bb = (bb.putInt(file_index).putShort(opcode)).order(ByteOrder.LITTLE_ENDIAN);
bb = bb.order(ByteOrder.LITTLE_ENDIAN).putInt(file_index).putShort(opcode);
    protected static byte[] createUDPDatagramHeader(int file_index, short opcode, int array_size)    {	if(array_size<header_size)	    throw new InvalidParameterException("array_size must be greater than "+header_size+": "+array_size);	ByteBuffer bb = ByteBuffer.allocate(array_size);	bb = (bb.putInt(file_index).putShort(opcode)).order(ByteOrder.LITTLE_ENDIAN);	return bb.array();    }