At this time, we only email you about updates to specific articles you've specified you want to watch.
However, there are some other tools at your disposal:
You can fetch an RSS feed of all new topics tagged with java. You can receive notifications by plugging this RSS feed into an RSS reader. Or, you can use something like IFTTT to send you alerts, text messages, tweets, facebook posts, or even flicker the lights in your smart home, etc., each time the RSS feed has been updated.
Additionally, if you want to do something creative and roll your own RSS parser, our RSS feeds use PubSubHubbub, which means you can get notified for updates via PUSH notifications instead of having to poll.
You can use our JSON feed to fetch all topics tagged with java, sorted by when they were last posted in. You will, unfortunately, have to write your own parser / reader / notification system (or perhaps one already exists somewhere on the web, probably a Github repository somewhere that would only need slight modifications to make it work).
Our complete API documentation is available at https://www.daniweb.com/welcome/api