code: public List<Ticket> checkTickets(Set<String> tickets) throws FlickrException {
          Map<String, Object> parameters = new HashMap<String, Object>();
          parameters.put("method", METHOD_CHECK_TICKETS);
  
          StringBuffer sb = new StringBuffer();
          Iterator<String> it = tickets.iterator();
          while (it.hasNext()) {
              if (sb.length() > 0) {
                  sb.append(",");
              }
              Object obj = it.next();
              if (obj instanceof Ticket) {
                  sb.append(((Ticket) obj).getTicketId());
              } else {
                  sb.append(obj);
              }
          }
          parameters.put("tickets", sb.toString());
  
          Response response = transportAPI.post(transportAPI.getPath(), parameters, apiKey, sharedSecret);
          if (response.isError()) {
              throw new FlickrException(response.getErrorCode(), response.getErrorMessage());
          }
  
          // <uploader>
          // <ticket id="128" complete="1" photoid="2995" />
          // <ticket id="129" complete="0" />
          // <ticket id="130" complete="2" />
          // <ticket id="131" invalid="1" />
          // </uploader>
  
          List<Ticket> list = new ArrayList<Ticket>();
          Element uploaderElement = response.getPayload();
          NodeList ticketNodes = uploaderElement.getElementsByTagName("ticket");
          int n = ticketNodes.getLength();
          for (int i = 0; i < n; i++) {
              Element ticketElement = (Element) ticketNodes.item(i);
              String id = ticketElement.getAttribute("id");
              String complete = ticketElement.getAttribute("complete");
              boolean invalid = "1".equals(ticketElement.getAttribute("invalid"));
              String photoId = ticketElement.getAttribute("photoid");
              Ticket info = new Ticket();
              info.setTicketId(id);
              info.setInvalid(invalid);
              info.setStatus(Integer.parseInt(complete));
              info.setPhotoId(photoId);
              list.add(info);
          }
          return list;
      }
docs: Checks the status of one or more asynchronous photo upload tickets. This method does not require authentication.
  
  @param tickets
  a set of ticket ids (Strings) or {@link Ticket} objects containing ids
  @return a list of {@link Ticket} objects.
  @throws FlickrException