Spring Boot 2.6.0 M2 Release Notes

Upgrading from Spring Boot 2.5

Deprecations from Spring Boot 2.4

Classes, methods and properties that were deprecated in Spring Boot 2.4 have been removed in this release. Please ensure that you aren’t calling deprecated methods before upgrading.

Records and `@ConfigurationProperties`

If you are using @ConfigurationProperties with a Java 16 record and the record has a single constructor, it no longer needs to be annotated with @ConstructorBinding. If your record has multiple constructors, @ConstructorBinding should still be used to identify the constructor to use for property binding.

Dependency Management for org.jboss:jboss-transaction-spi removed

Dependency management for org.jboss:jboss-transaction-spi has been removed. If you are using org.jboss:jboss-transaction-spi you should define your own dependency management that meets your application’s needs.

The 7.12 release of Flyway moved the Vault-related settings to a closed-source extension. Unfortunately, this prevents Spring Boot from configuring them. As a result, the corresponding spring.flyway.vault-secrets, spring.flyway.vault-token, and spring.flyway.vault-url properties have been removed. If you are a Flyway Teams user, the settings can be configured via a FlywayConfigurationCustomizer bean, FluentConfigiguration.getExtensionConfiguration and the Vault ApiExtension

Circular References Prohibited by Default

Circular references between beans are now prohibited by default. If your application fails to start due to a BeanCurrentlyInCreationException you are strongly encouraged to update your configuration to break the dependency cycle. If you are unable to do so, circular references can be allowed again by setting spring.main.allow-circular-references to true, or using the new setter methods on SpringApplication and SpringApplicationBuilder This will restore 2.5’s behaviour and automatically attempt to break the dependency cycle.

Minimum Requirements Changes

None.

New and Noteworthy

Tip	Check the configuration changelog for a complete overview of the changes in configuration.

MessageSource-based Interpolation of Bean Validation Messages

The application’s MessageSource is now used when resolving {parameters} in constraint messages. This allows you to use your application’s messages.properties files for Bean Validation messages. Once the parameters have been resolved, message interpolation is completed using Bean Validation’s default interpolator.

Using WebTestClient for Testing Spring MVC

Developers could use WebTestClient to test WebFlux apps in mock environments, or any Spring web app against live servers. This change also enables WebTestClient for Spring MVC in mock environments: classes annotated with @AutoConfigureMockMvc can get injected a WebTestClient. This makes our support complete, you can now use a single API to drive all your web tests!

Auto-configuration for spring-rabbit-stream

Auto-configuration for Spring AMQP’s new spring-rabbit-stream module has been added. A StreamListenerContainer is auto-configured when the spring.rabbitmq.listener.type property is set to stream. The spring.rabbitmq.stream.* properties can be used to configure access to the broker and spring.rabbitmq.listener.stream.native-listener can be used to enable native listener support.

Additional Path for Health Groups

Health groups can be made available at an additional path on either the main or management port. This is useful in cloud environments such as Kubernetes, where it is quite common to use a separate management port for the actuator endpoints for security purposes. Having a separate port could lead to unreliable health checks because the main application might not work properly even if the health check is successful. A typical configuration would have all the actuator endpoints on a separate port and health groups that are used for liveness and readiness available at an additional path on the main port.

Health Groups with Composite Contributors

Health groups can be configured to include/exclude parts of a CompositeHealthContributor. This can be done by specifying the fully qualified path to the component. For example, a component spring which is nested inside a composite named test, can be included using test/spring.

Network Configuration for Docker Image Building

A network configuration parameter has been added to the Maven plugin spring-boot:build-image goal and the Gradle bootBuildImage task. This parameter can be used to configure the network driver used by the container that runs the Cloud Native Buildpacks builder process.

Dependency Upgrades

Spring Boot 2.6 M2 moves to new versions of several Spring projects:

Numerous third-party dependencies have also been updated, some of the more noteworthy of which are the following:

Artemis 2.18
Commons DBCP 2.9
Commons Pool 2.11
Couchbase Client 3.2
Flyway 7.13
Jolokia 1.7
QueryDSL 5.0

Miscellaneous

Apart from the changes listed above, there have also been lots of minor tweaks and improvements including:

The heapdump endpoint is now supported on OpenJ9 where it will produce a heap dump in PHD format.
New configuration properties are now supported for multipart support in WebFlux, under spring.webflux.multipart.*
Any ContainerCustomizer bean is now called to configure the auto-configured Spring AMQP MessageListenerContainer
Jackson’s default leniency can be configured using the spring.jackson.default-leniency property.
Distribution statistic’s expiry and buffer length are now configurable.