Vaadin 8 Upload Component Not Working for me

Basically I have been using Vaadin Designer to design my UI. One of my use cases asks me to upload an iCalendar file, I use a grammar (ANTLR) to get from it what I need. I came across my issue when after seeing the Vaadin Upload documentation and aplying it to my use case when running it, nothing would happen and no expection would be thrown. After a bit of research and debugging I belive this is due to the Thread for the upload being shutdown for some reason.

Here is my code, any help?

private void uploadLogic() {

class IcalendarUploader implements Upload.Receiver, Upload.SucceededListener, Upload.FinishedListener, Upload.FailedListener {

@Override public OutputStream receiveUpload(String filename, String mimeType) {
try {
//We'll store the uploadad file as temporary file.
tempFile = File.createTempFile("temp", ".ics");
return new FileOutputStream(tempFile);
} catch (IOException e) {
Notification.show(e.getMessage(), Notification.Type.WARNING_MESSAGE); return null;
} catch (Exception e){
Notification.show(e.getMessage(), Notification.Type.WARNING_MESSAGE); return null;
} }

@Override public void uploadFinished(Upload.FinishedEvent event) {
try {
controller.importIcalendar(tempFile);
tempFile.delete();
Notification.show("Uploaded iCalendar file with :\n" + controller.iCalendarDetails(), Notification.Type.HUMANIZED_MESSAGE);
} catch (IOException e) {
Notification.show(e.getMessage(), Notification.Type.WARNING_MESSAGE); } }

@Override public void uploadSucceeded(Upload.SucceededEvent event) {
try {
if(controller.saveTimeSlot()){
Notification.show("Uploaded iCalendar file with :\n" + controller.iCalendarDetails() +"\nSaved time slot with success", Notification.Type.HUMANIZED_MESSAGE);
}else {
Notification.show("Uploaded iCalendar file with :\n" + controller.iCalendarDetails() + "\nTime slot has an overlapp!", Notification.Type.WARNING_MESSAGE); }
} catch (DataConcurrencyException e) {
Notification.show(e.getMessage(), Notification.Type.WARNING_MESSAGE);
} catch (DataIntegrityViolationException e) {
Notification.show(e.getMessage(), Notification.Type.WARNING_MESSAGE); } }

@Override public void uploadFailed(Upload.FailedEvent event) {
Notification.show("Upload failed", Notification.Type.ERROR_MESSAGE); } }

IcalendarUploader receiver = new IcalendarUploader();
upload.setReceiver(receiver);

Hi,
You mention that coul be an issue on the thread for the upload.
Could you confirm that using the upload component you have the same problem.
I posted a question concerning upload and the problem could be the same.
Thanks for your support