API

• Stabilize synchronous gauge (#6419)

Incubator

• Add put(AttributeKey<T>, T) overload to EventBuilder (#6331)

Baggage

• Baggage filters space-only keys (#6431)

SDK

• Add experimental scope config to enable / disable scopes (i.e. meter, logger, tracer) (#6375)

Traces

• Add ReadableSpan#getAttributes (#6382)
• Use standard ArrayList size rather than max number of links for initial span links allocation (#6252)

Metrics

• Use low precision Clock#now when computing timestamp for exemplars (#6417)
• Update invalid instrument name log message now that forward slash / is valid (#6343)

Exporters

• Introduce low allocation OTLP marshalers. If using autoconfigure, opt in via OTEL_JAVA_EXPERIMENTAL_EXPORTER_MEMORY_MODE=REUSABLE_DATA. * Low allocation OTLP logs marshaler (#6429) * Low allocation OTLP metrics marshaler (#6422) * Low allocation OTLP trace marshaler (#6410) * Add memory mode support to OTLP exporters (#6430) * Marshal span status description without allocation (#6423) * Add private constructors for stateless marshalers (#6434)
• Mark opentelemetry-exporter-sender-jdk stable (#6357)
• PrometheusHttpServer prevent concurrent reads when reusable memory mode (#6371)
• Ignore TLS components (SSLContext, TrustManager, KeyManager) if plain HTTP protocol is used for exporting (#6329)
• Add is_remote_parent span flags to OTLP exported Spans and SpanLinks (#6388)
• Add missing fields to OTLP metric exporters toString() (#6402)

Extensions

• Rename otel.config.file to otel.experimental.config.file for autoconfigure (#6396)

OpenCensus Shim

• Fix opencensus shim spanBuilderWithRemoteParent behavior (#6415)

Tooling

• Add additional API incubator docs (#6356)
• Run build on java 21 (#6370)
• Fix running tests with java 8 on macos (#6411)
• Move away from deprecated gradle enterprise APIs (#6363)

🙇 Thank you

This release was possible thanks to the following contributors who shared their brilliant ideas and awesome pull requests:

@AlexanderWert @anuraaga @arosien @breedx-splk @gavin-nia @jack-berg @jimshowalter @jkwatson @johnbley @laurit @LikeTheSalad @oliver-zhang @serkan-ozal @tkmsaaaam @trask @tylerbenson