Spring Boot 3.0.0 RC1 Release Notes

For changes in earlier milestones, please refer to:

Upgrading from Spring Boot 2.x

`server.max-http-header-size`

Previously, the server.max-http-header-size was treated inconsistently across the four supported embedded web servers. When using Jetty, Netty, or Undertow it would configure the max HTTP request header size. When using Tomcat it would configure the max HTTP request and response header sizes. To address this inconsistency, server.max-http-header-size has been deprecated and a replacement, server.max-http-request-header-size, has been introduced. Both properties now only apply to the request header size, irrespective of the underlying web server. To limit the max header size of an HTTP response on Tomcat or Jetty (the only two servers that support such a setting), use a WebServerFactoryCustomizer.

Updated Phases for Graceful Shutdown

The phases used by the SmartLifecycle implementations for graceful shutdown have been updated. Graceful shutdown now begins in phase SmartLifecycle.DEFAULT_PHASE - 2048 and the web server is stopped in phase SmartLifecycle.DEFAULT_PHASE - 1024. Any SmartLifecycle implementations that were participating in graceful shutdown should be updated accordingly.

Configuring Gradle Tasks

Spring Boot’s Gradle tasks have been updated to consistently use Gradle’s Property support for their configuration. As a result, you may need to change the way that you reference a property’s value. For example, the value of the imageName property on bootBuildImage can now be accessed using imageName.get(). Additionally, if you are using the Kotlin DSL, you may need to change the way that you set properties. For, example in Spring Boot 2.x, layering of the bootJar task could be disabled as follows:

tasks.named<BootJar>("bootJar") {
	layered {
		isEnabled = false
	}
}

In 3.0, the following must be used:

tasks.named<BootJar>("bootJar") {
	layered {
		enabled.set(false)
	}
}

Please refer to the Gradle plugin’s reference documentation for further examples.

Excluding Properties From build-info.properties With Gradle

As part of the previously described changes to configuring Gradle tasks, the mechanism for excluding properties from the generated build-info.properties file has also changed. Previously, properties could be excluded by setting them to null. This no longer works and has been replaced with a name-based mechanism:

springBoot {
	buildInfo {
		excludes = ['time']
	}
}

The equivalent in the Gradle Kotlin DSL is as follows:

springBoot {
	buildInfo {
		excludes.set(setOf("time"))
	}
}

Minimum Requirements Changes

None.

New and Noteworthy

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

GraalVM Native Image Support

This release represents the culmination of the efforts to support GraalVM native images in Spring Boot, Spring Framework, and the rest of the Spring portfolio. See the updated documentation for more information on creating GraalVM native images with Spring Boot.

More Flexible Auto-configuration for Spring Data JDBC

The auto-configuration for Spring Data JDBC is now more flexible. Several auto-configured beans that are required by Spring Data JDBC are now conditional and can be replaced by defining a bean of the same type. The types of the beans that can now be replaced are the following:

org.springframework.data.jdbc.core.JdbcAggregateTemplate
org.springframework.data.jdbc.core.convert.DataAccessStrategy
org.springframework.data.jdbc.core.convert.JdbcConverter
org.springframework.data.jdbc.core.convert.JdbcCustomConversions
org.springframework.data.jdbc.core.mapping.JdbcMappingContext
org.springframework.data.relational.RelationalManagedTypes
org.springframework.data.relational.core.dialect.Dialect

Support for Infinispan Reinstated

With its 14.0 release, Infinispan has added support for Jakarta EE 9. As a result, we have been able to reinstate support for Infinispan. Please note that, where available, the -jakarta variant of Infinispan’s modules should be used.

Auto-Configuration for Prometheus Exemplars

When there is a Micrometer Tracing Tracer bean and Prometheus is on the classpath, a SpanContextSupplier is now auto-configured. This supplier links metrics to traces by making the current trace ID and span ID available to Prometheus.

Log4j2 Enhancements

Log4j2 support has been updated with new extensions that provide the following functionality:

Profile-specific Configuration
Environment Properties Lookup
Log4j2 System Properties

For details, please see the updated documentation

Logback Configuration in a Native Image

logback.xml and logback-spring.xml can now be used to configure logging in an application that is compiled to a GraalVM native image.

Dependency Upgrades

Spring Boot 3.0.0-RC1 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 9.5.0
Hibernate 6.1.4.Final
Jackson 2.14.0-rc2
Jedis 4.3.0
Kafka 3.3.1
Kotlin 1.7.20
Lettuce 6.2.1.RELEASE
Liquibase 4.17.0
Log4j2 2.19.0
Logback 1.4.4
Micrometer 1.10.0-RC1
Micrometer Tracing 1.0.0-RC1
Mockito 4.8.1
MongoDB 4.8.0-beta0
Netty 4.1.84.Final
OpenTelemetry 1.19.0
SLF4J 2.0
SnakeYAML 1.33
Thymeleaf 3.1.0.RC1
Tomcat 10.0.27
Undertow 2.2.20.Final

Miscellaneous

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

When using spring-rabbit-stream, a RabbitStreamTemplate and Environment will now be auto-configured whether or not spring.rabbitmq.listener.type is stream.