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Spring Boot 3.0.0 M3 Release Notes

Scott Frederick edited this page May 19, 2022 · 28 revisions

Spring Boot 3.0.0 M3 Release Notes

For changes in earlier milestones, please refer to:

Upgrading from Spring Boot 2.x

Minimum Requirements Changes

None.

Actuator Metrics Export Properties

We have moved the properties controlling the actuator metrics export. The old schema was management.metrics.export.<product>, the new one is management.<product>.metrics.export (Example: the prometheus properties moved from management.metrics.export.prometheus to management.prometheus.metrics.export). If you are using the spring-boot-properties-migrator, you will get notified at startup. See #30381 for details.

Simplifed Main Class Name Resolution with Gradle

When building an application with Gradle, resolution of the name of the application’s main class has been simplified and made consistent. bootJar, bootRun, and bootWar now all resolve the name of the main class name by looking for it in the output of the main source set. This removes a small risk that the tasks may not have used the same main class name by default. If you were relying on the main class being resolved from a location outside of the main source set’s output, update your Gradle configuration to configure the main class name using the mainClass property of the springBoot DSL:

springBoot {
    mainClass = "com.example.Application"
}

Alternatively, you can configure the classpath property of the resolveMainClassName task to search in locations other than the main source set’s output directories.

Running Your Application in the Maven Process

The fork attribute of spring-boot:run and spring-boot:start that was deprecated in Spring Boot 2.7 has been removed.

SAML2 Relying Party Configuration

Support for properties under spring.security.saml2.relyingparty.registration.{id}.identity-provider have been removed. Use the new properties under spring.security.saml2.relyingparty.registration.{id}.asserting-party as a replacement.

Embedded MongoDB

Auto-configuration and dependency management for Flapdoodle embedded MongoDB has been removed. If you are using embedded MongoDB for testing, use the auto-configuration library provided by the Flapdoodle project or modify the tests to use the Testcontainers project instead of embedded MongoDB.

Logging Date Format

The default format for the date and time component of log messages for Logback and Log4j2 has changed to align with the ISO-8601 standard. The new default format yyyy-MM-dd’T’HH:mm:ss.SSSXXX uses a T to separate the date and time instead of a space character and adds the timezone offset to the end. The LOG_DATEFORMAT_PATTERN environment variable or logging.pattern.dateformat property can be used to restore the previous default value of yyyy-MM-dd HH:mm:ss.SSS.

Support for Apache Solr Removed

Support for Apache Solr has been removed as its Jetty-based client, Http2SolrClient, is not compatible with Jetty 11.

Auto-configuration of Micrometer’s JvmInfoMetrics

Micrometer’s JvmInfoMetrics is now auto-configured. Any manually configured JvmInfoMetrics bean definition can be removed.

New and Noteworthy

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

Reinstated Support for REST Assured

With its 5.0 release, REST Assured is compatible with Jakarta EE 9 and Groovy 4.0. As a result, support has been reinstated.

Reinstated Support for Pooled JMS

With its 5.0 release, Pooled JMS is compatible with Jakarta EE 9. As a result, support has been reinstated and can be used with Apache Artemis by setting spring.artemis.pool.enabled to true.

Auto-configuration for Micrometer Observation API

Spring Boot now auto-configures an instance of ObservationRegistry for you. If micrometer-core is on the classpath, a TimerObservationHandler is registered on the ObservationRegistry, which means that every stopped Observation leads to a timer. ObservationPredicate, GlobalTagsProvider and ObservationHandler are automatically registered on the ObservationRegistry. You can use ObservationRegistryCustomizer to further customize the ObservationRegistry if you need to. See #29666 for details.

Auto-configuration for Micrometer Tracing

Spring Boot now auto-configures Micrometer Tracing for you. This includes support for Brave, OpenTelemetry, Zipkin and Wavefront. When using the Micrometer Observation API, finishing observations will lead to spans reported to Zipkin or Wavefront. Tracing can be controlled with properties under management.tracing. Zipkin can be configured with management.zipkin.tracing, while Wavefront uses management.wavefront. To use, for example Wavefront with Brave, these dependencies are needed:

implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'io.micrometer:micrometer-tracing-bridge-brave'
implementation 'io.micrometer:micrometer-tracing-reporter-wavefront'

Auto-configuration for Micrometer’s OtlpMeterRegistry

An OtlpMeterRegistry is now auto-configured when io.micrometer:micrometer-registry-otlp is on the classpath. The meter registry can be configured using management.otlp.metrics.export.* properties.

Enabling Async Acks with Apache Kafka

A new configuration property, spring.kafka.listener.async-acks, for enabling async acks with Kafka has been added. To enable async acks, set the property to true. The property only applies when spring.kafka.listener.async-mode is set to manual or manual-immediate.

Dependency Upgrades

Spring Boot 3.0.0-M3 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:

  • Flyway 8.5.11

  • Hibernate 5.6.9.Final

  • Micrometer 1.10.0-M2

  • Micrometer Tracing 1.0.0-M5

  • Netty 4.1.77.Final

  • Reactor Bom 2022.0.0-M2

  • Thymeleaf 3.1.0.M2

  • Tomcat 10.0.21

Miscellaneous

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

  • Bean Validation Configuration can now be customised by defining a ValidationConfigurationCustomizer bean.

  • Log4j2’s Log4jBridgeHandler is now used to route JUL-based logging into Log4j2 rather than routing through SLF4J.

Deprecations in Spring Boot 3.0

  • The properties management.metrics.export.<product> are deprecated, the replacement is management.<product>.metrics.export. See above for more details.

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