Code from appium-read-qrcode

DecodeQRCode.java

private static String decodeQRCode(BufferedImage qrCodeImage) {
    Result result = null;
    try {
        LuminanceSource source = new BufferedImageLuminanceSource(qrCodeImage);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

        result = new MultiFormatReader().decode(bitmap);
    } catch (NotFoundException e) {
        log.error("QRCode not found", e);
    }
    return result.getText();
}

The complete code can be found at https://github.com/eliasnogueira/appium-read-qrcode