Find QR code in image and decode it using Zxing

I now read deeper into Zxing and the following code will work with Zxing v3.2.1 (This code works without javase lib)

// Imports
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.RGBLuminanceSource;
import com.google.zxing.Reader;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;

// Interesting method
public static String decodeQRImage(String path) {
    Bitmap bMap = BitmapFactory.decodeFile(path);
    String decoded = null;

    int[] intArray = new int[bMap.getWidth() * bMap.getHeight()];
    bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(),
            bMap.getHeight());
    LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(),
            bMap.getHeight(), intArray);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

    Reader reader = new QRCodeReader();
    try {
        Result result = reader.decode(bitmap);
        decoded = result.getText();
    } catch (NotFoundException e) {
        e.printStackTrace();
    } catch (ChecksumException e) {
        e.printStackTrace();
    } catch (FormatException e) {
        e.printStackTrace();
    }
    return decoded;
}

This code works fine for me. Hope it helps just import the necessary packages and it should work

public class QR_Reader extends JFrame implements Runnable, ThreadFactory {

private static final long serialVersionUID = 6441489157408381878L;

private Executor executor = Executors.newSingleThreadExecutor(this);

private Webcam webcam = null;
private WebcamPanel panel = null;
String s;

public QR_Reader() {
    super();
    setLayout(new FlowLayout());
    setTitle("Reading QR Code");
    Dimension size = WebcamResolution.QVGA.getSize();
    webcam = Webcam.getWebcams().get(0);
    webcam.setViewSize(size);
    panel = new WebcamPanel(webcam);
    panel.setPreferredSize(size);
    add(panel);
    pack();
    setVisible(true);
    setResizable(false);
    executor.execute(this);
}
@Override
public void run() {

    do {
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Result result = null;
        BufferedImage image = null;

        if (webcam.isOpen()) {

            if ((image = webcam.getImage()) == null) {
                continue;
            }

            LuminanceSource source = new BufferedImageLuminanceSource(image);
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

            try {
                result = new MultiFormatReader().decode(bitmap);
            } catch (NotFoundException e) {
                // fall thru, it means there is no QR code in image
            }
        }

        if (result != null) {
            String time_then=result.getText();  //this is the text extracted from QR CODE
            webcam.close();
            this.setVisible(false);
            this.dispose();
            try {
                new Compare().C_Main(time_then);
            } catch (ParseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    } while (true);
}

@Override
public Thread newThread(Runnable r) {
    Thread t = new Thread(r, "example-runner");
    t.setDaemon(true);
    return t;
}

void QRC_Main() {
    new QR_Reader();
}
}

here is the code to create the Qr-Code and read Message from Qr-code

1. you need the build the zxing library

2. main describe the qr-code creation and qr-code extraction

   package com.attendance.mark;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileNotFoundException;
   import java.io.IOException;
   import java.util.HashMap;
   import java.util.Map;
   
   import javax.imageio.ImageIO;
   
   import com.google.zxing.BarcodeFormat;
   import com.google.zxing.BinaryBitmap;
   import com.google.zxing.EncodeHintType;
   import com.google.zxing.MultiFormatReader;
   import com.google.zxing.MultiFormatWriter;
   import com.google.zxing.NotFoundException;
   import com.google.zxing.Result;
   import com.google.zxing.WriterException;
   import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
   import com.google.zxing.client.j2se.MatrixToImageWriter;
   import com.google.zxing.common.BitMatrix;
   import com.google.zxing.common.HybridBinarizer;
   import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
   
   public class QRCode {
   
       /**
        * 
        * @param args 
        * @throws WriterException
        * @throws IOException
        * @throws NotFoundException
        */
     public static void main(String[] args) throws WriterException, IOException,
         NotFoundException {
       String qrCodeData = "student3232_2015_12_15_10_29_46_123";
       String filePath = "F:\\Opulent_ProjectsDirectory_2015-2016\\.metadata\\.plugins\\org.eclipse.wst.server.core\\tmp0\\wtpwebapps\\AttendanceUsingQRCode\\QRCodes\\student3232_2015_12_15_10_29_46_123";
       String charset = "UTF-8"; // or "ISO-8859-1"
       Map<EncodeHintType, ErrorCorrectionLevel> hintMap = new HashMap<EncodeHintType, ErrorCorrectionLevel>();
       hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
   
       createQRCode(qrCodeData, filePath, charset, hintMap, 200, 200);
       System.out.println("QR Code image created successfully!");
   
       System.out.println("Data read from QR Code: "
           + readQRCode(filePath, charset, hintMap));
   
     }
   
     /***
      * 
      * @param qrCodeData
      * @param filePath
      * @param charset
      * @param hintMap
      * @param qrCodeheight
      * @param qrCodewidth
      * @throws WriterException
      * @throws IOException
      */
     public static void createQRCode(String qrCodeData, String filePath,
         String charset, Map hintMap, int qrCodeheight, int qrCodewidth)
         throws WriterException, IOException {
       BitMatrix matrix = new MultiFormatWriter().encode(
           new String(qrCodeData.getBytes(charset), charset),
           BarcodeFormat.QR_CODE, qrCodewidth, qrCodeheight);
       MatrixToImageWriter.writeToFile(matrix, filePath.substring(filePath
           .lastIndexOf('.') + 1), new File(filePath));
     }
   
     /**
      * 
      * @param filePath
      * @param charset
      * @param hintMap
      * 
      * @return Qr Code value 
      * 
      * @throws FileNotFoundException
      * @throws IOException
      * @throws NotFoundException
      */
     public static String readQRCode(String filePath, String charset, Map hintMap)
         throws FileNotFoundException, IOException, NotFoundException {
       BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(
           new BufferedImageLuminanceSource(
               ImageIO.read(new FileInputStream(filePath)))));
       Result qrCodeResult = new MultiFormatReader().decode(binaryBitmap, hintMap);
       return qrCodeResult.getText();
     }
   }