How can I get username of a gtalk user using XMPP with google appengine?

I am using google appengine for my gtalk agent , I want to get the username of the gtalk user how can I get it ?

for your reference, check this

XMPPService xmpp = XMPPServiceFactory.getXMPPService(开发者_StackOverflow中文版);
    //STEP 2
    Message msg = xmpp.parseMessage(req);
    JID fromJid = msg.getFromJid();

I am using the above things in the beginning .....

The JID is composed of user@domain/resource. The resource is optional, and provides more information about how the user is communicating (e.g. desktop or client app).

EDIT: See the Java JID class