What's New in Spring Framework 6.x

What's New in Version 6.1

Core Container

• First-class configuration options for virtual threads on JDK 21.
• Lifecycle integration with Project CRaC for JVM checkpoint restore.
• Support for resolving SequencedCollection/Set/Map at injection points.
• Support for registering a MethodHandle as a SpEL function.
• Validator factory methods for programmatic validator implementations.

Data Access and Transactions

• Failed CompletableFuture triggers rollback for async transactional method.

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.
• Runtime compatibility with Jakarta EE 9 as well as Jakarta EE 10 APIs.
• Compatible with latest web servers: Tomcat 10.1, Jetty 11, Undertow 2.3.
• 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, enabling support for classpath scanning within a GraalVM native image and within the Java module path, respectively.
• DefaultFormattingConversionService supports ISO-based default java.time type parsing.

Data Access and Transactions

• Support for predetermining 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).
• Aligned data access exception translation between JDBC, R2DBC, JPA and Hibernate.
• 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.
• Support for Jakarta WebSocket 2.1 and its standard WebSocket protocol upgrade mechanism.

General Web Revision

• HTTP interface client based on @HttpExchange service interfaces.
• 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 (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).
• New 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 dependency.

• 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.

Testing

• Support for testing AOT-processed application contexts on the JVM or within a GraalVM native image.
• Integration with HtmlUnit 2.64+ request parameter handling.
• Servlet mocks (MockHttpServletRequest, MockHttpSession) are based on Servlet API 6.0 now.