To use this code as is, you need to have kafka and zookeeper installed and running on default ports on localhost (as configured here within). You can download kafka from here and follow the instructions to start the server. You can download zookeeper from here and follow the instructions to start the server. Or, use your favorite installer such as Homebrew on Mac. Once you have kafka and zookeeper running, you can run the code in the following way:
tbradellis/vertx-kafka-clients
Producer and a Consumer for testing a new Java Agent instrumentation module
Java