1.16.0

We upgraded the Prometheus Java Client to 1.4.x (#6830) which brings support for Unicode which includes some behavioral change in naming conventions, see the 1.16 Migration-Guide.

⚠️ Noteworthy

• Deprecate the Wavefront module #6328
• Remove deprecated io.micrometer.core.lang annotations #6407
• Register JCache cache.removals as a FunctionCounter by default #2754
• Improve no-op behavior of the Observation API #6700

⭐ New Features

• Support KeyValues with annotations when using ObservedAspect/@Observed #4030
• Validate low cardinality keys #6713
• Add counter for total loaded classes #3561
• Add eventexecutor.workers metrics for Netty #6375
• Avoid DistributionStatisticsConfig creation when retrieving timers #6661
• Avoid capturing lambda allocation when retrieving existing meters #6670
• Introduce MeterConvention #6710
• OpenTelemetry Semantic Conventions for JVM metrics #5286
• Add MeterFilter.forMeters utility method #6594
• Apache HC 5 OTel semantic convention #6591
• Improve nullability for gauges #6546
• Metrics for Generational Shenandoah GC #4259
• Support custom tags in NettyEventExecutorMetrics #6592
• Support newsgroups KeyValue for Jakarta Mail instrumentation #6558
• Add KeyName.withNoneValue() #6125
• Add getAll to Getter for repeated metadata #6312
• Enhance logging of negative amount in AbstractTimer.record() by printing stack trace #6530
• Flag to register JCache cache.removals as FunctionCounter #6471
• Improved Meter.Id#getTags() performance #6182
• Jakarta Mail instrumentation #5985
• Log requests as trace level for OtlpMeterRegistry #6514
• Make KafkaMetrics refresh interval configurable #6319
• Migrate to JSpecify annotations for nullability constraints #5547
• Provide meter count in HighCardinalityTagsDetector #6510
• StackdriverConfig option to not create metric descriptors #6281
• Use String.replace() where possible #6449

🐞 Bug Fixes

• Exclude java.* from OSGI Import-Package #6810
• Distribution without percentiles always has value 0 in Stackdriver #6401
• Incompatible with slf4j 2 in OSGi #6406
• LongTaskTimer#measure does not return max duration #6421
• Return NaN for null KafkaMetrics values #6324
• Scrape failure when conflicting meter types are registered #6434
• ValueResolver and ValueExpressionResolver nullability is inconsistent #6280

📔 Documentation

• Add a note about client-side percentiles with histogram #6836
• Add docs for HighCardinalityTagsDetector #6822
• Polish Javadoc from gh-6319 #6376

🔨 Dependency Upgrades

• Upgrade Micrometer Context Propagation to 1.2.0 #6860
• Bump ch.qos.logback:logback-classic from 1.5.19 to 1.5.20 #6813
• Bump com.google.auth:google-auth-library-oauth2-http from 1.34.0 to 1.40.0 #6801
• Bump com.google.cloud:google-cloud-monitoring from 3.63.0 to 3.79.0 #6818
• Bump com.google.cloud:libraries-bom from 26.60.0 to 26.71.0 #6826
• Bump com.netflix.spectator:spectator-reg-atlas from 1.8.12 to 1.9.1 #6793
• Bump io.prometheus:prometheus-metrics-bom from 1.3.6 to 1.4.2 #6830
• Bump software.amazon.awssdk:cloudwatch from 2.31.41 to 2.37.5 #6834
• Bump com.dynatrace.metric.util:dynatrace-metric-utils-java from 2.2.1 to 2.4.0 #6739
• Bump dropwizard-metrics from 4.2.30 to 4.2.37 #6729
• Bump io.opentelemetry.proto:opentelemetry-proto from 1.5.0-alpha to 1.7.0-alpha #6290

📝 Tasks

• Remove optional jsr305 dependency where not needed #6493
• Require explicit constraints in @contract #6568

❤️ Contributors

Thank you to all the contributors who worked on this release:
@isanghaessi, @izeye, @peterjeschke, @genuss, @etki, @Shaderbug, @MemencioPerez, @famaridon, @msqr, @scordio, @jbertram, @HeeChanN, @ttaehee, @deadok22, @pema4, and @thonra