File download android server

Question

It has been days I am struggling with this problem. I want to create a local android server to let other devices download a file in LAN. So far i have created a socket server that writes a pdf file along with header on output stream, but it is not working. When url is hit on web browser almost 95% of the data is downloaded without any problem after that download fails, it shows network problem(In Google chrome).

Following is the code to create server:

class VideoStreamServer {

    public void startServer() {
        outFilePath = getActivity().getExternalFilesDir("/") + "/pdf.pdf";
        outFile = new File(outFilePath);
        Runnable videoStreamTask = new Runnable() {
            @Override
            public void run() {
                try {
                    ServerSocket socket = new ServerSocket(port);


                    System.out.println("Waiting for client to connect.");
                    while (true) {
                        Socket client = socket.accept();

                        BufferedOutputStream os = new BufferedOutputStream(client.getOutputStream());
                        FileInputStream in = new FileInputStream(outFile);
                        BufferedInputStream inFromClient = new BufferedInputStream(client.getInputStream());

                        StringBuilder sb = new StringBuilder();
                        sb.append("HTTP/1.1 200 OK\r\n");
                        sb.append("Accept-Ranges: bytes\r\n");
                        sb.append("Connection: close\r\n");
                        sb.append("Content-Length: " + in.available() + "\r\n");
                        sb.append("Content-Disposition: attachment; filename=file.pdf\r\n");
                        sb.append("Content-Type: application/pdf \r\n");
                        sb.append("\r\n");


                        byte[] data = new byte[1024];
                        int length;
                        //inFromClient.read(data);
                        //System.out.println("request from client"+getStreamData(inFromClient));
                        System.out.println("Thread Started");
                        //System.setProperty("http.keepAlive", "false");
                        os.write(sb.toString().getBytes());
                        while ((length = in.read(data)) != -1) {
                            os.write(data, 0, length);
                        }
                        os.close();
                        client.close();
                        socket.close();
                        in.close();
                        break;
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        };

        Thread streamServer = new Thread(videoStreamTask);
        streamServer.start();
    }

}

Any help would be appreciated.

EDIT1

 public String getStreamData(InputStream in) {
    StringBuffer buffer = new StringBuffer();
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));

    String line;
    try {
        while ((line = reader.readLine()) != null) {
            buffer.append(line);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    return buffer.toString();
}