConnection) url
                     .openConnection();
    //5 Second timeout
    urlConnection.setReadTimeout(5*1000);

    in = urlConnection.getInputStream();
    int responseCode = urlConnection.getResponseCode();

    if (responseCode != HttpURLConnection.HTTP_OK) {
         InputStream errInputStream = urlConnection.getErrorStream();
        //Print error message and response code..
         errInputStream.close();
    }
    in.close();
} catch (Exception e) {
    e.printStackTrace();
} finally{
    if(urlConnection != null)
        urlConnection.disconnect();
}

Thanks for your answer. I am already doing this but still doesnt fix the issue on devices running Jellybean. — Mark Pazon, Dec 04 '13 at 07:21

score 0 · Answer 3 · answered Dec 04 '13 at 06:16

0

You might be better off not calling disconnect() and thus allowing it to do HTTP connection pooling.

answered Dec 04 '13 at 06:16

user207421

305,947
44
307
483

Thanks for your quick response. I tried this but I am still having the problem – Mark Pazon Dec 04 '13 at 06:45
I would examine your statement that everything gets closed in finally blocks. There's a leak somewhere. – user207421 Dec 04 '13 at 06:57
Yes, I have examined that everything gets closed in finally blocks. As I have mentioned, this only happens on devices (even emulators) running Jellybean. Gingerbread, ICS and Kitkat were okay. – Mark Pazon Dec 04 '13 at 07:20
So that suggests a bug in Jellybean. – user207421 Dec 04 '13 at 22:31

score 0 · Answer 4 · answered Oct 05 '19 at 15:08

Try using OkHttp Instead.

Once you get the Maven dependency added, you can do something like the following to download a file:

OkHttpClient okHttpClient = new OkHttpClient.Builder().build();

OutputStream output = null;

try {
  Request request   = new Request.Builder().url( download_url ).build();
  Response response = okHttpClient.newCall( request ).execute();

  if ( !response.isSuccessful() ) {
    throw new FileNotFoundException();
  }

  output = new FileOutputStream( output_path );

  output.write( response.body().bytes() );
}
finally {
  // Ensure streams are closed, even if there's an exception.
  if ( output != null ) output.flush();
  if ( output != null ) output.close();
}

Switching to OkHttp instantly fixed our leaked file descriptor issue so it's worth trying if you're stuck, even at the expense of adding another library dependency.

Android - HttpUrlConnection is not closing. Eventually results to SocketException

4 Answers4

Try using OkHttp Instead.

Linked