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Spring Boot 2.3 Release Notes
Spring Boot now requires:
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Gradle 6.3+ (if you are building with Gradle). 5.6.x is also supported but in a deprecated form.
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Jetty 9.4.22+ (if you are using Jetty as the embedded container)
As of #19550, Web and WebFlux starters do not depend on the validation starter by default anymore.
If your application is using validation features, for example you find that javax.validation.* imports are not being resolved, you’ll need to add the starter yourself.
For Maven builds, you can do that with the following:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>For Gradle, you will need to add something like this:
dependencies {
...
implementation 'org.springframework.boot:spring-boot-starter-validation'
}Spring Boot 2.3 ships with a major release of Spring Data. Some extra care is required if you are using Cassandra, Couchbase, Elasticsearch or MongoDB.
As of #16230, the default BootstrapMode for JPA repositories is now "deferred" so as to improve startup time. You can revert that new default with the spring.data.jpa.repositories.bootstrap-mode=default configuration property.
This release switches to Cassandra v4 that brings a number of backward incompatible changes.
If you were relying on ClusterBuilderCustomizer to customize the Cluster, this concept no longer exists in v4 and has been replaced by two more specific customizers:
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DriverConfigLoaderBuilderCustomizercustomizes the properties of the driver. Please use this for any property that is not exposed yet. -
CqlSessionBuilderCustomizercustomizes theCqlSession(formerSession).
The Cassandra v4 driver no longer has automatic local DC inference from contact points.
As a result, the "local-datacenter" property must be set with the default load balancing policy and the contact points must be of that data center.
A new spring.data.cassandra.local-datacenter property has been added to easily set the local datacenter.
This release switches to Couchbase SDK v3 that brings a number of backward incompatible changes.
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To connect to a cluster, you should now use
spring.couchbase.connection-stringinstead of the formerspring.couchbase.bootstrap-hosts. -
Role-based access controls have now been generalized.
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Spring Boot no longer auto-configures a
Bucketbut you can easily do so using theClusterAPI. -
Endpoints IO configuration has been harmonized in
spring.couchbase.env.io. -
If you were extending
CouchbaseConfigurationto customize the environment, please useClusterEnvironmentBuilderCustomizerto do so in a more idiomatic fashion.
A bucket name needs to be provided if you’re using Couchbase with Spring Data.
The deprecated Native Elasticsearch transport has been removed as both Elasticsearch and Spring Data themselves won’t support it in their next releases. Support for the Jest library has also been removed in this release.
Spring Boot is now using Elasticsearch 7.5+ by default.
This release switches to MongoDB 4 and harmonizes the reactive and imperative drivers. This should be pretty transparent to you if you’re using the starter.
With this harmonization, the non reactive infrastructure is no longer provided if you use spring-boot-starter-data-mongodb-reactive.
If you need to use the imperative infrastructure on startup (e.g. MongoOperations), consider adding spring-boot-starter-data-mongodb.
The open session in view interceptor for Neo4j is now disabled by default.
If you need to enable it again, use the standard spring.data.neo4j.open-in-view property.
The details of the Neo4j health indicator now contains the version and edition of the server, as shown in the following example:
neo4j: {
status: "UP",
details: {
edition: "community",
version: "4.0.0"
}
}This release upgrades to Micrometer 1.5 which brings a number of deprecations:
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Service Level Agreements have been renamed to Service Level Objectives and the boundary is expressed as a
doublerather than along. -
Wavefront metrics are now exported via
WavefrontSender. As a result the read and connection timeout properties are no longer honoured.
This release upgrades to Jackson 2.11 which includes a change to the default formatting of java.util.Date and java.util.Calendar. Please see FasterXML/jackson-databind#2643 for details.
The Spring Cloud Connectors starter was deprecated in 2.2 in favor of Java CFEnv. This starter has been removed, and Spring Cloud Connectors dependencies are no longer included in Spring Boot’s managed dependencies.
The configuration properties for configuring the threads used by embedded Servlet web servers (Jetty, Tomcat, and Undertow) have moved to dedicated threads groups.
The properties can now be found in server.jetty.threads, server.tomcat.threads, and server.undertow.threads.
The old properties remain in a deprecated form to ease migration.
The error message and any binding errors are no longer included in the default error page by default.
This reduces the risk of leaking information to a client.
server.error.include-message and server.error.include-binding-errors can be used to control the inclusion of the message and binding errors respectively.
Supported values are always, on-param, and never.
The auto-configured disk space health indicator no longer requires the path that is monitored to exist when the application starts. A non-existent path will be detected as having zero usable space resulting in a down response from the indicator.
The developmentOnly configuration, primarily intended for use when declaring a dependency on Spring Boot’s DevTools, is now created automatically by Spring Boot’s Gradle plugin.
Any manual configuration of developmentOnly can be removed from your Gradle build scripts.
Spring Boot’s build no longer makes use of site plugin (maven-site-plugin) and plugin management for it has been removed. If you were relying on Spring Boot’s managed versions, you should add your own plugin management.
If you inherit from spring-boot-starter-parent, it no longer configures Maven’s exec plugin (exec-maven-plugin) to set the main class using start-class. If you were relying on that, you can restore that behaviour as follows:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<configuration>
<mainClass>${start-class}</mainClass>
</configuration>
</plugin>For consistency with SpringApplication, ApplicationContextRunner now disables bean overriding by default.
If you need to use bean overriding for a test, withAllowBeanDefinitionOverriding can be used to enable it.
Profile names that contain commas are now supported with the @ActiveProfiles annotation.
This means that an annotation like @ActiveProfiles("p1,p2") will treat the provided value p1,p2 as a single profile name.
To activate multiple profiles, provide each profile name as a separate value as in @ActiveProfiles({"p1","p2"}).
As part of introducing support for graceful shutdown, web server initialisation is now performed at the end of application context refresh processed rather than immediately after refresh processing has completed. As a result, the WebServerInitializedEvent is now published before the ContextRefreshedEvent.
Most classes, methods and properties that were deprecated in Spring Boot 2.2 have been removed in this release. Please ensure that you aren’t calling deprecated methods before upgrading.
A number of properties have been renamed or deprecated.
You can use the spring-boot-properties-migrator module to identify those properties.
Once added as a dependency to your project, this will not only analyze your application’s environment and print diagnostics on startup, but also temporarily migrate properties at runtime for you.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-properties-migrator</artifactId>
<scope>runtime</scope>
</dependency>runtime("org.springframework.boot:spring-boot-properties-migrator")|
Note
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Once you’re done with the migration, please make sure to remove this module from your project’s dependencies. |
|
Tip
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Check the configuration changelog for a complete overview of the changes in configuration. |
Support for building Docker images using Cloud Native Buildpacks and has been added to the Maven and Gradle plugins via the spring-boot:build-image goal and the bootBuildImage task.
The Paketo Java buildpack is used by default to create images.
Support for building jar files with contents separated into layers has been added to the Maven and Gradle plugins. The layering separates the jar’s contents based on how frequently they will change. This separation allows more efficient Docker images to be built. Existing layers that have not changed can be reused with the layers that have changed being placed on top.
Depending on your application, you may want to tune how layers are created and add new ones. This can be done using configuration that describes how the jar can be separated into layers, and the order of those layers.
When you create a layered jar, the spring-boot-jarmode-layertools jar will be added as a dependency to your jar by default (this can be disabled with build configuration).
With this jar on the classpath, you can launch your application in a special mode which allows the bootstrap code to run something entirely different from your application, for example, something that extracts the layers.
To see the options available, launch a fat jar with -Djarmode=layertools as shown in the following example:
$ java -Djarmode=layertools -jar my-app.jar
Usage:
java -Djarmode=layertools -jar my-app.jar
Available commands:
list List layers from the jar that can be extracted
extract Extracts layers from the jar for image creation
help Help about any commandFat jars built with Maven and Gradle now include an index file. When the jar is exploded, this index file is used to ensure that the ordering of the classpath is the same as when executing the jar directly.
Spring Boot now supports wildcard locations when loading configuration files.
By default, a wildcard location of config/*/ outside of your jar is supported.
This is useful in an environment such as Kubernetes when there are multiple sources of config properties.
For instance, if you have separate mysql and redis configurations, they can be picked automatically if you place them in /config, i.e. /config/mysql/application.properties and /config/redis/application.properties.
Graceful shutdown is supported with all four embedded web servers (Jetty, Reactor Netty, Tomcat, and Undertow) and with both reactive and Servlet-based web applications.
When enabled using server.shutdown=graceful, upon shutdown, the web server will no longer permit new requests and will wait for a grace period for active requests to complete. The grace period can be configured using spring.lifecycle.timeout-per-shutdown-phase. Please see the reference documentation for further details.
Spring Boot now has built-in knowledge of the availability of your application, tracking whether it is alive and whether it is ready to handle traffic.
The health endpoint can be configured to expose the liveness (/actuator/health/liveness) and readiness (/actuator/health/readiness) of you application with the management.health.probes.enabled=true configuration property.
When running on Kubernetes this is done automatically.
To learn more about this feature, please check out this blog post and the reference documentation to which it links.
Spring Boot 2.3 ships with a major Spring Data release. Please see the Spring Data Neumann goes GA to learn more.
When r2dbc is on the classpath, a ConnectionFactory is auto-configured with a similar arrangement than a jdbc DataSource.
If Spring Data is on the classpath, repositories are auto-configured as well, as usual.
R2DBC support also adds an health indicator for the connection factory, metrics for ConnectionPool and a test slice, @DataR2dbcTest.
The base path of all web handlers a WebFlux application can now be configured. Use the spring.webflux.base-path property to do so.
The conversion of time and date-time values in web applications is now configurable via application properties.
This complements that existing support for formatting date values.
For MVC, the properties are spring.mvc.format.time and spring.mvc.format.date-time respectively.
For WebFlux, the properties are spring.webflux.format.time and spring.webflux.format.date-time respectively.
In addition to taking a typical formatting pattern, the properties for configuring the formatting of dates, times, and date-times now support a value of iso.
When set, the corresponding ISO-8601 formatting will be applied.
The iso values is supported by the following properties:
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spring.mvc.format.date -
spring.mvc.format.date-time -
spring.mvc.format.time -
spring.webflux.format.date -
spring.webflux.format.date-time -
spring.webflux.format.time
As of #17886, the /actuator/configprops endpoint provides end-to-end information about configuration properties, aligning its behavior with the environment endpoint.
For example, after adding server.server-header=Spring Boot in your application.properties, the endpoint will show you the following:
"serverHeader": {
"origin": "class path resource [application.properties]:2:22",
"value": "Spring Boot"
},Metrics names available at /actuator/metrics/ are now ordered alphabetically which makes it easier to find what you are looking for.
In the absence of a validation query, the datasource HealthIndicator now operates in query-less mode, using java.sql.Connection#isValid to validate the connection.
Tags that are used in addition to those provided by default for MVC and WebFlux can now be contributed.
Contributions can be made using a WebMvcTagsContributor @Bean for MVC and a WebFluxTagsContributor @Bean for WebFlux.
The auto-configuration for Wavefront has been updated to define a WavefrontSender bean.
This allows publishing of both metrics and traces to Wavefront over a single connection.
Kafka metrics are published natively for the consumers and producers created by the auto-configured ConsumerFactory and ProducerFactory.
To produce metrics for components created by a custom factory, you should add a listener as shown in the following example:
factory.addListener(new MicrometerConsumerListener<>(meterRegistry));|
Note
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If you were enabling JMX support for the sole purpose of collecting Kafka metrics this is no longer necessary. |
Spring Boot now provides auto-configuration for Spring Integration’s RSocket support.
If spring-integration-rsocket is available, developers can configure an RSocket server using "spring.rsocket.server.*" properties and let it use IntegrationRSocketEndpoint or RSocketOutboundGateway components to handle incoming RSocket messages.
If a property needs to express a period of time, you can do so using a java.time.Period property.
Similar to the Duration support, an easy format is supported (i.e. 10w for 10 weeks) as well as metadata support.
A new @WebServiceClientTest annotation has been added to support “slice” testing of Web Services.
Spring Boot 2.3 moves to new versions of several Spring projects:
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Spring Data Neumann
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Spring HATEOAS 1.1
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Spring Integration 5.3
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Spring Kafka 2.5
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Spring Security 5.3
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Spring Session Dragonfruit
Please note that Spring Boot 2.3 builds against the same Spring Framework and Reactor generation as Spring Boot 2.2.
Numerous third-party dependencies have also been updated, some of the more noteworthy of which are the following:
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Artemis 2.12
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AssertJ 3.16
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Cassandra Driver 4.6
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Couchbase Client 3.0
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Elasticsearch 7.6
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Flyway 6.4
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Hibernate Validator 6.1
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Infinispan 10.1
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Jackson 2.11
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JUnit Jupiter 5.6
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Kafka 2.5
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Kotlin 1.3.72
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Lettuce 5.3
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Micrometer 1.5
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Mockito 3.3
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MongoDB 4.0
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QueryDSL 4.3
Apart from the changes listed above, there have also been lots of minor tweaks and improvements including:
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Configuration defaults were updated in our JPA support to improve the testing experience, see #16230 and #16747.
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The output from
spring-boot-autoconfigure-processoris now repeatable, making it work better with Gradle’s build cache. -
The Couchbase’s type key can be configured via
spring.data.couchbase.type-key. -
OAuth2 parameter binding is now available with
@WebMvcTest. -
Jetty’s backing queue can be configured using
server.jetty.max-queue-capacity. -
Liquibase’s tag support can be configured using
spring.liquibase.tag. Clearing all checksums in the current changelog is now available via thespring.liquibase.clear-checksumsproperty. -
Gradle metadata is now published.
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DataSourceBuildercan be used to configure aSimpleDriverDataSource. -
DataSourcemetrics have now a description. -
Auto-detection of the cloud platform can be overridden using
spring.main.cloud-platform. -
Caching of responses from Actuator’s HTTP endpoints is now supported when the request has a principal.
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Maven support for creating a fat jar now honors the
project.build.outputTimestampproperty, allowing its output to be reproducible. -
The Javadoc of the Maven plugin is now published.
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A customizer interface,
RSocketMessageHandlerCustomizer, is provided for customizing the auto-configuredRSocketMessageHandler, -
A customizer interface,
DefaultCookieSerializerCustomizer, is provided for customizing the auto-configuredDefaultCookieSerializer. -
Auto-configuration of the default servlet can now be disabled by setting
server.servlet.register-default-servlettofalse. -
A new condition,
@ConditionalOnWarDeploymenthas been added. It can be used to detect when an application has been deployed as a war to a Servlet container or application server. -
The properties migrator handles all deprecated properties, not only those with error levels.
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JDBC drivers are deregistered when destroying the war’s ServletContext.
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Redis’s sentinel password can be configured using
spring.redis.sentinel.password.
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The
spring.http.properties have been moved toserver.servlet.encoding.,spring.mvc.andspring.codec., see #18827. -
SpringApplication#refresh(ApplicationContext)has been deprecated in favour ofSpringApplication#refresh(ConfigurableApplicationContext). -
The
ON_TRACE_PARAMused with theserver.error.include-stacktraceproperty has been renamed toON_PARAM. -
org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientBuilderCustomizerhas been deprecated in favor oforg.springframework.boot.autoconfigure.elasticsearch.RestClientBuilderCustomizer