Throw ValidatorException in JSF Validator

When throwing exception from a validator,
remember to throw ValidatorException instead of FacesException,
else the message component might be not able to display the correct validation message.

public void validAbc(FacesContext context, UIComponent component, Object value) {

   // some validation logic
  if(value.equals("abc")) {
    // proceed 
  } else {
    throw  new ValidatorException(new FacesMessage(
        FacesMessage.SEVERITY.ERROR, null, "validation error message"));
  }
}

Done!!

Simple Captcha by PrimeFaces graphicImage

Basically the concept is to generate random text and display it with image, which is <p:graphicImage />.

1. Write a method to generate the StreamedContent.

public StreamedContent getCaptcha() {
    StreamedContent 2dText = null;
    try {
        BufferedImage bufferedImg = new BufferedImage(
                100, 25, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = bufferedImg.createGraphics();
        
        String captchaText = generateRandomString();            
        
        g2.drawString(captchaText, 0, 10);
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        ImageIO.write(bufferedImg, "png", os);
        2dText = new DefaultStreamedContent(
                new ByteArrayInputStream(os.toByteArray()), "image/png"); 
    } 
    catch (Exception e) {
        e.printStackTrace();
    }
    return 2dText;
}