How I can use a mat image

public void loadImage() {
        
		
	        
	        try {
	        	File OrignalImage = new File("c:\\images\\2.jpg");
	        	img = ImageIO.read(OrignalImage);
	           
	        } catch (Exception e) {
	            
	        }
	 
	}
	    

	 public void createBufferedImages() {
	        bufferedimageSrc = new BufferedImage(img.getWidth(this),img.getHeight(this),BufferedImage.TYPE_INT_RGB);
	       

	       bufferedimg = bufferedimageSrc.createGraphics();
	       bufferedimg.drawImage(img, 0, 0, this);

	       bufferedimageDest = new BufferedImage(bufferedimageSrc.getWidth(this),bufferedimageSrc.getHeight(this),BufferedImage.TYPE_INT_RGB);
	        bufferedimage = bufferedimageSrc;
	    }

public void greyimage() {
    	
    	
        
    	
    	
		  
    	

    	if(gray) {
    	
    		
    		
    		Imgproc.cvtColor(src, dst, Imgproc.COLOR_RGB2GRAY);

What I have tried:

i used Method to covert the buffered to mat but still its not working the distnation image on the graphics 

public void update(Graphics g) {
        g.clearRect(0, 0, getWidth(), getHeight());
        paintComponent(g);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2D = (Graphics2D) g;
       

        g2D.drawImage(bufferedimage , 0, 0, this);
    }
}
}