public Date getEmptyDate() {
        return this.emptyDate;
    }
Returns the date when the last occupant left the room. A null value means that there are
occupants in the room at the moment.

@return the date when the last occupant left the room or null if there are occupants in the
        room at the moment.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCRoom.java