Version 1.16.0

API

• Fix bug ImmutableKeyValuePairs implementation that causes ArrayIndexOutOfBoundsException to be thrown under certain conditions.

SDK

Traces

• Optimize BatchSpanProcessor using JcTools.

Metrics

• Tighten up exponential histogram implementation for alignment with specification: Default to 160 positive and negative buckets. Remove ability to configure starting scale. Minimum number of buckets is one instead of zero.
• Allow MetricExporter and MetricReader to influence default aggregation. The default aggregation is used when no registered views match an instrument.

Exporter

• Fix handling of client keys in PEM format.
• For OTLP exporters, change behavior to use OkHttpGrpcExporter (OkHttp implementation that doesn't use any gRPC dependencies) unless OtlpGrpc{Signal}Builder#setChannel(ManagedChannel) is called by user. Previously, OkHttpGrpcExporter was used if no gRPC implementation was found on classpath.
• Add support to configure default aggregation on OTLP metric exporters via Otlp{Protocol}MetricExporterBuilder#setDefaultAggregationSelector(DefaultAggregationSelector).

Testing

• Add span status assertions.

SDK Extensions

• Autoconfigure properly handles non-string system properties.
• Autoconfigure normalizes hyphens - to periods . when accessing ConfigProperties.

OpenTracing Shim

• Add support for span wrappers.
• Store OpenTracing SpanContext in OpenTracing Span wrapper.
• Use Baggage of active span.

🙇 Thank you

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

@aaron-ai
@anuraaga
@breedx-splk
@carlosalberto
@codeboten
@cuichenli
@fax4ever
@HaloFour
@jack-berg
@jkwatson
@jsuereth
@mateuszrzeszutek
@mohitmahi
@pavolloffay
@pureklkl
@trask
@xiangtianyu
@zeitlinger