Getting IOException with HttpURLConnection.setChunkedStreamingMode() - http

Question

I've written HttpUrlConnection wrapper. It supports file uploading, so I'm using HttpUrlConnection.setChunkedStreamingMode() to prevent OutOfMemoryException.
But after writing all data to OutputStream I getting IOException. Without this method everything works fine.
Here the code:
HttpURLConnection connection = getConnection();
if(!isSent) {
OutputStream output;
if(!files.isEmpty()) {
connection.setRequestProperty(HEADER_CONTENT_TYPE, CONTENT_TYPE_MULTIPART);
// Tried to add this line, but still not working
connection.setRequestProperty("Transfer-Encoding","chunked");
connection.setChunkedStreamingMode(chunkSize);
output = new BufferedOutputStream(connection.getOutputStream());
writeParamsMultipart(output);
writeFilesMultipart(output);
output.write((PREFIX + BOUNDARY + PREFIX + LINEND).getBytes());
} else {
connection.setRequestProperty(HEADER_CONTENT_TYPE, CONTENT_TYPE_FORM);
output = new BufferedOutputStream(connection.getOutputStream());
output.write(paramsToUrlencoded(post).getBytes());
}
output.flush();
output.close();
isSent = true;
}
// Getting exception on this line
InputStream input = new BufferedInputStream(connection.getInputStream());
if(ENCODING_GZIP.equalsIgnoreCase(connection.getHeaderField(HEADER_CONTENT_ENCODING))) {
input = new GZIPInputStream(input);
}
return input;
chunkSize by default 1024 bytes. What's the problem?

Answer 1

It's FileNotFoundException
That means that the URL is incorrect. It's the equivalent of HTTP 403.
Nothing to do with chunked transfer mode.