Parts 1 and 2 left the application with every bean it needs and a correct home for every setting it reads. What neither of them touched is the process.

A process has properties that no properties file decides. How many requests it is allowed to hold at once, which is a concurrency model rather than a number. How a container's environment becomes something a JVM will accept, given that nothing hands a properties file to a container. What a log line looks like and where it lands, which no amount of logging.level configuration answers. And what the thing can tell you about itself at three in the morning, when the only question that matters is which version is running.

Those four are this part, and it ends with an image and a compose file, so that from here on the whole project starts with one command.…