> > > What does a browser send when it uses that form? > > I was checking that right a moment ago. I used Live Http Headers with Firefox. It seemed that it was sending one empty copy of file[] before the normal file[].
So, right before FileBody bin = new FileBody(fileToUpload); reqEntity.addPart("file[]", bin); I added: reqEntity.addPart("file[]", new ByteArrayBody(new byte[0], "")); // mimics empty request and you wouldn't believe - it works flawlessly!!! So - I hereby close this issue forever. Though I will have a couple of sleepless night why it is doing so or why is it working.... but I don't care as long as it works :P