Get the Particular Occupant from room(MUC) using android

Hello everybody, I want know how to fetch the Occupant from MUC room. I try something like below i mentioned but that is not use. I can’t able to fetch it. I supposed , i did something wrong. i don’t know what it is. Anyone help me…?

MultiUserChat muc = getMucManager() .getMultiUserChat("xxxx@conference.xxx");

Occupant occupant = muc .getOccupant("xxxxxx@xxxx");