A participant has fewer privileges than a moderator, although he or she always has the right to speak.
A visitor is a more restricted role within the context of a moderated room, since visitors are not allowed to send messages to all occupants.
Usage In order to modify the room's subject just send change Subject(String subject) to the // An occupant wants to be notified every time the room's subject is changed muc3Subject Updated Listener(new Subject Updated Listener() ); // A room's owner changes the room's subject muc2.change Subject("New Subject"); These roles are temporary in that they do not persist across a user's visits to the room and can change during the course of an occupant's visit to the room.
A moderator is the most powerful occupant within the context of the room, and can to some extent manage other occupants' roles in the room.
Every time the room's subject is changed you may want to be notified of the modification.