CHANGELOG.md - platform/external/opencensus-java - Git at Google

 ## Unreleased

 - fix: Shutdown `MetricServiceClient` properly on `StackdriverStatsExporter.unregister()` (#2007)

 ## 0.28.3 - 2021-01-12

 - fix: Return public access to unsafe `ContextUtils` api.  Remove bincompat issue from 0.27.1. (#2072)
 - fix: When time rewinds, avoid throwing exceptions and crashing the disruptor thread. (#2071)

 ## 0.28.2 - 2020-10-22

 - feat: Make TracerImpl public for OpenTelemetry migration. (#2064)

 Note: no binary available for 0.28.2

 ## 0.28.1 - 2020-10-21

 - feat: Add Support for Opencensus to OpenTelemetry migration (#2059)

 Breaking change: ContextUtils is no longer public

 ## 0.28.0 - 2020-10-21

 - Remove finalize from RecordEventsSpanImpl (#2043)

 ## 0.27.0 - 2020-08-14
 - deps: update protobuf (#2029)
 - Update release versions for all readme and build files. (#2028)
 - deps: update Guava to 29.0 (#2032)
 - Add more InstanaExporterHandler tests (#2014)
 - feat: Allow users to specify a metric display name prefix, separately from the metric name prefix (#2050)

 ## 0.26.0 - 2020-03-19
 - feat: Allow users to register the same Meter multiple times without exception (#2017)
 - update gRPC (#2024): Since gRPC v1.27.0, census dependency is removed from grpc-core. A grpc-census
 artifact now exists to provide interceptor/stream tracer factory that applies census stats/tracing features.
 For users not using gRPC’s integration of census, nothing should be affected. Users who want census integration
 need to add grpc-census artifact to runtime classpath.
 - deps: update GSON (#2025)
 - deps: update auth libraries (#2023)
 - update guava (#2018)

 ## 0.25.0 - 2020-02-12
 - Add an experimental artifact `opencensus-contrib-observability-ready-util`, that allows users to
 use OpenCensus easily.

 ## 0.24.0 - 2019-08-27
 - Remove `CONTEXT_SPAN_KEY` and `TAG_CONTEXT_KEY` from API. This will be a breaking change to those who
 depend on these two keys, but anyone except gRPC shouldn't use it directly anyway.

 ## 0.23.0 - 2019-06-12
 - Make `StackdriverStatsExporter.unregister()` a public API.
 - Add support spring plugin for http servlet and AsyncRestTemplate.

 ## 0.22.1 - 2019-05-21
 - Increase the buffer size for the trace export batch to 2500 (previously it was 32).

 ## 0.22.0 - 2019-05-14
 - Disable RunningSpanStore by default unless the z-pages contrib is linked and initialized. This may
 break behaviors for applications that rely on this to be always enabled.
 - Provide a `Deadline` option to Stackdriver Trace exporter. Default value is 10 seconds if it's not set.
 - Provide a `Deadline` option to Stackdriver Stats exporter. Default value is 10 seconds.
 Also provide a `MetricServiceStub` option so that advanced users can use a custom Stackdriver
 Monitoring client to make RPCs.
 - Use `Configuration` builder pattern for creating `JaegerTraceExporter`, `ZipkinTraceExporter` and
 `InstanaTraceExporter`. Provide a `Deadline` option with default value 10 seconds.
 - Provide a `Deadline` option to Datadog, Elasticsearch and OcAgent exporter. Default value is 10 seconds.
 - Extract the common timeout logic of Trace exporters to `opencensus-exporter-trace-util`.

 ## 0.21.0 - 2019-04-30
 - Add HTTP text format serializer to Tag propagation component.
 - Support constant labels in Gauge APIs.
 - Add an option to allow users to override the default "opencensus_task" metric label in Stackdriver Stats Exporter.
 - Allow setting custom namespace in Prometheus exporter.
 - Add Cumulative (`DoubleCumulative`, `LongCumulative`, `DerivedDoubleCumulative`, `DerivedLongCumulative`) APIs.
 - Add convenience APIs `TagContextBuilder.putLocal()` that adds non-propagating tags,
 and `TagContextBuilder.putPropagating()` that adds unlimited propagating tags.
 - Deprecate context keys for tags and spans. Provide helper methods for interacting with context.

 ## 0.20.0 - 2019-03-28
 - Add OpenCensus Java OC-Agent Trace Exporter.
 - Add OpenCensus Java OC-Agent Metrics Exporter.
 - Add config option for Http-Servlet.
 - Add config option for Jetty Http Client.
 - Modified default value to false for publicEndpoint property in Http-Servlet.
 - Add a generic `AttachmentValue` class to support `Exemplar`.
 - Add Elasticsearch Trace Exporter.
 - Add `metrics.data` package to hold common classes shared between stats and metrics.
 - Refactor `Exemplar` and `AttachmentValue` to be under `metrics.data`. Note that this is a breaking change
 if you're using the `Exemplar` classes or APIs in the previous releases.
 - Add `TagMetadata` that defines the properties associated with a `Tag`.
 - Add `QueueMetricProducer` that supports pushing and buffering `Metric`s.

 ## 0.19.0 - 2019-01-28
 - Add an artifact `opencensus-contrib-http-jetty-client` for instrumenting jetty http client. Add extractor for Jetty Client.
 - Add an artifact `opencensus-contrib-http-servlets` for instrumenting http servlets. Add extractor for Http Servlets.
 - Add support generic http server handler.
 - Add support for generic http client handler.
 - Add ability to filter metrics collected from Dropwizard registry.
 - Add an util artifact opencensus-contrib-dropwizard5 to translate Dropwizard metrics5 to OpenCensus.
 - Add metrics util package to be shared by all metrics exporters.
 - Add Datadog Trace Exporter.

 ## 0.18.0 - 2018-11-27
 - Set the
   [`trace_sampled` field](https://github.com/googleapis/googleapis/blob/8027f17420d5a323c7dfef1ae0e57d82f3b97430/google/logging/v2/log_entry.proto#L143-L149) in the Stackdriver `LogEntry` protocol buffer in `opencensus-contrib-log-correlation-stackdriver`.
 - Add support for w3c/distributed-tracing propagation format.
 - Add gRPC measures and views for real-time metrics in streaming RPCs.
 - Add Summary Metric support for Stackdriver exporter.
 - Reduce CPU usage for low qps applications.

 ## 0.17.0 - 2018-11-02
 - Add `AttributeValueDouble` to `AttributeValue`.
 - Add `createWithSender` to `JaegerTraceExporter` to allow use of `HttpSender`
   with extra configurations.
 - Add an API `Functions.returnToString()`.
 - Migrate to new Stackdriver Kubernetes monitored resource. This could be a breaking change
   if you are using `gke_container` resources. For more info,
   https://cloud.google.com/monitoring/kubernetes-engine/migration#incompatible
 - Add an util artifact `opencensus-contrib-dropwizard` to translate Dropwizard metrics to
   OpenCensus.
 - Add Gauges (`DoubleGauge`, `LongGauge`, `DerivedDoubleGauge`, `DerivedLongGauge`) APIs.
 - Update `opencensus-contrib-log-correlation-log4j2` and
   `opencensus-contrib-log-correlation-stackdriver` to match the
   [OpenCensus log correlation spec](https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/LogCorrelation.md)
   and remove all `ExperimentalApi` annotations.
 - The histogram bucket boundaries (`BucketBoundaries`) and values (`Count` and `Sum`) are no longer
   supported for negative values. The Record API drops the negative `value` and logs the warning.
   This could be a breaking change if you are recording negative value for any `measure`.
 - Remove support for min/max in the stats Distribution to make it compatible with Metrics.

 ## 0.16.1 - 2018-09-18
 - Fix ClassCastException in Log4j log correlation
   ([#1436](https://github.com/census-instrumentation/opencensus-java/issues/1436)).
 - Allow users to report metrics for their registered domain (using custom prefix). This could be a
   breaking change if you have custom prefix without (registered) domain.

 ## 0.16.0 - 2018-09-14
 - Add APIs to register gRPC client and server views separately.
 - Add an API MeasureMap.putAttachment() for recording exemplars.
 - Add Exemplar class and an API to get Exemplar list to DistributionData.
 - Improve the styling of Rpcz, Statsz, Tracez, and Traceconfigz pages.
 - Add an artifact `opencensus-contrib-exemplar-util` that has helper utilities
   on recording exemplars.
 - Reduce the default limit on `Link`s per `Span` to 32 (was 128 before).
 - Add Spring support for `@Traced` annotation and java.sql.PreparedStatements
   tracing.
 - Allow custom prefix for Stackdriver metrics in `StackdriverStatsConfiguration`.
 - Add support to handle the Tracestate in the SpanContext.
 - Remove global synchronization from the get current stats state.
 - Add get/from{Byte} methods on TraceOptions and deprecate get/from{Bytes}.
 - Add an API to `StackdriverTraceConfiguration` to allow setting a
   `TraceServiceStub` instance to be used for export RPC calls.
 - Add an experimental artifact, `opencensus-contrib-log-correlation-log4j2`, for
   adding tracing data to Log4j 2 LogEvents.

 ## 0.15.1 - 2018-08-28
 - Improve propagation performance by avoiding doing string formatting when calling checkArgument.

 ## 0.15.0 - 2018-06-20
 - Expose the factory methods of MonitoredResource.
 - Add an experimental artifact, `opencensus-contrib-log-correlation-stackdriver`, for
   correlating traces and logs with Stackdriver Logging.

 ## 0.14.0 - 2018-06-04
 - Adds Tracing.getExportComponent().shutdown() for use within application shutdown hooks.
 - `Duration.create` now throws an `IllegalArgumentException` instead of
   returning a zero `Duration` when the arguments are invalid.
 - `Timestamp.create` now throws an `IllegalArgumentException` instead of
   returning a zero `Timestamp` when the arguments are invalid.
 - Remove namespace and help message prefix for Prometheus exporter. This could be
   a breaking change if you have Prometheus metrics from OpenCensus Prometheus exporter
   of previous versions, please point to the new metrics with no namespace instead.
 - Add an util artifact `opencensus-contrib-appengine-standard-util` to interact with the AppEngine
   CloudTraceContext.
 - Add support for Span kinds. (fix [#1054](https://github.com/census-instrumentation/opencensus-java/issues/1054)).
 - Add client/server started_rpcs measures and views to RPC constants.

 ## 0.13.2 - 2018-05-08
 - Map http attributes to Stackdriver format (fix [#1153](https://github.com/census-instrumentation/opencensus-java/issues/1153)).

 ## 0.13.1 - 2018-05-02
 - Fix a typo on displaying Aggregation Type for a View on StatsZ page.
 - Set bucket bounds as "le" labels for Prometheus Stats exporter.

 ## 0.13.0 - 2018-04-27
 - Support building with Java 9.
 - Add a QuickStart example.
 - Remove extraneous dependencies from the Agent's `pom.xml`.
 - Deprecate `Window` and `WindowData`.
 - Add a configuration class to the Prometheus stats exporter.
 - Fix build on platforms that are not supported by `netty-tcnative`.
 - Add Jaeger trace exporter.
 - Add a gRPC Hello World example.
 - Remove usages of Guava collections in `opencensus-api`.
 - Set unit "1" when the aggregation type is Count.
 - Auto detect GCE and GKE Stackdriver MonitoredResources.
 - Make Error Prone and FindBugs annotations `compileOnly` dependencies.
 - Deprecate `Mean` and `MeanData`.
 - Sort `TagKey`s in `View.create(...)`.
 - Add utility class to expose default HTTP measures, tags and view, and register
   default views.
 - Add new RPC measure and view constants, deprecate old ones.
 - Makes the trace and span ID fields mandatory in binary format.
 - Auto detect AWS EC2 resources.
 - Add `Duration.toMillis()`.
 - Make monitored resource utils a separate artifact `opencensus-contrib-monitored-resource-util`,
   so that it can be reused across exporters.
 - Add `LastValue`, `LastValueDouble` and `LastValueLong`. Also support them in
   stats exporters and zpages. Please note that there is an API breaking change
   in methods `Aggregation.match()` and `AggregationData.match()`.

 ## 0.12.3 - 2018-04-13
 - Substitute non-ascii characters in B3Format header key.

 ## 0.12.2 - 2018-02-26
 - Upgrade disruptor to include the fix for SleepingWaitStrategy causing 100%
   CPU.

 ## 0.12.1 - 2018-02-26
 - Fix performance issue where unused objects were referenced by the Disruptor.
 - Fix synchonization issue in the use of the Disruptor.

 ## 0.12.0 - 2018-02-16
 - Rename trace exporters that have inconsistent naming. Exporters with legacy
   names are deprecated.
 - Fixed bug in CloudTraceFormat that made it impossible to use short span id's.
 - Add `since` Javadoc tag to all APIs.
 - Add a configuration class to create StackdriverTraceExporter.
 - Add MessageEvent and deprecate NetworkEvent.
 - Instana Trace Exporter.
 - Prometheus Stats Exporter.
 - Stats Zpages: RpcZ and StatsZ.
 - Dependency updates.

 ## 0.11.1 - 2018-01-23
 - Fixed bug that made it impossible to use short span id's (#950).

 ## 0.11.0 - 2018-01-19
 - Add TextFormat API and two implementations (B3Format and CloudTraceFormat).
 - Add helper class to configure and create StackdriverStatsExporter.
 - Add helper methods in tracer to wrap Runnable and Callbacks and to run them.
 - Increase trace exporting interval to 5s.
 - Add helper class to register views.
 - Make stackdriver stats exporter compatible with GAE Java7.
 - Add SignalFX stats exporter.
 - Add http propagation APIs.
 - Dependency updates.

 ## 0.10.0 - 2017-12-04
 - Add NoopRunningSpanStore and NoopSampledSpanStore.
 - Change the message event to include (un)compressed sizes for Tracez Zpage.
 - Use AppEngine compatible way to create threads.
 - Add new factory methods that support setting custom Stackdriver
   MonitoredResource for Stackdriver Stats Exporter.
 - Dependency updates.

 ## 0.9.1 - 2017-11-29
 - Fix several implementation bugs in Stackdriver Stats Exporter (#830, #831,
   etc.).
 - Update length limit for View.Name to 255 (previously it's 256).

 ## 0.9.0 - 2017-11-17
 - Initial stats and tagging implementation for Java (`impl`) and Android
   (`impl-lite`). This implements all the stats and tagging APIs since v0.8.0.
 - Deprecate Tags.setState and Stats.setState.
 - Add a setStatus method in the Span.
 - OpenCensus Stackdriver Stats Exporter.
 - OpenCensus Stackdriver Trace Exporter is updated to use Stackdriver Trace V2
   APIs.
 - Dependency updates.
	## Unreleased

	- fix: Shutdown `MetricServiceClient` properly on `StackdriverStatsExporter.unregister()` (#2007)

	## 0.28.3 - 2021-01-12

	- fix: Return public access to unsafe `ContextUtils` api. Remove bincompat issue from 0.27.1. (#2072)
	- fix: When time rewinds, avoid throwing exceptions and crashing the disruptor thread. (#2071)

	## 0.28.2 - 2020-10-22

	- feat: Make TracerImpl public for OpenTelemetry migration. (#2064)

	Note: no binary available for 0.28.2

	## 0.28.1 - 2020-10-21

	- feat: Add Support for Opencensus to OpenTelemetry migration (#2059)

	Breaking change: ContextUtils is no longer public

	## 0.28.0 - 2020-10-21

	- Remove finalize from RecordEventsSpanImpl (#2043)

	## 0.27.0 - 2020-08-14
	- deps: update protobuf (#2029)
	- Update release versions for all readme and build files. (#2028)
	- deps: update Guava to 29.0 (#2032)
	- Add more InstanaExporterHandler tests (#2014)
	- feat: Allow users to specify a metric display name prefix, separately from the metric name prefix (#2050)

	## 0.26.0 - 2020-03-19
	- feat: Allow users to register the same Meter multiple times without exception (#2017)
	- update gRPC (#2024): Since gRPC v1.27.0, census dependency is removed from grpc-core. A grpc-census
	artifact now exists to provide interceptor/stream tracer factory that applies census stats/tracing features.
	For users not using gRPC’s integration of census, nothing should be affected. Users who want census integration
	need to add grpc-census artifact to runtime classpath.
	- deps: update GSON (#2025)
	- deps: update auth libraries (#2023)
	- update guava (#2018)

	## 0.25.0 - 2020-02-12
	- Add an experimental artifact `opencensus-contrib-observability-ready-util`, that allows users to
	use OpenCensus easily.

	## 0.24.0 - 2019-08-27
	- Remove `CONTEXT_SPAN_KEY` and `TAG_CONTEXT_KEY` from API. This will be a breaking change to those who
	depend on these two keys, but anyone except gRPC shouldn't use it directly anyway.

	## 0.23.0 - 2019-06-12
	- Make `StackdriverStatsExporter.unregister()` a public API.
	- Add support spring plugin for http servlet and AsyncRestTemplate.

	## 0.22.1 - 2019-05-21
	- Increase the buffer size for the trace export batch to 2500 (previously it was 32).

	## 0.22.0 - 2019-05-14
	- Disable RunningSpanStore by default unless the z-pages contrib is linked and initialized. This may
	break behaviors for applications that rely on this to be always enabled.
	- Provide a `Deadline` option to Stackdriver Trace exporter. Default value is 10 seconds if it's not set.
	- Provide a `Deadline` option to Stackdriver Stats exporter. Default value is 10 seconds.
	Also provide a `MetricServiceStub` option so that advanced users can use a custom Stackdriver
	Monitoring client to make RPCs.
	- Use `Configuration` builder pattern for creating `JaegerTraceExporter`, `ZipkinTraceExporter` and
	`InstanaTraceExporter`. Provide a `Deadline` option with default value 10 seconds.
	- Provide a `Deadline` option to Datadog, Elasticsearch and OcAgent exporter. Default value is 10 seconds.
	- Extract the common timeout logic of Trace exporters to `opencensus-exporter-trace-util`.

	## 0.21.0 - 2019-04-30
	- Add HTTP text format serializer to Tag propagation component.
	- Support constant labels in Gauge APIs.
	- Add an option to allow users to override the default "opencensus_task" metric label in Stackdriver Stats Exporter.
	- Allow setting custom namespace in Prometheus exporter.
	- Add Cumulative (`DoubleCumulative`, `LongCumulative`, `DerivedDoubleCumulative`, `DerivedLongCumulative`) APIs.
	- Add convenience APIs `TagContextBuilder.putLocal()` that adds non-propagating tags,
	and `TagContextBuilder.putPropagating()` that adds unlimited propagating tags.
	- Deprecate context keys for tags and spans. Provide helper methods for interacting with context.

	## 0.20.0 - 2019-03-28
	- Add OpenCensus Java OC-Agent Trace Exporter.
	- Add OpenCensus Java OC-Agent Metrics Exporter.
	- Add config option for Http-Servlet.
	- Add config option for Jetty Http Client.
	- Modified default value to false for publicEndpoint property in Http-Servlet.
	- Add a generic `AttachmentValue` class to support `Exemplar`.
	- Add Elasticsearch Trace Exporter.
	- Add `metrics.data` package to hold common classes shared between stats and metrics.
	- Refactor `Exemplar` and `AttachmentValue` to be under `metrics.data`. Note that this is a breaking change
	if you're using the `Exemplar` classes or APIs in the previous releases.
	- Add `TagMetadata` that defines the properties associated with a `Tag`.
	- Add `QueueMetricProducer` that supports pushing and buffering `Metric`s.

	## 0.19.0 - 2019-01-28
	- Add an artifact `opencensus-contrib-http-jetty-client` for instrumenting jetty http client. Add extractor for Jetty Client.
	- Add an artifact `opencensus-contrib-http-servlets` for instrumenting http servlets. Add extractor for Http Servlets.
	- Add support generic http server handler.
	- Add support for generic http client handler.
	- Add ability to filter metrics collected from Dropwizard registry.
	- Add an util artifact opencensus-contrib-dropwizard5 to translate Dropwizard metrics5 to OpenCensus.
	- Add metrics util package to be shared by all metrics exporters.
	- Add Datadog Trace Exporter.

	## 0.18.0 - 2018-11-27
	- Set the
	[`trace_sampled` field](https://github.com/googleapis/googleapis/blob/8027f17420d5a323c7dfef1ae0e57d82f3b97430/google/logging/v2/log_entry.proto#L143-L149) in the Stackdriver `LogEntry` protocol buffer in `opencensus-contrib-log-correlation-stackdriver`.
	- Add support for w3c/distributed-tracing propagation format.
	- Add gRPC measures and views for real-time metrics in streaming RPCs.
	- Add Summary Metric support for Stackdriver exporter.
	- Reduce CPU usage for low qps applications.

	## 0.17.0 - 2018-11-02
	- Add `AttributeValueDouble` to `AttributeValue`.
	- Add `createWithSender` to `JaegerTraceExporter` to allow use of `HttpSender`
	with extra configurations.
	- Add an API `Functions.returnToString()`.
	- Migrate to new Stackdriver Kubernetes monitored resource. This could be a breaking change
	if you are using `gke_container` resources. For more info,
	https://cloud.google.com/monitoring/kubernetes-engine/migration#incompatible
	- Add an util artifact `opencensus-contrib-dropwizard` to translate Dropwizard metrics to
	OpenCensus.
	- Add Gauges (`DoubleGauge`, `LongGauge`, `DerivedDoubleGauge`, `DerivedLongGauge`) APIs.
	- Update `opencensus-contrib-log-correlation-log4j2` and
	`opencensus-contrib-log-correlation-stackdriver` to match the
	[OpenCensus log correlation spec](https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/LogCorrelation.md)
	and remove all `ExperimentalApi` annotations.
	- The histogram bucket boundaries (`BucketBoundaries`) and values (`Count` and `Sum`) are no longer
	supported for negative values. The Record API drops the negative `value` and logs the warning.
	This could be a breaking change if you are recording negative value for any `measure`.
	- Remove support for min/max in the stats Distribution to make it compatible with Metrics.

	## 0.16.1 - 2018-09-18
	- Fix ClassCastException in Log4j log correlation
	([#1436](https://github.com/census-instrumentation/opencensus-java/issues/1436)).
	- Allow users to report metrics for their registered domain (using custom prefix). This could be a
	breaking change if you have custom prefix without (registered) domain.

	## 0.16.0 - 2018-09-14
	- Add APIs to register gRPC client and server views separately.
	- Add an API MeasureMap.putAttachment() for recording exemplars.
	- Add Exemplar class and an API to get Exemplar list to DistributionData.
	- Improve the styling of Rpcz, Statsz, Tracez, and Traceconfigz pages.
	- Add an artifact `opencensus-contrib-exemplar-util` that has helper utilities
	on recording exemplars.
	- Reduce the default limit on `Link`s per `Span` to 32 (was 128 before).
	- Add Spring support for `@Traced` annotation and java.sql.PreparedStatements
	tracing.
	- Allow custom prefix for Stackdriver metrics in `StackdriverStatsConfiguration`.
	- Add support to handle the Tracestate in the SpanContext.
	- Remove global synchronization from the get current stats state.
	- Add get/from{Byte} methods on TraceOptions and deprecate get/from{Bytes}.
	- Add an API to `StackdriverTraceConfiguration` to allow setting a
	`TraceServiceStub` instance to be used for export RPC calls.
	- Add an experimental artifact, `opencensus-contrib-log-correlation-log4j2`, for
	adding tracing data to Log4j 2 LogEvents.

	## 0.15.1 - 2018-08-28
	- Improve propagation performance by avoiding doing string formatting when calling checkArgument.

	## 0.15.0 - 2018-06-20
	- Expose the factory methods of MonitoredResource.
	- Add an experimental artifact, `opencensus-contrib-log-correlation-stackdriver`, for
	correlating traces and logs with Stackdriver Logging.

	## 0.14.0 - 2018-06-04
	- Adds Tracing.getExportComponent().shutdown() for use within application shutdown hooks.
	- `Duration.create` now throws an `IllegalArgumentException` instead of
	returning a zero `Duration` when the arguments are invalid.
	- `Timestamp.create` now throws an `IllegalArgumentException` instead of
	returning a zero `Timestamp` when the arguments are invalid.
	- Remove namespace and help message prefix for Prometheus exporter. This could be
	a breaking change if you have Prometheus metrics from OpenCensus Prometheus exporter
	of previous versions, please point to the new metrics with no namespace instead.
	- Add an util artifact `opencensus-contrib-appengine-standard-util` to interact with the AppEngine
	CloudTraceContext.
	- Add support for Span kinds. (fix [#1054](https://github.com/census-instrumentation/opencensus-java/issues/1054)).
	- Add client/server started_rpcs measures and views to RPC constants.

	## 0.13.2 - 2018-05-08
	- Map http attributes to Stackdriver format (fix [#1153](https://github.com/census-instrumentation/opencensus-java/issues/1153)).

	## 0.13.1 - 2018-05-02
	- Fix a typo on displaying Aggregation Type for a View on StatsZ page.
	- Set bucket bounds as "le" labels for Prometheus Stats exporter.

	## 0.13.0 - 2018-04-27
	- Support building with Java 9.
	- Add a QuickStart example.
	- Remove extraneous dependencies from the Agent's `pom.xml`.
	- Deprecate `Window` and `WindowData`.
	- Add a configuration class to the Prometheus stats exporter.
	- Fix build on platforms that are not supported by `netty-tcnative`.
	- Add Jaeger trace exporter.
	- Add a gRPC Hello World example.
	- Remove usages of Guava collections in `opencensus-api`.
	- Set unit "1" when the aggregation type is Count.
	- Auto detect GCE and GKE Stackdriver MonitoredResources.
	- Make Error Prone and FindBugs annotations `compileOnly` dependencies.
	- Deprecate `Mean` and `MeanData`.
	- Sort `TagKey`s in `View.create(...)`.
	- Add utility class to expose default HTTP measures, tags and view, and register
	default views.
	- Add new RPC measure and view constants, deprecate old ones.
	- Makes the trace and span ID fields mandatory in binary format.
	- Auto detect AWS EC2 resources.
	- Add `Duration.toMillis()`.
	- Make monitored resource utils a separate artifact `opencensus-contrib-monitored-resource-util`,
	so that it can be reused across exporters.
	- Add `LastValue`, `LastValueDouble` and `LastValueLong`. Also support them in
	stats exporters and zpages. Please note that there is an API breaking change
	in methods `Aggregation.match()` and `AggregationData.match()`.

	## 0.12.3 - 2018-04-13
	- Substitute non-ascii characters in B3Format header key.

	## 0.12.2 - 2018-02-26
	- Upgrade disruptor to include the fix for SleepingWaitStrategy causing 100%
	CPU.

	## 0.12.1 - 2018-02-26
	- Fix performance issue where unused objects were referenced by the Disruptor.
	- Fix synchonization issue in the use of the Disruptor.

	## 0.12.0 - 2018-02-16
	- Rename trace exporters that have inconsistent naming. Exporters with legacy
	names are deprecated.
	- Fixed bug in CloudTraceFormat that made it impossible to use short span id's.
	- Add `since` Javadoc tag to all APIs.
	- Add a configuration class to create StackdriverTraceExporter.
	- Add MessageEvent and deprecate NetworkEvent.
	- Instana Trace Exporter.
	- Prometheus Stats Exporter.
	- Stats Zpages: RpcZ and StatsZ.
	- Dependency updates.

	## 0.11.1 - 2018-01-23
	- Fixed bug that made it impossible to use short span id's (#950).

	## 0.11.0 - 2018-01-19
	- Add TextFormat API and two implementations (B3Format and CloudTraceFormat).
	- Add helper class to configure and create StackdriverStatsExporter.
	- Add helper methods in tracer to wrap Runnable and Callbacks and to run them.
	- Increase trace exporting interval to 5s.
	- Add helper class to register views.
	- Make stackdriver stats exporter compatible with GAE Java7.
	- Add SignalFX stats exporter.
	- Add http propagation APIs.
	- Dependency updates.

	## 0.10.0 - 2017-12-04
	- Add NoopRunningSpanStore and NoopSampledSpanStore.
	- Change the message event to include (un)compressed sizes for Tracez Zpage.
	- Use AppEngine compatible way to create threads.
	- Add new factory methods that support setting custom Stackdriver
	MonitoredResource for Stackdriver Stats Exporter.
	- Dependency updates.

	## 0.9.1 - 2017-11-29
	- Fix several implementation bugs in Stackdriver Stats Exporter (#830, #831,
	etc.).
	- Update length limit for View.Name to 255 (previously it's 256).

	## 0.9.0 - 2017-11-17
	- Initial stats and tagging implementation for Java (`impl`) and Android
	(`impl-lite`). This implements all the stats and tagging APIs since v0.8.0.
	- Deprecate Tags.setState and Stats.setState.
	- Add a setStatus method in the Span.
	- OpenCensus Stackdriver Stats Exporter.
	- OpenCensus Stackdriver Trace Exporter is updated to use Stackdriver Trace V2
	APIs.
	- Dependency updates.