Kafka has released 0.8.2 and meanwhile starts to using new producer API which is written in Java originally. Currently, we use javaapi written in scala in flume-ng-kafka-sink. I've added new Java API into current sink and re-write the tests with mockito.
As far as I know by reading the source code of kafka 0.8.2, new Java API of Consumer would seen be released soon. I think in the very soon, kafka API will all change into Java API.