questions about multiuserchat

Hi everyone,

I have some questions on using multiuserchat which confuse me a whloe night.

1)

I know the basic mehod to create a chat room.

MultiUserChat muc=new MultiUserChat( connectin , groupaddress)
muc.join(nickname)
muc.addMessageListener(......)

The documents says it will create a multi user chat. But if the groupaddress is an existed group, will I join the group or create a new one?

http://www.igniterealtime.org/builds/smack/docs/3.4.0/javadoc/org/jivesoftware/s mackx/muc/MultiUserChat.html#MultiUserChat(org.jivesoftware.smack.Connection, java.lang.String)

2)

if I run the code above twice, what will happen?

MultiUserChat muc=new MultiUserChat( connectin , groupaddress)
muc.join(nickname)
muc.addMessageListener(......)
muc=new MultiUserChat( connectin , groupaddress)
muc.join(nickname)
muc.addMessageListener(......)

I think the messasgelistener is a thread. Are the both threads running now or only the latest one?

3)

How can I join more than one rooms and addmessagelistener?

Thank you all.

Strong Su