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Java Socket - hanging on socket creation

I have an Android device (client) and Ubuntu 16.04 machine (server). I'm trying to establish a socket connection to send messages to and from each.

I had it working earlier on port 6943, now it hangs somewhere. I am unsure how to proceed in debugging this, no exceptions or errors occur. It simply hangs up on Socket s = new Socket("192.168.0.216", 6943) (client), because the line Log.d(TAG, "Creating I/O streams"); no longer runs.

6943

Socket s = new Socket("192.168.0.216", 6943)

Log.d(TAG, "Creating I/O streams");

Note: "xxx.xxx.x.xxx" is the IP address of my Ubuntu machine.

"xxx.xxx.x.xxx"

Client-side code:

public class SocketManager {

public static String TAG = "SocketManagerClass";

public static void createSocket() {
try {

Scanner scn = new Scanner(System.in);

Log.d(TAG, "Creating new socket object");
Socket s = new Socket("xxx.xxx.x.xxx", 6943);

Log.d(TAG, "Creating I/O streams");
DataInputStream dis = new DataInputStream(s.getInputStream());
DataOutputStream dos = new DataOutputStream(s.getOutputStream());

while (true) {
Log.d(TAG, dis.readUTF());
String toSend = scn.nextLine();
dos.writeUTF(toSend);

if (toSend.equals("Exit")) {
Log.d(TAG, "Closing this connection");
s.close();
break;
}

String received = dis.readUTF();
Log.d(TAG, received);
}

scn.close();
dis.close();
dos.close();
} catch (Exception e) {
Log.e(TAG, "exception", e);
}
}
}


The client-side code is initiated inside MainActivity like so:

MainActivity

public class ConnectSocket extends AsyncTask<Void, Void, Void> {
public Void doInBackground(Void... params) {
// Create instance of the socket manager class then execute its' function
try {
Log.d("ConnectSocket", "Creating instance and running func");
socketManager.createSocket();
} catch (Exception e) {
Log.e(TAG, "exception", e);
}
return null;
}
}


Then ran inside the onCreate method of the MainActivity as follows:

onCreate

MainActivity

ConnectSocket connectSocket = new ConnectSocket();
connectSocket.execute();


Server-side code (I am simply running this from the command line after compiling):

import java.net.*;
import java.util.*;
import java.text.*;
import java.io.*;

public class SocketServer {

public static void main(String args) throws Exception {
ServerSocket serverSocket = new ServerSocket(6943);
System.out.println("Creating socket server...");

while (true) {
Socket socket = null;

try {
socket = serverSocket.accept();
System.out.println("New socket accepted: " + socket);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}


I can see the System.out.println("Creating socket server..."); line in the terminal.

System.out.println("Creating socket server...");

It must be an issue with the port 6943. netstat -l | grep 6943 returns nothing, and port 6943 isn't in sight when I use netstat -l. Did this port vanish into thin air? What is going on here?

6943

netstat -l | grep 6943

6943

netstat -l

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