How to create XMPP chat client for facebook?

to get access token first you have to login

fb.authorize(FacebookActivity.this, new String[] {"xmpp_login"},Facebook.FORCE_DIALOG_AUTH, new DialogListner());

SASLXFacebookPlatformMecha class

import java.io.IOException;
import java.net.URLEncoder;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;

import org.apache.harmony.javax.security.auth.callback.CallbackHandler;
import org.apache.harmony.javax.security.sasl.Sasl;
import org.jivesoftware.smack.SASLAuthentication;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.sasl.SASLMechanism;
import org.jivesoftware.smack.util.Base64;

public class SASLXFacebookPlatformMecha extends SASLMechanism {

private static final String NAME = "X-FACEBOOK-PLATFORM";

private String apiKey = "";
private String access_token = "";

/**
 * Constructor.
 */
public SASLXFacebookPlatformMecha(SASLAuthentication saslAuthentication) {
    super(saslAuthentication);
}

@Override
protected void authenticate() throws IOException, XMPPException {

    getSASLAuthentication().send(new AuthMechanism(NAME, ""));
}

@Override
public void authenticate(String apiKey, String host, String acces_token)
        throws IOException, XMPPException {
    if (apiKey == null || acces_token == null) {
        throw new IllegalArgumentException("Invalid parameters");
    }

    this.access_token = acces_token;
    this.apiKey = apiKey;
    this.hostname = host;

    String[] mechanisms = { NAME };
    Map<String, String> props = new HashMap<String, String>();
    this.sc = Sasl.createSaslClient(mechanisms, null, "xmpp", host, props,
            this);
    authenticate();
}

@Override
public void authenticate(String username, String host, CallbackHandler cbh)
        throws IOException, XMPPException {
    String[] mechanisms = { NAME };
    Map<String, String> props = new HashMap<String, String>();
    this.sc = Sasl.createSaslClient(mechanisms, null, "xmpp", host, props,
            cbh);
    authenticate();
}

@Override
protected String getName() {
    return NAME;
}

@Override
public void challengeReceived(String challenge) throws IOException {
    byte[] response = null;

    if (challenge != null) {
        String decodedChallenge = new String(Base64.decode(challenge));
        Map<String, String> parameters = getQueryMap(decodedChallenge);

        String version = "1.0";
        String nonce = parameters.get("nonce");
        String method = parameters.get("method");

        long callId = new GregorianCalendar().getTimeInMillis();

        String composedResponse = "api_key="
                + URLEncoder.encode(apiKey, "utf-8") + "&call_id=" + callId
                + "&method=" + URLEncoder.encode(method, "utf-8")
                + "&nonce=" + URLEncoder.encode(nonce, "utf-8")
                + "&access_token="
                + URLEncoder.encode(access_token, "utf-8") + "&v="
                + URLEncoder.encode(version, "utf-8");

        response = composedResponse.getBytes("utf-8");
    }

    String authenticationText = "";

    if (response != null) {
        authenticationText = Base64.encodeBytes(response,
                Base64.DONT_BREAK_LINES);
    }

    // Send the authentication to the server
    getSASLAuthentication().send(new Response(authenticationText));
}

private Map<String, String> getQueryMap(String query) {
    Map<String, String> map = new HashMap<String, String>();
    String[] params = query.split("\\&");

    for (String param : params) {
        String[] fields = param.split("=", 2);
        map.put(fields[0], (fields.length > 1 ? fields[1] : null));
    }

    return map;
}
}

I created ChatManager class

import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManagerListener;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.MessageListener;
import org.jivesoftware.smack.Roster;
import org.jivesoftware.smack.RosterListener;
import org.jivesoftware.smack.SASLAuthentication;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.packet.Presence;
import org.jivesoftware.smack.packet.Presence.Type;
import org.jivesoftware.smackx.pubsub.PresenceState;

public class FacebookChatManager {

private static FacebookChatManager chatManager;
private XMPPConnection connection;
private final String SERVER = "chat.facebook.com";
private final int PORT = 5222;
private final String FACEBOOK_MECHANISM = "X-FACEBOOK-PLATFORM";
private RosterListener rosterListner;

private FacebookChatManager(RosterListener rosterListner)
{
    this.rosterListner = rosterListner;
    ConnectionConfiguration connFig = new ConnectionConfiguration(SERVER,
            PORT);
    connFig.setSASLAuthenticationEnabled(true);
    connection = new XMPPConnection(connFig);
    //setup facebook authentication mechanism
    SASLAuthentication.registerSASLMechanism(FACEBOOK_MECHANISM,
            SASLXFacebookPlatformMecha.class);
    SASLAuthentication.supportSASLMechanism(FACEBOOK_MECHANISM, 0);
}

public static FacebookChatManager getInstance(RosterListener rosterListner)
{
    if(chatManager == null)
    {
        chatManager =  new FacebookChatManager(rosterListner);
    }
    return chatManager;
}

public boolean connect()
{
    try {
        connection.connect();
        return true;
    } catch (XMPPException e) {
        e.printStackTrace();
        connection.disconnect();
    }
    return false;
}

public void disConnect()
{
    connection.disconnect();
}

public boolean logIn(String apiKey, String accessToken)
{
    try {
        connection.login(apiKey, accessToken);
        setPresenceState(Presence.Type.available, "");
        connection.getRoster().addRosterListener(rosterListner);
        return true;
    } catch (XMPPException e) {
        connection.disconnect();
        e.printStackTrace();
    }
    return false;
}

public Roster getRoster()
{
    return connection.getRoster();
}

public Chat createNewChat(String user, MessageListener messageListner)
{
    return connection.getChatManager().createChat(user, messageListner);
}

public void registerNewIncomingChatListner(ChatManagerListener chatManagerListner)
{
    connection.getChatManager().addChatListener(chatManagerListner);
}

public void setPresenceState(Type precenseType, String status)
{
    Presence presence = new Presence(precenseType);
    presence.setStatus(status);
    connection.sendPacket(presence);
}

public Presence getUserPresence(String userId)
{
    return connection.getRoster().getPresence(userId);
}
}

at the end to use that FacebookChatManager class note that rosterListnr is used to get info about your friends state change implement one as you want

FacebookChatManager facebookChatManager = FacebookChatManager.getInstance(rosterListner);

if (facebookChatManager.connect()) {
            if (facebookChatManager.logIn(FacebookActivity.APP_ID,
                    access_token)) {
                return facebookChatManager.getRoster();
            }
        }