Spring Boot 4 Brings Full Null‑Safety Across the Spring Ecosystem with JSpecify

Spring announced that Spring Boot 4 and the entire Spring ecosystem now fully support null‑safety by adopting the JSpecify annotation standard, allowing developers to eliminate NullPointerException at compile time.

Historically, Java lacks explicit nullability, so NPEs were caught only at runtime via comments or IDE hints. JSpecify defines standard annotations such as @NullMarked, @Nullable and @NonNull to express nullability contracts.

These annotations are tool‑agnostic and recognized by IntelliJ IDEA, NullAway, Eclipse, etc. Spring has deprecated its own org.springframework.lang annotations and migrated to JSpecify.

After months of work, the following Spring projects now provide null‑safe APIs:

Spring Boot 4.0

Spring Framework 7.0

Spring Data 4.0

Spring Security 7.0

Spring Batch 6.0

Spring Integration 7.0

Spring Kafka 4.0

Spring GraphQL 2.0

Spring Web Services 5.0

Spring HATEOAS 3.0

Micrometer 1.16

Reactor 2025.0

Future releases will extend null‑safety to components such as Spring AI, Spring Session, and Spring LDAP.

Developers can use the Gradle Nullability plugin together with Spring Boot 4 and IntelliJ IDEA 2025.3 (upcoming) to enforce null contracts during compilation, effectively preventing NPEs.

The move prepares the Spring ecosystem for upcoming Java platform features like Null‑Restricted and Nullable types, which will eventually enable runtime performance optimizations.

References

JSpecify project: https://github.com/jspecify/jspecify