Spring Boot 4 arrives alongside Spring Framework 7, upgrading to Jakarta EE 11, JDK 25, JSpecify null‑safety, build‑time optimizations, a declarative HTTP client, full Jackson 3 support, native API versioning, built‑in resilience, OpenTelemetry integration, and a dual‑track Spring AI strategy.
Spring Boot 4 launches alongside Spring Framework 7, Spring Data 2025.1 and Spring AI 1.1, introducing Jakarta EE 11, JDK 25, JSpecify null‑safety, build‑time optimizations with Project Leyden, a new declarative HTTP client, Jackson 3 support, native API versioning, built‑in resilience, OpenTelemetry integration, and a dual‑track AI strategy.
Spring Boot 4.0, built on Spring Framework 7.0, introduces HTTP Service Clients, native API versioning, full JSpecify null‑safety, Java 25 support, upgraded dependencies, Gradle 9 compatibility, Redis static master‑replica configuration, and drops Undertow, with migration advice to move through 3.5 first.
Spring Boot 4 adopts JSpecify’s null‑safety annotations, replacing JSR‑305, to make nullability explicit at compile time; using @NullMarked and @Nullable with tools like NullAway, developers can catch potential NPEs early, reduce defensive checks, improve API contracts, and handle collections and parameters more safely.
Spring Boot 4 and the entire Spring family now implement full null‑safety by adopting JSpecify annotations, enabling compile‑time checks that eliminate NullPointerException, while providing a roadmap for future Java platform null‑type support and detailing the upgraded modules and tooling.
Spring Boot 4 now embraces JSpecify’s null‑safety annotations, allowing developers to declare nullable and non‑null types at compile time; combined with the NullAway static analyzer, this shift eliminates mysterious NullPointerExceptions in production by making null contracts explicit, reducing defensive code, and improving maintainability.
Spring Boot 4.0 (SNAPSHOT) introduces built‑in Spring Framework 7.0 support, elegant API versioning via @RequestMapping, flexible bean registration, virtual thread integration for massive concurrency, JSpecify null‑safety annotations, enhanced SPEL, Jackson 3.x migration, servlet upgrades, and native GraalVM image support, all illustrated with code samples.
