Spring Boot 4.1.0 M3 Release Notes

Spring Boot 4.1.0-M3 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.

File Rotation Support for Log4j

Support for configurable file rotation has been added for Log4j, with four strategies:

size (default): Rolls files based on their size.
time: Rolls files based on a time interval.
size-and-time: Rolls when both size and time conditions are met.
cron: Rolls based on a cron expression schedule.

Docker Compose

In the event of a failure when it calls docker compose up or docker compose start, Spring Boot’s Docker Compose support will now log the output of docker compose logs. The log message is output at the level specified by spring.docker.compose.start.log-level. It defaults to info.

OpenTelemetry enhancements

The new property management.opentelemetry.enabled can be used to disable the OpenTelemetry SDK. It then uses no-op implementations for the SdkTracerProvider, SdkLoggerProvider and SdkMeterProvider, but still configures the propagators. Additionally, it doesn’t create the tracing and logging beans which would be superfluous for a disabled SDK.

Properties have been added to configure OpenTelemetry’s BatchLogRecordProcessor, similar to the properties for BatchSpanProcessor.

A new property management.opentelemetry.tracing.sampler has been added for configuring OpenTelemetry’s sampler.

There’s also auto-configuration for SpanLimits and LogLimits, with properties under management.opentelemetry.tracing.limits. and management.opentelemetry.logging.limits. to configure them.

Support for OTLP exemplars has been added to Micrometer’s OtlpRegistry. This will automatically be configured if you’re using metrics over OTLP and Micrometer Tracing.

BuildInfo Gradle Task

By default, the BuildInfo Gradle task now produces a file named META-INF/build-info.properties in its configured destination directory. Previously, the file was named build-info.properties. The new filename property can be used to customize the name and, if required, restore the previous name.

The buildInfo methods on the Spring Boot DSL have been updated to improve the configuration of task inter-dependencies. The destination directory of the bootBuildInfo task is now configured as a source directory of the main source set’s resources. This improves the visibility of the generated file in IDEs that do not delegate to Gradle. It also provides Gradle with better information about the tasks' interdependencies and the relationship between their inputs and outputs.

Dependency Upgrades

Spring Boot 4.1.0-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:

Miscellaneous

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

A new FailureAnalyzedException has been added and can be used when you want to throw an exception that include its own failure analysis.
OAuth2 resource servers can now be configured in non-webapps.
Empty objects in YAML files are now rained in the resulting PropertySource.