What's New in Spring Framework 6.x

What's New in Version 6.0

JDK 17+ and Jakarta EE 9+ Baseline

Entire framework codebase based on Java 17 source code level now.
Migration from "javax" to "jakarta" namespace for Servlet, JPA, etc.
Compatible with latest web container generation: Tomcat 10, Jetty 11.
Early compatibility with virtual threads (in preview as of JDK 19).

General Core Revision

Upgrade to ASM 9.4 and Kotlin 1.7.
Complete CGLIB fork with support for capturing CGLIB-generated classes.
Comprehensive foundation for Ahead-Of-Time transformations.
First-class support for GraalVM native images (see related Spring Boot 3 blog post).

Core Container

Basic bean property determination without java.beans.Introspector by default.
AOT processing support in GenericApplicationContext ("refreshForAotProcessing").
Bean definition transformation based on pre-resolved constructors and factory methods.
Support for early proxy class determination for AOP proxies and configuration classes.
PathMatchingResourcePatternResolver uses NIO and module path APIs for scanning.
DefaultFormattingConversionService supports ISO-based default java.time type parsing.

Data Access and Transactions

Support for pre-determining JPA managed types (for inclusion in AOT processing).
JPA support for Hibernate ORM 6.1 (retaining compatibility with Hibernate ORM 5.6).
Upgrade to R2DBC 1.0 (including R2DBC transaction definitions).
Removal of JCA CCI support.

Spring Messaging

RSocket interface client based on @RSocketExchange service interfaces.
Early support for Reactor Netty 2 based on Netty 5 alpha.

General Web Revision

HTTP interface client based on @HttpExchange service interfaces.
Support for RFC 7807 problem details.
Unified HTTP status code handling.

Spring MVC

PathPatternParser used by default (with the ability to opt into PathMatcher).
Removal of outdated Tiles and FreeMarker JSP support.

Spring WebFlux

New PartEvent API to stream multipart form uploads (both on client and server).
Addition of ResponseEntityExceptionHandler to customize WebFlux exceptions and render RFC 7807 error responses.
Flux return values for non-streaming media types (no longer collected to List before written).
Early support for Reactor Netty 2 based on Netty 5 alpha.
JDK HttpClient integrated with WebClient.

Observability

Direct Observability instrumentation with Micrometer Observation in several parts of the Spring Framework. The "spring-web" module now requires "io.micrometer:micrometer-observation:1.10+" as a compile depedency.

RestTemplate and WebClient are instrumented to produce HTTP client request observations
Spring MVC can be instrumented for HTTP server observations using the new org.springframework.web.filter.ServerHttpObservationFilter
Spring WebFlux can be instrumented for HTTP server observations using the new org.springframework.web.filter.reactive.ServerHttpObservationFilter
Integration with Micrometer Context Propagation for Flux and Mono return values from controller methods.