I'm sorry to say that there's no drop-in SDCH server library for any language, including Java. SDCH is generally unavailable to all except those willing to build their own server modules and interfaces. It's a disappointing situation...
From there you'll need server integration, which you'll have to wire up yourself.
Diffable was trying to build something in Java, but I think the project is dead at this point. There might be
some code here.
Cheers,
Joe Duarte