Implementing an xmpp client in java - stuck in the first step

Question

I am trying to write an xmpp client to send/recieve messages from gtalk.

Before I actually started with the implementation I thought of developing a prototype to see if I am able to to get a message through to gtalk.

I wrote the following code and am now stuck in the part where I am supposed to request google before starting an encrypted connection.

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class XmppConnect {
static String initiate_conn="<?xml version=\"1.0\"?>\n\r<stream:stream to=\"google.com\"\n\rversion=\"1.0\"\n\rxmlns=\"jabber:client\"\n\rxmlns:stream=\"http://etherx.jabber.org/streams\">\n";
static String start_tls="<starttls xmlns=\"urn:ietf:params:xml:ns:xmpp-tls\"/>";
public static void main(String [] args)
    {
        try {
            Socket connection = new Socket("talk.google.com", 5222);
            DataInputStream input = new DataInputStream(connection.getInputStream());
            BufferedReader d = new BufferedReader(new InputStreamReader(input));
            OutputStream to_server = null;
            String responseLine;
            to_server = connection.getOutputStream();
            to_server.write(initiate_conn.getBytes());
            responseLine = d.readLine();       
            System.out.println("Server: " + responseLine);
            to_server.write(start_tls.getBytes());
            responseLine = d.readLine();       
            System.out.println("Server: " + responseLine);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

I am able to send the following to google

<starttls xmlns="urn:ietf:params:xml:ns:xmpp-tls"/>

and in reply I expect the following

<proceed xmlns="urn:ietf:params:xml:ns:xmpp-tls"/>

But I don't get anything back from the server.

The screenshot from wireshark is as attached.

Request your help and please don't tell me to use already existing xmpp libraries cause I just don't want to.

Regards, Manu!

Update

Have found the solution. The working code is as under:

The code which works for now is as under.

Now I will work on the TLS implementation and get back here incase of any doubts :) :)

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class XmppConnect {
static String initiate_conn="<stream:stream to=\"gmail.com\" version=\"1.0\" xmlns=\"jabber:client\" xmlns:stream=\"http://etherx.jabber.org/streams\">";
static String start_tls="<starttls xmlns=\"urn:ietf:params:xml:ns:xmpp-tls\"/>";
public static void main(String [] args)
    {
        try {
            Socket connection = new Socket("talk.google.com", 5222);
            DataInputStream input = new DataInputStream(connection.getInputStream());
            BufferedReader d = new BufferedReader(new InputStreamReader(input,"UTF-8"));
            BufferedWriter to_server = new BufferedWriter(
                    new OutputStreamWriter(connection.getOutputStream(),"UTF-8")
                    );
            String responseLine="";
            to_server.write(initiate_conn);
            to_server.flush();
            int in;
            while(!(responseLine.contains("</stream:features>")))
            {
                responseLine += (char)d.read();   
            }
            System.out.println("Server: " + responseLine);
            to_server.write(start_tls);
            to_server.flush();
            responseLine="";
            while(!(responseLine.contains("<proceed xmlns=\"urn:ietf:params:xml:ns:xmpp-tls\"/>")))
                responseLine += (char)d.read();   
            System.out.println("Server: " + responseLine);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

Check the SMACK which provides a nice XMPP stack for Java. It's well documented and easy to use.

Answer 2

Perhaps this will help you:

XMPP IM Client

Don't be so quick to dismiss existing libraries. You can learn from them and then implement your own if you desire. You want to reinvent the wheel without looking at a wheel, using other people to describe a wheel to you.