watermark over image using java

public class WaterMarking {
    public static  void main(String ar[]){
        File sourceImageFile = new File("D:/WaterMarking/input.jpg");
        File destImageFile = new File("D:/WaterMarking/output.jpg");//created automatically
        WaterMarking waterMarking=new WaterMarking();
        waterMarking.addTextOverImage("java", sourceImageFile, destImageFile);
    }
    void addTextOverImage(String text, File sourceImageFile, File destImageFile) {
    try {
        BufferedImage sourceImage = ImageIO.read(sourceImageFile);
        Graphics2D g2d = (Graphics2D) sourceImage.getGraphics();

     
        AlphaComposite alphaChannel = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.1f);
        g2d.setComposite(alphaChannel);
        g2d.setColor(Color.BLUE);
        g2d.setFont(new Font("Arial", Font.BOLD, 64));
        FontMetrics fontMetrics = g2d.getFontMetrics();
        Rectangle2D rect = fontMetrics.getStringBounds(text, g2d);

     
        int centerX = (sourceImage.getWidth() - (int) rect.getWidth()) / 2;
        int centerY = sourceImage.getHeight() / 2;

   
        g2d.drawString(text, centerX, centerY);

        ImageIO.write(sourceImage, "png", destImageFile);

        g2d.dispose();
   

    } catch (IOException ex) {
        System.err.println(ex);
    }
}
}