Kafka Streams: Kafka Streams was introduced as part of thetech preview release of the Confluent Platform few months ago and is now available through Apache Kafka 0.10.0.0. Kafka Streams is a library that turns Apache Kafka into a full featured, modern stream processing system. Kafka Streams includes a high level language for describing common stream operations (such as joining, filtering, and aggregating records), allowing developers to quickly develop powerful streaming applications. Kafka Streams offers a true event-at-a-time processing model, handles out-of-order data, allows stateful and stateless processing and can easily be deployed on many different systems— Kafka Streams applications can run on YARN, be deployed on Mesos, run in Docker containers, or just embedded into existing Java applications.
There are some nice improvements in this latest version of Kafka.