On November 16, 2022, Juergen Hoeller made the announcement that Spring Framework 6 will be officially released. Spring 6 is a major release, more than four years after the release of Spring 5. Let’s take a quick look at the exciting features in the Spring 6 release in this article.

JDK 17+ and Jakarta EE 9+ baseline

  • Entire framework code base now based on Java 17 source level.
  • Servlet, JPA, etc. migrated from javax to Jakarta namespace.
  • Runtime compatibility with Jakarta EE 9 and Jakarta EE 10 APIs.
  • Compatibility with the latest web servers: Tomcat 10.1, Jetty 11, Undertow 2.3.
  • Early compatibility with virtual threads (previewed from JDK 19).

General core revisions

  • Upgrade to ASM 9.4 and Kotlin 1.7.
  • Complete CGLIB fork with support for capturing CGLIB generated classes.
  • Full transition to AOT (Ahead-Of-Time Processing).
  • First-class support for GraalVM native images.


  • By default, no java.beans.Introspector is required to determine the base bean properties.
  • Support for AOT processing in GenericApplicationContext (refreshForAotProcessing).
  • Bean definition transformation based on pre-parsed constructors and factory methods.
  • Support for early proxy class determination for AOP proxies and configuration classes.
  • PathMatchingResourcePatternResolver scans using NIO and module path APIs, supporting class path scanning in GraalVM native images and Java module paths, respectively.
  • DefaultFormattingConversionService supports ISO-based default java.time type resolution.

Data access and transactions

  • Support for scheduled JPA managed types (for inclusion in AOT processing).
  • JPA support for Hibernate ORM 6.1 (maintains compatibility with Hibernate ORM 5.6).
  • Upgraded to R2DBC 1.0 (includes R2DBC transaction definitions).
  • Removed JCA CCI support.

Spring Messaging

  • RSocket interface client based on the @RSocketExchange service interface.
  • Early support for Reactor Netty 2 based on Netty 5 Alpha.
  • Support for Jakarta WebSocket 2.1 and its standard WebSocket protocol upgrade mechanism.


  • HTTP interface client based on the @HttpExchange service interface.
  • Support for RFC 7807 problem details.
  • Unified HTTP status code handling.
  • Support for Jackson 2.14.
  • Alignment with Servlet 6.0 (while retaining runtime compatibility with Servlet 5.0).

Spring MVC

  • PathPatternParser used by default (ability to opt into PathMatcher).
  • Remove deprecated Tiles and FreeMarker JSP support.

Spring WebFlux

  • New PartEvent API for streaming multipart form uploads (both on client and server).
  • New ResponseEntityExceptionHandler for customizing WebFlux exceptions and rendering RFC 7807 error responses.
  • Flux return values for non-streaming types (List is no longer collected before writing).
  • Early support for Reactor Netty 2 based on Netty 5 Alpha.
  • JDK HttpClient integration with WebClient.


  • Micrometer Observation is partially used in the Spring Framework. spring-web module now requires io.micrometer:micrometer-observation:1.10+ as a compiled dependency.
  • RestTemplate and WebClient are detected as generating HTTP client request observations.
  • Spring MVC can use the new org.springframework.web.filter.ServerHttpObservationFilter to detect HTTP server observations.
  • Spring WebFlux can use the new org.springframework.web.filter.reactive.ServerHttpObservationFilter to detect HTTP server observations.
  • For Flux and Mono’s Micrometer Context Propagation integration, return values from controller methods.


  • Support for testing application contexts for AOT processing on JVM or in GraalVM native images.
  • Integration with HtmlUnit 2.64 + request parameter handling.
  • Servlet mockups (MockHttpServletRequest, MockHttpSession) are now based on Servlet API 6.0.


Reference https://waylau.com/new-features-and-enhancements-in-spring-framework-6/