title: Display modal box while servlet is processing
body: <p>I am trying to show user a modal box in a java servlet with message - "Please wait while your request is processed". 
  I know I can do a ajax call and handle the modal in the front end code. I am currently opening the servlet on click of a button by the user. Servlet takes around 2 minutes to process. Is there any way I can show processing  box when servlet starts executing and hide it once it ends?</p>