private static byte[] readAllBytes(PushbackInputStream inputStream)
                            throws IOException

According to the Java API "An attempt is made to read as many as len bytes, but a smaller number may be read". [http://docs.oracle.com/javase/7/docs/api/java/io/InputStream.html#read(byte[],%20int,%20int)] For this reason we need to ensure that we've read all the bytes that we need out of this stream.