Spring Boot applications do not always have to serve as a web service located on the Internet. You can also use Spring Boot (or Spring without the Boot) for a command-line utility. I was recently faced with this task, and one requirement for the tool was to support setting a profile-specific configuration on the command line. This isn’t earth-shattering per se since that is a regular Spring feature. The goal was to provide a profile-specific configuration file on the command line that is not bundled in the application.
Imagine developing a Cloud service and running different environments for the different phases of your project – one for development tests, a staging environment, and, finally, the production environment. Connecting to the different environments may require secrets you do not want to be bundled in the application – and, thus, the source tree.
Now, you could roll your own configuration file reader. But wouldn’t it be nice to make full support of Spring’s @Value annotation or @ConfigurationProperties classes?
The Codeslinger 