<dependency>
  <groupId>com.google.zxing</groupId>
  <artifactId>core</artifactId>
  <version>3.3.0</version>
</dependency>
<dependency>
  <groupId>com.google.zxing</groupId>
  <artifactId>javase</artifactId>
  <version>3.3.0</version>
</dependency>

public void encode(String content, String filepath) throws WriterException, IOException {
  int width = 100;
  int height = 100;
  Map<EncodeHintType, Object> encodeHints = new HashMap<EncodeHintType, Object>();
  encodeHints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
  BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, encodeHints);
  Path path = FileSystems.getDefault().getPath(filepath);
  MatrixToImageWriter.writeToPath(bitMatrix, "png", path);
} 

public String decode(String filepath) throws IOException, NotFoundException {
  BufferedImage bufferedImage = ImageIO.read(new FileInputStream(filepath));
  LuminanceSource source = new BufferedImageLuminanceSource(bufferedImage);
  Binarizer binarizer = new HybridBinarizer(source);
  BinaryBitmap bitmap = new BinaryBitmap(binarizer);
  HashMap<DecodeHintType, Object> decodeHints = new HashMap<DecodeHintType, Object>();
  decodeHints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
  Result result = new MultiFormatReader().decode(bitmap, decodeHints);
  return result.getText();
}