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

• 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.

Data Access and Transactions

• Support for pre-determining JPA managed types (for inclusion in AOT processing).
• JPA support for Hibernate ORM 6 (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.
• Micrometer-based observability for RestTemplate.

Spring MVC

• PathPatternParser used by default (with the ability to opt into PathMatcher).
• Integration with Micrometer Context Propagation for Flux and Mono return values from controller methods.
• Removal of outdated Tiles and FreeMarker JSP support.

Spring WebFlux

• Introduce PartEvent 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.
• Micrometer-based observability for WebClient.

Testing

• Support for testing AOT-processed application contexts.
• Integration with HtmlUnit 2.64 request parameter handling.