Spring Boot's application.properties file and its application.yaml counterpart are key to creating flexible and configurable Java applications.

Spring is an easy choice for adding a range of Java-based capabilities, including the well-designed Spring Boot Web project for handling endpoints and routing.

The Spring Boot @ConfigurationProperties simplifies the use of the application.properties file, easing the creation of lists, maps and inner classes.

It is a Spring Boot web application at heart, and can be configured with command-line arguments via --spring.profiles.active=your-active-profile.