20 important features of Spring Boot

Here’s a list of 20 new or important things you should know in Spring Boot today (2025) — ranging from features in recent releases, advanced patterns, integrations, and under-the-hood mechanisms:

1. Spring Boot 3.x and Jakarta EE Migration

Since Spring Boot 3, the entire codebase migrated from javax.* to jakarta.* packages.
This means libraries must be compatible with Jakarta EE 9+.

2. Virtual Threads (Project Loom) Support

Spring Boot 3.2+ adds virtual thread support in Tomcat, Jetty, Undertow, and WebFlux.
Configure via spring.threads.virtual.enabled=true.

3. Ahead-of-Time (AOT) Processing

Introduced for native images with GraalVM.
Spring Boot AOT engine optimizes configuration and bean creation at build-time to reduce startup time.

4. Observability with Micrometer + OpenTelemetry

Micrometer 2.x integrates directly with OpenTelemetry.
Unified APIs for metrics, logs, and tracing: spring.observability.enabled=true.

5. Spring Boot Docker Image Building (Buildpacks)

./mvnw spring-boot:build-image or Gradle plugin builds OCI images without a Dockerfile.
Uses Paketo buildpacks with layered JAR optimizations.

6. HTTP Interface Clients

Declarative HTTP clients (@HttpExchange) introduced in Spring 6.

Example:

@HttpExchange("/users")
interface UserClient {
    @GetExchange("/{id}") User getUser(@PathVariable int id);
}

7. Problem Details (RFC 7807) Error Handling

Spring Boot 3.1+ automatically produces problem+json responses for errors.
Unified format for REST API error responses.

8. Configuration Properties Scanning

Instead of @EnableConfigurationProperties, Spring Boot now detects @ConfigurationProperties beans automatically when annotated with @ConstructorBinding.

9. Testcontainers Auto-Configuration

Native Testcontainers support in Spring Boot 3.1+.
Add dependency, and @ServiceConnection wires DB, Kafka, Redis automatically for integration tests.

10. Declarative Retry & Resilience

Spring Retry and Resilience4j integrate more tightly.
Use annotations like @Retryable, @CircuitBreaker without heavy boilerplate.

11. `spring-modulith` Integration

Helps enforce modular architecture within monolithic Spring Boot apps.
Automatically documents module boundaries, dependencies, and runtime events.

12. Spring GraphQL

Now a first-class citizen (separate project).
Works with WebFlux and MVC with DataLoader and subscriptions support.

13. Native Query Support in Spring Data

Spring Data 3.x allows projections and DTO mapping directly in repository queries.
Also adds Querydsl 5.x support.

14. Kubernetes and Cloud-Native Configuration

Spring Boot integrates with Spring Cloud Kubernetes for ConfigMaps, Secrets, and Service discovery.
Health probes auto-configured for liveness/readiness endpoints.

15. Spring Boot Actuator Enhancements

New endpoints: /actuator/startup (startup steps), /actuator/configprops improvements.
Micrometer tags allow per-request metrics with low overhead.

16. CRaC (Coordinated Restore at Checkpoint) Support

Spring Boot apps can checkpoint JVM state and restore instantly (useful for serverless).
Experimental but promising for ultra-fast cold starts.

17. Functional Bean Registration

Beans can be registered programmatically with GenericApplicationContext.registerBean.
Useful for frameworks and DSLs built on Spring.

18. Context Lifecycle Events

New ApplicationStartup API for granular startup timing metrics.
Replaces custom ApplicationListener hacks for startup profiling.

19. Native Image Security

Security auto-config for Spring Security works in GraalVM native builds.
Classpath scanning replaced by hints for runtime reflection.

20. RSocket Support in Spring Boot

Integrated with Micrometer tracing.
Supports request-stream, request-channel, and backpressure directly with controllers.

⚡ These 20 items cover new features, best practices, integrations, and architecture shifts in Spring Boot up to 2025.

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