Beyond @SpringBootApplication: Building Custom Ecosystems on Top of Spring Boot

Writing a starter is easy. The real challenge is making it work in a diverse ecosystem with various Java and Spring Boot versions without breaking neighboring services or becoming an integration headache.

We’ll dive into the real-world challenges of building platform-level solutions on top of the Spring Framework. Using examples from open-source projects like Axelix and Spring Boot itself, we will address four specific questions:

1. How to register beans dynamically when their number is unknown in advance? We’ll explore different approaches and discuss what’s new in Spring Framework 7.
2. How to support a starter across different Spring Boot versions simultaneously? We’ll discuss architectural patterns and their trade-offs.
3. How to test auto-configurations quickly and in isolation? We’ll break down ApplicationContextRunner, context caching, and the changes introduced in Spring Framework 7.
4. How to guarantee that your starter/library works across different Java versions? We’ll discuss why this is crucial and see how the Spring Boot project itself handles this.

All topics will be demonstrated through a single end-to-end platform starter development scenario. Each topic is self-contained and provides immediate practical value.