Servlet call hanging when using S3 Java SDK - gwt

Question

I have this servlet I call using GWT FileUpload (I don't thing it matters so much that it is GWT):
#Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
try {
User user = ServerUtil.validateUser(request);
ServletFileUpload upload = new ServletFileUpload();
try {
FileItemIterator iter = upload.getItemIterator(request);
while (iter.hasNext()) {
FileItemStream item = iter.next();
String saveFile = item.getName();
InputStream stream = item.openStream();
// Process the input stream
ByteArrayOutputStream out = new ByteArrayOutputStream();
int len;
byte[] buffer = new byte[8192];
while ((len = stream.read(buffer, 0, buffer.length)) != -1) {
out.write(buffer, 0, len);
}
int maxFileSize = 10 * (1024 * 1024); //10 megs max
if (out.size() > maxFileSize) {
throw new RuntimeException("File is > than " + maxFileSize);
}
// save file data
String fileName = user.getUsername() + "_" + new Date().getTime() + "_" + saveFile;
// store to S3
String imageUrl = S3PhotoUtil.storeThumbnailImage(out.toByteArray(), fileName, 100);
// return the url of the file
writer.println(imageUrl);
response.flushBuffer();
return;
}
} catch (RuntimeException e) {
writer.println(("error=" + e.getMessage()).getBytes());
} catch (FileUploadException e) {
writer.println(("error=Could not read file").getBytes());
} catch(IOException e) {
writer.println(("error=Image type not supported!").getBytes());
}
} catch (EIException e) {
e.printStackTrace();
writer.println(("error=Not logged in").getBytes());
}
}
When called the POST hangs, I check on firebug, it looks like it never gets a response. If I debug I see that all instructions are executed without any problem and the method is ran fine. The files are stored on my S3 bucket.
Now if I remove the call relating to the S3 storage it stops hanging, although obviously it doesn't do anything anymore... My conclusion is that there is something in this S3 storage that messes up with my servlet. The code itself is taken from the travel log example application # http://aws.amazon.com/code/1264287584622066
It does say needs tomcat and I'm using jetty... could that be a problem?
Thanks,
Thomas