GetOrganizer

private String getOrganizerMail(Appointment appointment) throws ServiceLocalException {
        EmailAddress apptOrganizer = appointment.getOrganizer();
        String organizerMail = apptOrganizer.getAddress();
        String exchangeUsername = basicService.getExchangeUsername();
        if (!organizerMail.equals(exchangeUsername)) {
            return organizerMail;
        }
        AttendeeCollection attendees = appointment.getRequiredAttendees();
        List<Attendee> attendeeList = attendees.getItems();
        Stream<Attendee> attendeeStream = attendeeList.stream();
        Optional<Attendee> organizer = attendeeStream.findFirst();
        if (organizer.isPresent()) {
            return organizer.get().getAddress();
        }
        return "";
    }