Microblogging engine in Java

Is anybody aware of any open source Twitter/Identica开发者_StackOverflow-like microblogging engines written in Java? My basic requirements are that users should be able to

1. Write short comments on some entities in the web application
2. Customize privacy features, like "do not show name/email"
3. Like/dislike comments

and optionally, track user locations.

The ones I've found so far were written in ASP.net (Yonkly), PHP (StatusNet, Floopo, Jisko) or Python (Jaiku).

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You could start with the Atmosphere Framework with its JQuery plugin to implement Comet techniques.

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It's a few years after the question, granted. I thought it might not hurt to add a comment, though, here in the knowledge web.

Though it's not per se a matter of conventional microblogging, but Apache Roller provides a conventional blogging framework and API, in Java - in a sort of superset of patterns in microblogging. FYI, documentation for Roller 5.0.1 is here - there may've been a bad link, at the site...

As far as measuring "Like" feedback, there are services such as ShareThis, such that one could integrate with Roller, at the presentation level - perhaps, using Wicket or Vaadin, at that same application level. Granted, it's not a closely integrated feedback system that would make for - may not provide a lot of close integration between the content presentation and the visitor feedback components, if one's using a local API for the content management and social service like ShareThis for the content feedback - but ShareThis, in particular, does integrate with popular social networking services, and it's available. Hope it helps!

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Another "years later" answer, but I had the same issue and created a service around it, http://www.collabinate.com. I would be interested to know if it would meet the needs of your use case.