Groking Streaming

Streaming systems minimize the time between an event and information processing, so you receive results in real-time. In financial applications, security issues, and IoT, every millisecond is important, so streaming systems are indispensable. Moreover, it's trendy and profitable ;) !... No wonder specialists in Spark, Heron, and Kafka are in high demand.
Finally, you can get acquainted with the creation of streaming applications and event processing in real-time without struggling through the technical details of specific frameworks, perplexing terms, and complex formulations. Simple language and vivid examples will allow you to learn the basic concepts, and to grasp the described ideas and techniques, you will build your own simple streaming program from scratch.

No experience with streaming systems is required from the reader. The examples are written in Java.