java.net.SocketException: Socket is closed while socket is still open

Question

So I'm trying to receive a message from my server when there comes a notification from Google Cloud Messaging (GCM). My code is the following:

public class GcmIntentService extends IntentService {
 //This class is executed by the BradcastReceiver when the devices
 //gets a message from GCM
    public static final int NOTIFICATION_ID = 1;
    private NotificationManager notificationManager;
    NotificationCompat.Builder builder;

    public GcmIntentService() {
        super("GcmIntentService");
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Bundle extras = intent.getExtras();
        GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
        String messageType = gcm.getMessageType();

        if (!extras.isEmpty()) {
            if (GoogleCloudMessaging.MESSAGE_TYPE_MESSAGE.equals(messageType)) {
                Log.i("INTENTSERVICE", extras.toString());
                sendNotification(extras);
            }
            Log.e("WAKELOCK","Wakelock will end");
            GcmBroadcastReceiver.completeWakefulIntent(intent);
        }
    }

    private void sendNotification(final Bundle extras){
                Socket socket = null;
                FileOutputStream fileStream;
                MessageSet ms = null;
                try {

                    socket = new Socket(getString(R.string.server_address), 37133);
                    Tools.sendDataToServer(getApplicationContext(), 
                        socket, 
                        MessageTypes.PULLMESSAGE, 
                        extras.getString("content")); //sending does perfectly work

                    //Receive contents of Message
                    DataInputStream dis = 
                        new DataInputStream(socket.getInputStream()); // but now is doesn't 
                                                  //want to do more and the exception is thrown
                    byte type = dis.readByte();
                    /* doing things */ 
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    //Tools.close(socket);
                }

                /* post notification */
    }
}

I can create the Socket and send Data to the server, wich is also received, but when I want to receive data on the phone afterwards, it gives an java.net.SocketException: Socket is closed Exception. But at the same time, the server is still sending data and the socket on the phone is also still open (according to debugger [PIC]).

But why does this Error occur?

The requested code of Tools.sendDataToServer

public static void sendDataToServer(Context context, Socket socket, int messageType, String content){
        try {
            SharedPreferences prefs = context.getSharedPreferences(context.getString(R.string.SharedPrefs),0);
            OutputStream out = socket.getOutputStream();

            out.write(messageType);
            byte[] msgBytes = (prefs.getString("userID","") + "|;" + prefs.getString("userSession","") + "|;" + content).getBytes("UTF-8");
            Tools.writeDataLengthToStream(out, msgBytes.length);
            out.write(msgBytes,0,msgBytes.length);
            out.flush();
            //out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

When out.close() is commented out, it is working. Thats a problem I already had, but I still don't have a clue why it is like this.

what does the Tools.sendDataToServer do? Can you post that code? — eldjon
– eldjon, Commented Jul 26, 2014 at 17:59
@eldjon : thats the code, it works without the out.close() line. — schnaidar
– schnaidar, Commented Jul 27, 2014 at 17:15

user207421 · Accepted Answer · 2014-07-26 18:46:16Z

1

The Socket is closed. You closed it, in this application. The peer may still be trying to send data but it will get a 'connection reset' exception.

answered Jul 26, 2014 at 18:46

user207421

312k45 gold badges324 silver badges493 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

schnaidar Over a year ago

yeah, it was the problem, that after closing the outputStream, the socket will be closed, too. But I still don't know why, as the documentation doesn't really says anything about it.

Dennis · Accepted Answer · 2014-07-26 19:32:32Z

0

At least you have to close the Socket connection instance inside finally. Test if it is null, if you don't do that a reference may persist in memory. And also make sure that it is not executing in the main thread. After that if the same error persist, try to reinstall the application to clean up the memory cache.

And also avoid close the Socket instance inside the Tool Class.

answered Jul 26, 2014 at 19:32

Dennis

11 bronze badge

2 Comments

user207421 Over a year ago

Testing for null doesn't prevent instances from persisting in memory.

schnaidar Over a year ago

The Tools.close() is just a "shortcut" for if ! Null then close . Is this not a good practice?

Collectives™ on Stack Overflow

java.net.SocketException: Socket is closed while socket is still open

2 Answers 2

1 Comment

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related