code: public void grantAdmin(Jid jid) throws XMPPErrorException, NoResponseException, NotConnectedException, InterruptedException {
          changeAffiliationByAdmin(jid, MUCAffiliation.admin);
      }
docs: Grants administrator privileges to another user. Room owners may grant administrator
  privileges to a member or unaffiliated user. An administrator is allowed to perform
  administrative functions such as banning users and edit moderator list.
  
  @param jid the bare XMPP user ID of the user to grant administrator privileges
  (e.g. "user@host.org").
  @throws XMPPErrorException if an error occurs granting administrator privileges to a user.
  @throws NoResponseException if there was no response from the server.
  @throws NotConnectedException
  @throws InterruptedException