Inside Spring Boot 4: Restructuring for the Future
summary
Spring Boot 4 breaks the big auto-config jar into many focused modules, shrinking runtime artifacts and changing package names so upgrades require replacing old starters with Spring Boot Starter Classic then swapping in technology-specific starters; build times drop from ~7 minutes to ~30 seconds for localized changes. Undertow and Pulsar Reactive are removed, Jackson moves to tools.jackson (JSON mapper) and JSpecify adds ~9,000 nullable annotations, HTTP service clients and API versioning gain built-in support while Rest Test Client gets auto-configuration.
AI-written summary · about
chapters (11)
- 0:00Introduction
- 1:13Spring Boot 4 requirements
- 3:19Modularization changes
- 8:22Maintainability benefits
- 10:08New starter structure
- 13:57Migration guide
- 25:36Jackson 3 upgrade
- 32:57Spring Retry updates
- 38:58HTTP client API
- 42:31Miscellaneous changes
- 44:42Q&A
related talks
38mWhat Is Spring?
45mBootiful Spring Boot 3.x
56mBuilding a Framework on top of Spring Boot
43mInside Spring: The Architecture Behind the Framework
34mSpring Tools 4 - A look behind the scenes
56mSpring For Architects
01h 04mMind the Gap: Jumping from Spring Boot 2.x to 3.x
24mSpring Tools 4: Bootiful Spring Tooling for the Masses