How to add new users in the chat room?

I tried this code but not working can anybody help?

public void invitationReceived(XMPPConnection connection, String room,String inviter,

String reason, String password, Message arg5) {

// TODO Auto-generated method stub

MultiUserChat m = new MultiUserChat(connection, room);

try

{

                            m.join("akn@IISD", password);

}

catch (XMPPException ex)

{

}

}