Getting all the users from openfire server using smack in android

i have a openfire server running on my localhost and i am successfully able to send and receive messages to registered users. however i am not been able to get all users from server. i am logged in with user that doesn't have a administration access. so do i need to give any permission on server side?

The code i am using for getting all users is..

if( xmpp.getConnection()==null||!xmpp.getConnection().isConnected())
   return;

   try{
   UserSearchManager usm =newUserSearchManager(xmpp.getConnection());
   Form searchForm = usm.getSearchForm("search."+ xmpp.getConnection().getServiceName());
   Form answerForm = searchForm.createAnswerForm();
   UserSearch userSearch =newUserSearch();
  answerForm.setAnswer("Username",true);
  answerForm.setAnswer("search", userName);
   ReportedData data = userSearch.sendSearchForm(xmpp.getConnection(), answerForm,"search."+ xmpp.getConnection().getServiceName());

   for(ReportedData.Row row : data.getRows())
   {
  arrayList.add(row.getValues("Username").toString());
   }
   }catch(Exception e){
  e.printStackTrace();
   }

i tried some solutions that shows to use Roster class, however that is also not helping me. Can anyone show what i am doing wrong or if i need to give any permission as i am not logged in as admin?

Thanks