Ajax and Comet provide a good combination for asynchronous communication between client-server and server-client, respectively. But what is their support/integration level in Java frameworks? Ajax has had more time to mature in Java framewokrs unlike Comet which is a more recent technique. This post by Matt Raible discusses Comet and its support in Java frameworks. Read Matt's post 'Dojo/Comet support in Java Web Frameworks': http://raibledesigns.com/rd/entry/dojo_comet_support_in_java