python socket server and java android socket - freezes app

Question

I'm making a python server running on my computer and java socket client running on my phone. the minute the java tries to connect, the app freezes. Not saying anything in the logcat. I have no idea why...

python 3.5.1:

PORT = 8888

import socket

sock = socket.socket()
sock.bind(("0.0.0.0", PORT))
sock.listen(1)
client = None
while not client:
    try:
        client = sock.accept()
    except:
        pass
print(client[1])

java:

static String get_leaderboard() {
        Socket sock;
        OutputStream out;
        InputStream in;
        try {
            System.out.println("now trying to connect");
            sock = new Socket("192.168.1.29", 8888);
            System.out.println("connected successfuly");
            out = sock.getOutputStream();
            in = sock.getInputStream();
            return Integer.toString(in.read());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "Error in connection";

but actually, logcat never prints "connected successfuly". just "trying to connect".

Answer 1

This line is wrong:

client = sock.connect()

Servers don't call connect() . Servers call listen() and accept() . Only clients call connect() .

Since your server calls bind() and listen() , but not accept() , any client will hang trying to connect to it.

Resources:

• https://wiki.python.org/moin/TcpCommunication
• https://docs.python.org/3/howto/sockets.html
• http://beej.us/guide/bgnet/