0. make a jar out of the 2 Java files

1. throw the jar into ringos lib folder

2. add this to your action.js:

exports.captcha = function(req) {
   importClass(Packages.com.funqtional.util.Captcha);
   var cap = new Captcha();
   var resp = {'img':capt.make()};
   req.session.data.captcha = cap.phrase();
   return Response.json(resp);
}

3. add this to your page the JQuery way (as a macro, or any other way ...). The page
contains a <div id='captcha'></div>:

<script type="text/javascript">
   $(function() {
       $.post('captcha', function(data) {
           imageData = data.img;
           var img = $('<img>')
                   .attr('src', 'data:image/jpeg;base64,' +
imageData)
           $('#captcha').append(img);
       });
   });
</script>

In the validation code you would then compare the captcha String from
req.postParams with the one stored in req.session.data.captcha.