Spring Boot 4.1.0 RC1 Release Notes

Spring Boot 4.1.0-RC1 Release Notes

For changes in earlier milestones, please refer to:

Upgrading from Spring Boot 4.0

New and Noteworthy

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

Load Layers Configuration from the Classpath with Maven

It is now possible to load the layers configuration that the Maven plugin should use to repackage the application. Custom layers should be placed in META-INF/spring/layers/<name>.xml and added as a plugin’s dependency.

Review the documentation for more details.

OpenTelemetry Support

Support has been added to read most of the OpenTelemetry environment variables (for example those, those, and those).

A complete list of all supported variables and their corresponding Spring Boot configuration property can be found in the documentation.

Lazy JDBC connection Fetching Support

Added a new spring.datasource.connection-fetch property (eager, lazy). When set to lazy, the auto-configured pooled DataSource is wrapped with LazyConnectionDataSourceProxy so a physical connection is taken from the pool only when a JDBC statement is actually needed.

@RedisListener auto-configuration

Add auto-configure for Spring Data Redis’s @RedisListener endpoints.

If the application does not define a RedisMessageListenerContainer, a default container is registered so listener methods can be discovered and invoked without extra wiring. See spring.data.redis.listener.* for a list of options. Applications that need additional containers can use RedisMessageListenerContainerConfigurer to apply the same defaults as auto-configuration when building their own RedisMessageListenerContainer beans.

The spring-boot-starter-data-redis starter now also declares a dependency on spring-messaging, which is required by this feature.

HTTP Client SSRF Mitigation with InetAddressFilter

Both reactive and blocking HTTP clients can now be configured with an InetAddressFilter which can block outgoing requests to specific addresses. This feature is useful for hardening your applications against SSRF attacks.

For more details on how to use the InetAddressFilter please see the updated reference documentation.

Dependency Upgrades

Spring Boot 4.1.0-RC1 moves to new versions of several Spring projects:

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

Miscellaneous

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

Application-wide HTML escaping configuration for webflux can be configured using spring.webflux.default-html-escape.
Console ANSI support is now enabled by default on Microsoft Windows 11 and later.
Add support for configuring closeTimeout and allowNonTransactional on KafkaTemplate.