What's New in Spring Framework 6.x

What's New in Version 6.1

Core Container

General compatibility with virtual threads and JDK 21 overall.
Configuration options for virtual threads: a dedicated VirtualThreadTaskExecutor and a virtual threads mode on SimpleAsyncTaskExecutor, plus an analogous SimpleAsyncTaskScheduler with a new-thread-per-task strategy and a virtual threads mode.
Lifecycle integration with Project CRaC for JVM checkpoint restore (see related documentation).
Lifecycle integrated pause/resume capability and parallel graceful shutdown for ThreadPoolTaskExecutor and ThreadPoolTaskScheduler as well as SimpleAsyncTaskScheduler.
Async/reactive destroy methods (e.g. on R2DBC ConnectionFactory); see 26691.
Async/reactive cacheable methods, including corresponding support in the Cache interface and in CaffeineCacheManager; see 17559 and 17920.
Reactive @Scheduled methods (including Kotlin coroutines); see 22924.
Observation instrumentation of @Scheduled methods; see 29883.
Selecting a specific target scheduler for each @Scheduled method; see 20818.
Validator factory methods for programmatic validator implementations; see 29890.
Validator.validateObject(Object) with returned Errors and Errors.failOnError method for flexible programmatic usage; see 19877.
MethodValidationInterceptor throws MethodValidationException subclass of ConstraintViolationException with violations adapted to MessageSource resolvable codes, and to Errors instances for @Valid arguments with cascaded violations. See 29825, and umbrella issue 30645.
Support for resource patterns in @PropertySource; see 21325.
Support for Iterable and MultiValueMap binding in BeanWrapper and DirectFieldAccessor; see 907 and 26297.
Revised Instant and Duration parsing (aligned with Spring Boot); see 22013.
Support for letters other than A-Z in property/field/variable names in SpEL expressions; see 30580.
Support for registering a MethodHandle as a SpEL function (see related documentation).

Data Access and Transactions

Common TransactionExecutionListener contract with before/afterBegin, before/afterCommit and before/afterRollback callbacks triggered by the transaction manager (for thread-bound as well as reactive transactions); see 27479.
@TransactionalEventListener and TransactionalApplicationListener always run in the original thread, independent from an async multicaster setup; see 30244.
@TransactionalEventListener and TransactionalApplicationListener can participate in reactive transactions when the ApplicationEvent gets published with the transaction context as its event source; see 27515.
A failed CompletableFuture triggers a rollback for an async transactional method; see 30018.
DataAccessUtils provides various optionalResult methods with a java.util.Optional return type; see 27735.
The new JdbcClient provides a unified facade for query/update statements on top of JdbcTemplate and NamedParameterJdbcTemplate, with flexible parameter options as well as flexible result retrieval options; see 30931.
SimplePropertyRowMapper and SimplePropertySqlParameterSource strategies for use with JdbcTemplate/NamedParameterJdbcTemplate as well as JdbcClient, providing flexible constructor/property/field mapping; see 26594.
SQLExceptionSubclassTranslator can be configured with an overriding customTranslator; see 24634.
BeanPropertyRowMapper and DataClassRowMapper available for R2DBC as well; see 30530.

Web Applications

Spring MVC and WebFlux now have built-in method validation support for controller method parameters with @Constraint annotations. That means you no longer need @Validated at the controller class level to enable method validation via AOP proxy. Built-in method validation is layered on top of the existing argument validation for model attribute and request body arguments. The two are more tightly integrated and coordinated, e.g. avoiding cases with double validation. See Upgrading to 6.1 for migration details, 29825 for more on the built-in support in M1, and the umbrella issue 30645 for related tasks and feedback.
ErrorResponse allows customization of ProblemDetail type via MessageSource and use of custom ProblemDetail through its builder.
Spring MVC throws NoHandlerFoundException or NoResourceFoundException (new in 6.1) to allow consistent handling of 404 errors, including with an RFC 7807 error response. See 29491.
The new RestClient is a synchronous HTTP client that offers an API similar to WebClient, using the same infrastructure as RestTemplate. See 29552.
Jetty-based ClientHttpRequestFactory for use with RestTemplate and RestClient; see 30564.
JDK HttpClient-based ClientHttpRequestFactory for use with RestTemplate and RestClient; see 30478.
Improved buffering in various ClientHttpRequestFactory implementations; see 30557.

Messaging Applications

Interface parameter annotations are detected for messaging handler methods as well (analogous to web handler methods).
The SpEL-based selector header support in WebSocket messaging is now disabled by default and must be explicitly enabled. See 30550 and Upgrading to 6.1 for migration details.

Testing

ApplicationContext failure threshold support: avoids repeated attempts to load a failing ApplicationContext in the TestContext framework, based on a failure threshold which defaults to 1 but can be configured via a system property (see related documentation).
Support for recording asynchronous events with @RecordApplicationEvents. See 30020.
- Record events from threads other than the main test thread.
- Assert events from a separate thread – for example with Awaitility.
Support for null in MockHttpServletResponse.setCharacterEncoding(). See 30341.

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.
New MockHttpServletRequestBuilder.setRemoteAddress() method.
The four abstract base test classes for JUnit 4 and TestNG no longer declare listeners via @TestExecutionListeners and instead now rely on registration of default listeners.