Errata: December 19
Thank you for purchasing Vert.x in Action. Please list any errors you find not listed below in the book's liveBook Errata thread. We'll update this list as necessary. Corrections are made to all formats during the book's second printing. Thank you!

In chapter 8, page 175, listing 8.27

The CONTAINERS field of type DockerComposeContainer allows TestContainers to start containers from a Docker Compose file. Due to a peculiarities in how TestContainers supports Docker Compose, it may be necessary to explicitly await for containers to be exposed, or test executions can sometimes fail because a container port hasn't been exposed yet. This can be done by calling the withExposedService method, as in:

private static final DockerComposeContainer CONTAINERS = new DockerComposeContainer(new File("../docker-compose.yml"))
  .withExposedService("mongo_1", 27017);

The changes have been applied to the samples source code repository at https://github.com/jponge/vertx-in-action.