Which layer owns the behavior?

Goal & mental model verified

Learn which layer owns which concern. Java supplies the language and runtime. Framework supplies the container and application infrastructure. Boot assembles and configures applications. Portfolio projects add specialized capabilities.

Worked example · design exercise synthesis

For a quote API, start with Java, Boot, MVC, Data and Security. Add Batch for overnight reconciliation; add messaging when asynchronous delivery is required. A portfolio is a toolbox, not a dependency shopping list.

Engineering decision synthesis

Choose a compatible Boot generation first; let its dependency management align libraries. This reduces manual coordination but means an upgrade can change several components together.

Pitfall & diagnosis synthesis

“All Spring” is too broad for exhaustive API coverage. This atlas teaches major mechanisms and maps specialist projects; it does not document every method or cloud provider integration.

Improve & validate synthesis

Compare your actual dependency tree with the compatible project generations. Remove unused starters and track a reproducible runtime/build baseline.