An exception is thrown in PacketOutputStream.sendStream (see attached stacktrace for details)! The implementation of sendStream is faulty (line 169):

while ((len = reader.read(buffer, 0, (int) readLength)) > 0)

In my case, readLength == 36214! You cannot read more data than the buffer size and hence the exception (here reader is a StringReader)! The readLength parameter of reader.read should be replaced by something like that:

reader.read(buffer, 0, buffer.length)