From 35e926b9c6168f3e34670b2ec01b4cf900546c20 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 3 Aug 2022 14:01:28 +0300
Subject: [PATCH 1/3] Split project into modules

---
 .github/workflows/ci.yml                      |   4 +-
 build.sbt                                     | 131 +++++++---
 .../scala/org/typelevel/otel4s/Otel4s.scala   |   2 +-
 .../org/typelevel/otel4s/Attribute.scala      |   0
 .../org/typelevel/otel4s/AttributeKey.scala   |   0
 .../org/typelevel/otel4s/AttributeType.scala  |   0
 .../otel4s/meta/InstrumentMeta.scala          |  47 ++++
 .../otel4s/meta/InstrumentMetaSuite.scala}    |  25 +-
 .../otel4s/metrics/CounterMacro.scala         |  31 ++-
 .../otel4s/metrics/HistogramMacro.scala       |  31 ++-
 .../otel4s/metrics/UpDownCounterMacro.scala   |  42 +++-
 .../otel4s/metrics/CounterMacro.scala         |  28 ++-
 .../otel4s/metrics/HistogramMacro.scala       |  30 ++-
 .../otel4s/metrics/UpDownCounterMacro.scala   |  39 ++-
 .../typelevel/otel4s/metrics/Counter.scala    |  19 +-
 .../typelevel/otel4s/metrics/Histogram.scala  |  29 ++-
 .../org/typelevel/otel4s/metrics/Meter.scala  |   0
 .../otel4s/metrics/MeterBuilder.scala         |   0
 .../otel4s/metrics/MeterProvider.scala        |   0
 .../otel4s/metrics/ObservableCounter.scala    |   0
 .../otel4s/metrics/ObservableGauge.scala      |   0
 .../metrics/ObservableInstrumentBuilder.scala |   0
 .../metrics/ObservableUpDownCounter.scala     |   0
 .../metrics/SyncInstrumentBuilder.scala       |   0
 .../otel4s/metrics/UpDownCounter.scala        |  21 +-
 .../otel4s/metrics/CounterSuite.scala         |   3 +-
 .../otel4s/metrics/HistogramSuite.scala       |   2 +-
 .../otel4s/metrics/UpDownCounterSuite.scala   |   3 +-
 .../otel4s/metrics/MetricsMacro.scala         |  73 ------
 .../otel4s/metrics/MetricsMacro.scala         |  95 --------
 .../org/typelevel/otel4s/java/OtelJava.scala  |  33 +++
 .../typelevel/otel4s/java/Conversions.scala   |  74 ++++++
 .../org/typelevel/otel4s/java/Metrics.scala   |  35 +++
 .../java/metrics/CounterBuilderImpl.scala     |  45 ++++
 .../otel4s/java/metrics/CounterImpl.scala     |  39 +++
 .../java/metrics/HistogramBuilderImpl.scala   |  45 ++++
 .../otel4s/java/metrics/HistogramImpl.scala   |  39 +++
 .../java/metrics/MeterBuilderImpl.scala       |  44 ++++
 .../otel4s/java/metrics/MeterImpl.scala       |  38 +++
 .../java/metrics/MeterProviderImpl.scala      |  32 +++
 .../metrics/UpDownCounterBuilderImpl.scala    |  46 ++++
 .../java/metrics/UpDownCounterImpl.scala      |  39 +++
 .../otel4s/java/metrics/CounterSuite.scala}   |  15 +-
 .../org/typelevel/otel4s/java/impl.scala      | 226 ------------------
 java/src/test/scala/com/example/PoC.scala     |  63 -----
 .../typelevel/otel4s/testkit/Implicits.scala  |   0
 .../testkit/InstrumentationResource.scala}    |  20 +-
 .../otel4s/testkit/InstrumentationScope.scala |   0
 .../otel4s/testkit/metrics/MetricsSdk.scala}  |  11 +-
 .../testkit/metrics}/HistogramPointData.scala |   2 +-
 .../otel4s/testkit/metrics}/Metric.scala      |   3 +-
 .../otel4s/testkit/metrics}/MetricData.scala  |   2 +-
 .../otel4s/testkit/metrics}/PointData.scala   |   1 +
 .../testkit/metrics}/QuantileData.scala       |   2 +-
 .../testkit/metrics}/SummaryPointData.scala   |   2 +-
 55 files changed, 945 insertions(+), 566 deletions(-)
 rename core/{ => all}/src/main/scala/org/typelevel/otel4s/Otel4s.scala (90%)
 rename core/{ => common}/src/main/scala/org/typelevel/otel4s/Attribute.scala (100%)
 rename core/{ => common}/src/main/scala/org/typelevel/otel4s/AttributeKey.scala (100%)
 rename core/{ => common}/src/main/scala/org/typelevel/otel4s/AttributeType.scala (100%)
 create mode 100644 core/common/src/main/scala/org/typelevel/otel4s/meta/InstrumentMeta.scala
 rename core/{src/main/scala/org/typelevel/otel4s/metrics/InstrumentBackend.scala => common/src/test/scala/org/typelevel/otel4s/meta/InstrumentMetaSuite.scala} (58%)
 rename core/{ => metrics}/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala (63%)
 rename core/{ => metrics}/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala (68%)
 rename core/{ => metrics}/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala (57%)
 rename core/{ => metrics}/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala (65%)
 rename core/{ => metrics}/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala (69%)
 rename core/{ => metrics}/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala (58%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala (82%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala (84%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/Meter.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/MeterBuilder.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/MeterProvider.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/ObservableCounter.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/ObservableGauge.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/ObservableInstrumentBuilder.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/ObservableUpDownCounter.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/SyncInstrumentBuilder.scala (100%)
 rename core/{ => metrics}/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala (83%)
 rename core/{ => metrics}/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala (96%)
 rename core/{ => metrics}/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala (98%)
 rename core/{ => metrics}/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala (96%)
 delete mode 100644 core/src/main/scala-2/org/typelevel/otel4s/metrics/MetricsMacro.scala
 delete mode 100644 core/src/main/scala-3/org/typelevel/otel4s/metrics/MetricsMacro.scala
 create mode 100644 java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
 create mode 100644 java/common/src/main/scala/org/typelevel/otel4s/java/Conversions.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
 create mode 100644 java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
 rename java/{src/test/scala/org/typelevel/otel4s/java/JavaOtelSuite.scala => metrics/src/test/scala/org/typelevel/otel4s/java/metrics/CounterSuite.scala} (89%)
 delete mode 100644 java/src/main/scala/org/typelevel/otel4s/java/impl.scala
 delete mode 100644 java/src/test/scala/com/example/PoC.scala
 rename testkit/{ => common}/shared/src/main/scala/org/typelevel/otel4s/testkit/Implicits.scala (100%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit/MetricResource.scala => common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationResource.scala} (67%)
 rename testkit/{ => common}/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationScope.scala (100%)
 rename testkit/{jvm/src/main/scala/org/typelevel/otel4s/testkit/Sdk.scala => metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala} (97%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/HistogramPointData.scala (97%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/Metric.scala (96%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/MetricData.scala (98%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/PointData.scala (98%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/QuantileData.scala (96%)
 rename testkit/{shared/src/main/scala/org/typelevel/otel4s/testkit => metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics}/SummaryPointData.scala (96%)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f05852f47..2a26a224f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -94,11 +94,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target java/.jvm/target testkit/jvm/target project/target
+        run: mkdir -p testkit/metrics/jvm/target testkit/common/jvm/target target java/common/.jvm/target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target java/metrics/.jvm/target core/all/.js/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target java/all/.jvm/target testkit/all/jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target java/.jvm/target testkit/jvm/target project/target
+        run: tar cf targets.tar testkit/metrics/jvm/target testkit/common/jvm/target target java/common/.jvm/target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target java/metrics/.jvm/target core/all/.js/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target java/all/.jvm/target testkit/all/jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
diff --git a/build.sbt b/build.sbt
index aa502b320..1f04f66c1 100644
--- a/build.sbt
+++ b/build.sbt
@@ -21,57 +21,130 @@ val Scala213 = "2.13.8"
 ThisBuild / crossScalaVersions := Seq(Scala213, "3.1.3")
 ThisBuild / scalaVersion := Scala213 // the default Scala
 
+val CatsVersion = "2.8.0"
+val CatsEffectVersion = "3.3.13"
+val MUnitVersion = "0.7.29"
+val MUnitCatsEffectVersion = "1.0.7"
+val OpenTelemetryVersion = "1.15.0"
+
+lazy val scalaReflectDependency = Def.settings(
+  libraryDependencies ++= {
+    if (tlIsScala3.value) Nil
+    else Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided)
+  }
+)
+
 lazy val root = tlCrossRootProject
-  .aggregate(core, testkit, java)
+  .aggregate(
+    `core-common`,
+    `core-metrics`,
+    core,
+    `testkit-common`,
+    `testkit-metrics`,
+    testkit,
+    `java-common`,
+    `java-metrics`,
+    java
+  )
   .settings(name := "otel4s")
 
+lazy val `core-common` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("core/common"))
+  .settings(
+    name := "otel4s-core-common",
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "cats-core" % CatsVersion,
+      "org.scalameta" %%% "munit" % MUnitVersion % Test
+    )
+  )
+
+lazy val `core-metrics` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("core/metrics"))
+  .dependsOn(`core-common`)
+  .settings(scalaReflectDependency)
+  .settings(
+    name := "otel4s-core-metrics",
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "cats-effect" % CatsEffectVersion,
+      "org.scalameta" %%% "munit" % MUnitVersion % Test,
+      "org.typelevel" %%% "munit-cats-effect-3" % MUnitCatsEffectVersion % Test,
+      "org.typelevel" %%% "cats-effect-testkit" % CatsEffectVersion % Test
+    )
+  )
+
 lazy val core = crossProject(JVMPlatform, JSPlatform)
   .crossType(CrossType.Pure)
-  .in(file("core"))
+  .in(file("core/all"))
+  .dependsOn(`core-common`, `core-metrics`)
   .settings(
-    name := "otel4s-core",
+    name := "otel4s-core"
+  )
+
+lazy val `testkit-common` = crossProject(JVMPlatform)
+  .crossType(CrossType.Full)
+  .in(file("testkit/common"))
+  .dependsOn(`core-common`)
+  .settings(
+    name := "otel4s-testkit-common"
+  )
+
+lazy val `testkit-metrics` = crossProject(JVMPlatform)
+  .crossType(CrossType.Full)
+  .in(file("testkit/metrics"))
+  .dependsOn(`testkit-common`, `core-metrics`)
+  .settings(
+    name := "otel4s-testkit-metrics"
+  )
+  .jvmSettings(
     libraryDependencies ++= Seq(
-      "org.typelevel" %%% "cats-core" % "2.8.0",
-      "org.typelevel" %%% "cats-effect" % "3.3.13",
-      "org.scalameta" %%% "munit" % "0.7.29" % Test,
-      "org.typelevel" %%% "munit-cats-effect-3" % "1.0.7" % Test,
-      "org.typelevel" %%% "cats-effect-testkit" % "3.3.13" % Test
-    ),
-    libraryDependencies ++= {
-      if (tlIsScala3.value) Nil
-      else
-        Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided)
-    }
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk-testing" % OpenTelemetryVersion
+    )
   )
 
 lazy val testkit = crossProject(JVMPlatform)
   .crossType(CrossType.Full)
-  .in(file("testkit"))
+  .in(file("testkit/all"))
+  .dependsOn(`testkit-common`, `testkit-metrics`)
   .settings(
     name := "otel4s-testkit"
   )
-  .jvmSettings(
+
+lazy val `java-common` = crossProject(JVMPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("java/common"))
+  .dependsOn(`core-common`, `testkit-common`)
+  .settings(
+    name := "otel4s-java-common",
     libraryDependencies ++= Seq(
-      "io.opentelemetry" % "opentelemetry-api" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.15.0"
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion
     )
   )
-  .dependsOn(core)
 
-lazy val java = crossProject(JVMPlatform)
+lazy val `java-metrics` = crossProject(JVMPlatform)
   .crossType(CrossType.Pure)
-  .in(file("java"))
+  .in(file("java/metrics"))
+  .dependsOn(`java-common`, `core-metrics`, `testkit-metrics`)
   .settings(
-    name := "otel4s-java",
+    name := "otel4s-java-metrics",
     libraryDependencies ++= Seq(
-      "io.opentelemetry" % "opentelemetry-api" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk" % "1.15.0" % Test,
-      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.15.0" % Test,
-      "org.scalameta" %% "munit" % "0.7.29" % Test,
-      "org.typelevel" %% "munit-cats-effect-3" % "1.0.7" % Test
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk" % OpenTelemetryVersion % Test,
+      "io.opentelemetry" % "opentelemetry-sdk-testing" % OpenTelemetryVersion % Test,
+      "org.scalameta" %% "munit" % MUnitVersion % Test,
+      "org.typelevel" %% "munit-cats-effect-3" % MUnitCatsEffectVersion % Test
     )
   )
-  .dependsOn(core, testkit)
+
+lazy val java = crossProject(JVMPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("java/all"))
+  .dependsOn(core, `java-metrics`)
+  .settings(
+    name := "otel4s-java"
+  )
 
 lazy val docs = project.in(file("site")).enablePlugins(TypelevelSitePlugin)
diff --git a/core/src/main/scala/org/typelevel/otel4s/Otel4s.scala b/core/all/src/main/scala/org/typelevel/otel4s/Otel4s.scala
similarity index 90%
rename from core/src/main/scala/org/typelevel/otel4s/Otel4s.scala
rename to core/all/src/main/scala/org/typelevel/otel4s/Otel4s.scala
index 3d1a14beb..0a5c8a069 100644
--- a/core/src/main/scala/org/typelevel/otel4s/Otel4s.scala
+++ b/core/all/src/main/scala/org/typelevel/otel4s/Otel4s.scala
@@ -20,7 +20,7 @@ import org.typelevel.otel4s.metrics.MeterProvider
 
 trait Otel4s[F[_]] {
 
-  /** A registry for creating named [[org.typelevel.otel4s.metrics.Meter]].
+  /** A registry for creating named meters.
     */
   def meterProvider: MeterProvider[F]
 }
diff --git a/core/src/main/scala/org/typelevel/otel4s/Attribute.scala b/core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/Attribute.scala
rename to core/common/src/main/scala/org/typelevel/otel4s/Attribute.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/AttributeKey.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
rename to core/common/src/main/scala/org/typelevel/otel4s/AttributeKey.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/AttributeType.scala b/core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/AttributeType.scala
rename to core/common/src/main/scala/org/typelevel/otel4s/AttributeType.scala
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/meta/InstrumentMeta.scala b/core/common/src/main/scala/org/typelevel/otel4s/meta/InstrumentMeta.scala
new file mode 100644
index 000000000..946d13076
--- /dev/null
+++ b/core/common/src/main/scala/org/typelevel/otel4s/meta/InstrumentMeta.scala
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.meta
+
+import cats.Applicative
+
+trait InstrumentMeta[F[_]] {
+
+  /** Indicates whether instrumentation is enabled or not.
+    */
+  def isEnabled: Boolean
+
+  /** A no-op effect.
+    */
+  def unit: F[Unit]
+
+}
+
+object InstrumentMeta {
+
+  def enabled[F[_]: Applicative]: InstrumentMeta[F] =
+    make(enabled = true)
+
+  def disabled[F[_]: Applicative]: InstrumentMeta[F] =
+    make(enabled = false)
+
+  private def make[F[_]: Applicative](enabled: Boolean): InstrumentMeta[F] =
+    new InstrumentMeta[F] {
+      val isEnabled: Boolean = enabled
+      val unit: F[Unit] = Applicative[F].unit
+    }
+
+}
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/InstrumentBackend.scala b/core/common/src/test/scala/org/typelevel/otel4s/meta/InstrumentMetaSuite.scala
similarity index 58%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/InstrumentBackend.scala
rename to core/common/src/test/scala/org/typelevel/otel4s/meta/InstrumentMetaSuite.scala
index 4a5c35a6b..38766f157 100644
--- a/core/src/main/scala/org/typelevel/otel4s/metrics/InstrumentBackend.scala
+++ b/core/common/src/test/scala/org/typelevel/otel4s/meta/InstrumentMetaSuite.scala
@@ -14,11 +14,24 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.metrics
+package org.typelevel.otel4s.meta
+
+import munit.FunSuite
+
+class InstrumentMetaSuite extends FunSuite {
+
+  test("enabled") {
+    val disabled = InstrumentMeta.enabled[cats.Id]
+
+    assertEquals(disabled.unit, ())
+    assertEquals(disabled.isEnabled, true)
+  }
+
+  test("disabled") {
+    val disabled = InstrumentMeta.disabled[cats.Id]
+
+    assertEquals(disabled.unit, ())
+    assertEquals(disabled.isEnabled, false)
+  }
 
-/** A backend that implements instrument operations: add, record, etc.
-  */
-trait InstrumentBackend[F[_]] {
-  def isEnabled: Boolean
-  def unit: F[Unit]
 }
diff --git a/core/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala
similarity index 63%
rename from core/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala
rename to core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala
index 7c80f00db..821c6340e 100644
--- a/core/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala
+++ b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala
@@ -29,7 +29,7 @@ private[otel4s] trait CounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def add(value: A, attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.add[A]
+    macro CounterMacro.add[A]
 
   /** Increments a counter by one.
     *
@@ -37,5 +37,32 @@ private[otel4s] trait CounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def inc(attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.inc
+    macro CounterMacro.inc
+
+}
+
+object CounterMacro {
+  import scala.reflect.macros.blackbox
+
+  def add[A](c: blackbox.Context)(
+      value: c.Expr[A],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.add($value, ..$attributes) else $meta.unit"
+  }
+
+  def inc(c: blackbox.Context)(
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.inc(..$attributes) else $meta.unit"
+  }
+
 }
diff --git a/core/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
similarity index 68%
rename from core/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
rename to core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
index f0d731821..e40346866 100644
--- a/core/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
+++ b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
@@ -33,7 +33,7 @@ private[otel4s] trait HistogramMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def record(value: A, attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.record[A]
+    macro HistogramMacro.record[A]
 
   /** Records duration of the given effect.
     *
@@ -58,6 +58,33 @@ private[otel4s] trait HistogramMacro[F[_], A] {
       timeUnit: TimeUnit,
       attributes: Attribute[_]*
   ): Resource[F, Unit] =
-    macro MetricsMacro.recordDuration
+    macro HistogramMacro.recordDuration
+
+}
+
+object HistogramMacro {
+  import scala.reflect.macros.blackbox
+
+  def record[A](c: blackbox.Context)(
+      value: c.Expr[A],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.record($value, ..$attributes) else $meta.unit"
+  }
+
+  def recordDuration(c: blackbox.Context)(
+      timeUnit: c.Expr[TimeUnit],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.recordDuration($timeUnit, ..$attributes) else $meta.resourceUnit"
+  }
 
 }
diff --git a/core/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
similarity index 57%
rename from core/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
rename to core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
index e8335b6f3..2879f4cfe 100644
--- a/core/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
+++ b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
@@ -29,7 +29,7 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def add(value: A, attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.add[A]
+    macro UpDownCounterMacro.add[A]
 
   /** Increments a counter by one.
     *
@@ -37,7 +37,7 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def inc(attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.inc
+    macro UpDownCounterMacro.inc
 
   /** Decrements a counter by one.
     *
@@ -45,6 +45,42 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def dec(attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.dec
+    macro UpDownCounterMacro.dec
+
+}
+
+object UpDownCounterMacro {
+  import scala.reflect.macros.blackbox
+
+  def add[A](c: blackbox.Context)(
+      value: c.Expr[A],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.add($value, ..$attributes) else $meta.unit"
+  }
+
+  def inc(c: blackbox.Context)(
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.inc(..$attributes) else $meta.unit"
+  }
+
+  def dec(c: blackbox.Context)(
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.dec(..$attributes) else $meta.unit"
+  }
 
 }
diff --git a/core/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala
similarity index 65%
rename from core/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala
rename to core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala
index 8bb2c6c88..a1857eccd 100644
--- a/core/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala
+++ b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/CounterMacro.scala
@@ -31,7 +31,7 @@ private[otel4s] trait CounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   inline def add(inline value: A, inline attributes: Attribute[_]*): F[Unit] =
-    ${ MetricsMacro.counter.add('backend, 'value, 'attributes) }
+    ${ CounterMacro.add('backend, 'value, 'attributes) }
 
   /** Increments a counter by one.
     *
@@ -39,5 +39,29 @@ private[otel4s] trait CounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   inline def inc(inline attributes: Attribute[_]*): F[Unit] =
-    ${ MetricsMacro.counter.inc('backend, 'attributes) }
+    ${ CounterMacro.inc('backend, 'attributes) }
+
+}
+
+object CounterMacro {
+
+  def add[F[_], A](
+      backend: Expr[Counter.Backend[F, A]],
+      value: Expr[A],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.add($value, $attributes*)
+      else $backend.meta.unit
+    }
+
+  def inc[F[_], A](
+      backend: Expr[Counter.Backend[F, A]],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.inc($attributes*)
+      else $backend.meta.unit
+    }
+
 }
diff --git a/core/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
similarity index 69%
rename from core/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
rename to core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
index 52e363a03..ad964d627 100644
--- a/core/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
+++ b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
@@ -37,7 +37,7 @@ private[otel4s] trait HistogramMacro[F[_], A] {
       inline value: A,
       inline attributes: Attribute[_]*
   ): F[Unit] =
-    ${ MetricsMacro.histogram.record('backend, 'value, 'attributes) }
+    ${ HistogramMacro.record('backend, 'value, 'attributes) }
 
   /** Records duration of the given effect.
     *
@@ -62,5 +62,31 @@ private[otel4s] trait HistogramMacro[F[_], A] {
       inline timeUnit: TimeUnit,
       inline attributes: Attribute[_]*
   ): Resource[F, Unit] =
-    ${ MetricsMacro.histogram.recordDuration('backend, 'timeUnit, 'attributes) }
+    ${ HistogramMacro.recordDuration('backend, 'timeUnit, 'attributes) }
+
+}
+
+object HistogramMacro {
+
+  def record[F[_], A](
+      backend: Expr[Histogram.Backend[F, A]],
+      value: Expr[A],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.record($value, $attributes*)
+      else $backend.meta.unit
+    }
+
+  def recordDuration[F[_], A](
+      backend: Expr[Histogram.Backend[F, A]],
+      timeUnit: Expr[TimeUnit],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled)
+        $backend.recordDuration($timeUnit, $attributes*)
+      else $backend.meta.resourceUnit
+    }
+
 }
diff --git a/core/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
similarity index 58%
rename from core/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
rename to core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
index a20db17fe..b50b8260d 100644
--- a/core/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
+++ b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/UpDownCounterMacro.scala
@@ -31,7 +31,7 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   inline def add(inline value: A, inline attributes: Attribute[_]*): F[Unit] =
-    ${ MetricsMacro.upDownCounter.add('backend, 'value, 'attributes) }
+    ${ UpDownCounterMacro.add('backend, 'value, 'attributes) }
 
   /** Increments a counter by one.
     *
@@ -39,7 +39,7 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   inline def inc(inline attributes: Attribute[_]*): F[Unit] =
-    ${ MetricsMacro.upDownCounter.inc('backend, 'attributes) }
+    ${ UpDownCounterMacro.inc('backend, 'attributes) }
 
   /** Decrements a counter by one.
     *
@@ -47,5 +47,38 @@ private[otel4s] trait UpDownCounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   inline def dec(inline attributes: Attribute[_]*): F[Unit] =
-    ${ MetricsMacro.upDownCounter.dec('backend, 'attributes) }
+    ${ UpDownCounterMacro.dec('backend, 'attributes) }
+
+}
+
+object UpDownCounterMacro {
+
+  def add[F[_], A](
+      backend: Expr[UpDownCounter.Backend[F, A]],
+      value: Expr[A],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.add($value, $attributes*)
+      else $backend.meta.unit
+    }
+
+  def inc[F[_], A](
+      backend: Expr[UpDownCounter.Backend[F, A]],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.inc($attributes*)
+      else $backend.meta.unit
+    }
+
+  def dec[F[_], A](
+      backend: Expr[UpDownCounter.Backend[F, A]],
+      attributes: Expr[Seq[Attribute[_]]]
+  )(using Quotes, Type[F], Type[A]) =
+    '{
+      if ($backend.meta.isEnabled) $backend.dec($attributes*)
+      else $backend.meta.unit
+    }
+
 }
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala
similarity index 82%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala
index 9c2b11965..fd0f82b78 100644
--- a/core/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala
+++ b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Counter.scala
@@ -18,6 +18,7 @@ package org.typelevel.otel4s
 package metrics
 
 import cats.Applicative
+import org.typelevel.otel4s.meta.InstrumentMeta
 
 /** A `Counter` instrument that records values of type `A`.
   *
@@ -37,7 +38,8 @@ trait Counter[F[_], A] extends CounterMacro[F, A]
 
 object Counter {
 
-  trait Backend[F[_], A] extends InstrumentBackend[F] {
+  trait Backend[F[_], A] {
+    def meta: InstrumentMeta[F]
 
     /** Records a value with a set of attributes.
       *
@@ -57,16 +59,12 @@ object Counter {
     def inc(attributes: Attribute[_]*): F[Unit]
   }
 
-  abstract class LongBackend[F[_]: Applicative] extends Backend[F, Long] {
-    final val unit: F[Unit] = Applicative[F].unit
-
+  trait LongBackend[F[_]] extends Backend[F, Long] {
     final def inc(attributes: Attribute[_]*): F[Unit] =
       add(1L, attributes: _*)
   }
 
-  abstract class DoubleBackend[F[_]: Applicative] extends Backend[F, Double] {
-    final val unit: F[Unit] = Applicative[F].unit
-
+  trait DoubleBackend[F[_]] extends Backend[F, Double] {
     final def inc(attributes: Attribute[_]*): F[Unit] =
       add(1.0, attributes: _*)
   }
@@ -75,10 +73,9 @@ object Counter {
     new Counter[F, A] {
       val backend: Backend[F, A] =
         new Backend[F, A] {
-          val isEnabled: Boolean = false
-          val unit: F[Unit] = F.unit
-          def add(value: A, attributes: Attribute[_]*): F[Unit] = unit
-          def inc(attributes: Attribute[_]*): F[Unit] = unit
+          val meta: InstrumentMeta[F] = InstrumentMeta.disabled
+          def add(value: A, attributes: Attribute[_]*): F[Unit] = meta.unit
+          def inc(attributes: Attribute[_]*): F[Unit] = meta.unit
         }
     }
 
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
similarity index 84%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
index fbdd9ff65..ec7e97bfa 100644
--- a/core/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
+++ b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
@@ -23,6 +23,7 @@ import cats.effect.Clock
 import cats.effect.Resource
 import cats.syntax.flatMap._
 import cats.syntax.functor._
+import org.typelevel.otel4s.meta.InstrumentMeta
 
 import scala.concurrent.duration.TimeUnit
 
@@ -35,6 +36,7 @@ import scala.concurrent.duration.TimeUnit
   *
   * @tparam F
   *   the higher-kinded type of a polymorphic effect
+  *
   * @tparam A
   *   the type of the values to record. OpenTelemetry specification expects `A`
   *   to be either [[scala.Long]] or [[scala.Double]].
@@ -43,8 +45,24 @@ trait Histogram[F[_], A] extends HistogramMacro[F, A]
 
 object Histogram {
 
-  trait Backend[F[_], A] extends InstrumentBackend[F] {
-    final val resourceUnit: Resource[F, Unit] = Resource.unit
+  trait Meta[F[_]] extends InstrumentMeta[F] {
+    def resourceUnit: Resource[F, Unit]
+  }
+
+  object Meta {
+    def enabled[F[_]: Applicative]: Meta[F] = make(enabled = true)
+    def disabled[F[_]: Applicative]: Meta[F] = make(enabled = false)
+
+    private def make[F[_]: Applicative](enabled: Boolean): Meta[F] =
+      new Meta[F] {
+        val isEnabled: Boolean = enabled
+        val unit: F[Unit] = Applicative[F].unit
+        val resourceUnit: Resource[F, Unit] = Resource.unit
+      }
+  }
+
+  trait Backend[F[_], A] {
+    def meta: Meta[F]
 
     /** Records a value with a set of attributes.
       *
@@ -108,13 +126,12 @@ object Histogram {
     new Histogram[F, A] {
       val backend: Backend[F, A] =
         new Backend[F, A] {
-          val isEnabled: Boolean = false
-          val unit: F[Unit] = F.unit
-          def record(value: A, attributes: Attribute[_]*): F[Unit] = unit
+          val meta: Meta[F] = Meta.disabled
+          def record(value: A, attributes: Attribute[_]*): F[Unit] = meta.unit
           def recordDuration(
               timeUnit: TimeUnit,
               attributes: Attribute[_]*
-          ): Resource[F, Unit] = resourceUnit
+          ): Resource[F, Unit] = meta.resourceUnit
         }
     }
 
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/Meter.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Meter.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/Meter.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Meter.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/MeterBuilder.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/MeterBuilder.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/MeterBuilder.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/MeterBuilder.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/MeterProvider.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/MeterProvider.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/MeterProvider.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/MeterProvider.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/ObservableCounter.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableCounter.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/ObservableCounter.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableCounter.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/ObservableGauge.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableGauge.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/ObservableGauge.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableGauge.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/ObservableInstrumentBuilder.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableInstrumentBuilder.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/ObservableInstrumentBuilder.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableInstrumentBuilder.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/ObservableUpDownCounter.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableUpDownCounter.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/ObservableUpDownCounter.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/ObservableUpDownCounter.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/SyncInstrumentBuilder.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/SyncInstrumentBuilder.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/SyncInstrumentBuilder.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/SyncInstrumentBuilder.scala
diff --git a/core/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala
similarity index 83%
rename from core/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala
rename to core/metrics/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala
index 34aee773d..e957f7e9a 100644
--- a/core/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala
+++ b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/UpDownCounter.scala
@@ -18,6 +18,7 @@ package org.typelevel.otel4s
 package metrics
 
 import cats.Applicative
+import org.typelevel.otel4s.meta.InstrumentMeta
 
 /** A `Counter` instrument that records values of type `A`.
   *
@@ -37,7 +38,8 @@ trait UpDownCounter[F[_], A] extends UpDownCounterMacro[F, A]
 
 object UpDownCounter {
 
-  trait Backend[F[_], A] extends InstrumentBackend[F] {
+  trait Backend[F[_], A] {
+    def meta: InstrumentMeta[F]
 
     /** Records a value with a set of attributes.
       *
@@ -64,9 +66,7 @@ object UpDownCounter {
     def dec(attributes: Attribute[_]*): F[Unit]
   }
 
-  abstract class LongBackend[F[_]: Applicative] extends Backend[F, Long] {
-    final val unit: F[Unit] = Applicative[F].unit
-
+  trait LongBackend[F[_]] extends Backend[F, Long] {
     final def inc(attributes: Attribute[_]*): F[Unit] =
       add(1L, attributes: _*)
 
@@ -74,9 +74,7 @@ object UpDownCounter {
       add(-1L, attributes: _*)
   }
 
-  abstract class DoubleBackend[F[_]: Applicative] extends Backend[F, Double] {
-    val unit: F[Unit] = Applicative[F].unit
-
+  trait DoubleBackend[F[_]] extends Backend[F, Double] {
     final def inc(attributes: Attribute[_]*): F[Unit] =
       add(1.0, attributes: _*)
 
@@ -88,11 +86,10 @@ object UpDownCounter {
     new UpDownCounter[F, A] {
       val backend: UpDownCounter.Backend[F, A] =
         new UpDownCounter.Backend[F, A] {
-          val unit: F[Unit] = F.unit
-          val isEnabled: Boolean = false
-          def add(value: A, attributes: Attribute[_]*): F[Unit] = unit
-          def inc(attributes: Attribute[_]*): F[Unit] = unit
-          def dec(attributes: Attribute[_]*): F[Unit] = unit
+          val meta: InstrumentMeta[F] = InstrumentMeta.disabled
+          def add(value: A, attributes: Attribute[_]*): F[Unit] = meta.unit
+          def inc(attributes: Attribute[_]*): F[Unit] = meta.unit
+          def dec(attributes: Attribute[_]*): F[Unit] = meta.unit
         }
     }
 
diff --git a/core/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala
similarity index 96%
rename from core/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala
rename to core/metrics/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala
index 8d305b63d..2e49760a5 100644
--- a/core/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala
+++ b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/CounterSuite.scala
@@ -20,6 +20,7 @@ package metrics
 import cats.effect.IO
 import cats.effect.Ref
 import munit.CatsEffectSuite
+import org.typelevel.otel4s.meta.InstrumentMeta
 
 class CounterSuite extends CatsEffectSuite {
   import CounterSuite._
@@ -92,7 +93,7 @@ object CounterSuite {
 
     val backend: Counter.Backend[IO, Long] =
       new Counter.LongBackend[IO] {
-        val isEnabled: Boolean = true
+        val meta: InstrumentMeta[IO] = InstrumentMeta.enabled
 
         def add(value: Long, attributes: Attribute[_]*): IO[Unit] =
           ref.update(_.appended(Record(value, attributes)))
diff --git a/core/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala
similarity index 98%
rename from core/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala
rename to core/metrics/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala
index ebfd78a7d..c3c533679 100644
--- a/core/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala
+++ b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/HistogramSuite.scala
@@ -100,7 +100,7 @@ object HistogramSuite {
 
     val backend: Histogram.Backend[IO, Double] =
       new Histogram.DoubleBackend[IO] {
-        val isEnabled: Boolean = true
+        val meta: Histogram.Meta[IO] = Histogram.Meta.enabled
 
         def record(value: Double, attributes: Attribute[_]*): IO[Unit] =
           ref.update(_.appended(Record(value, attributes)))
diff --git a/core/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala
similarity index 96%
rename from core/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala
rename to core/metrics/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala
index 0b4ae6518..ebf3ee6fa 100644
--- a/core/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala
+++ b/core/metrics/src/test/scala/org/typelevel/otel4s/metrics/UpDownCounterSuite.scala
@@ -20,6 +20,7 @@ package metrics
 import cats.effect.IO
 import cats.effect.Ref
 import munit.CatsEffectSuite
+import org.typelevel.otel4s.meta.InstrumentMeta
 
 class UpDownCounterSuite extends CatsEffectSuite {
   import UpDownCounterSuite._
@@ -112,7 +113,7 @@ object UpDownCounterSuite {
 
     val backend: UpDownCounter.Backend[IO, Long] =
       new UpDownCounter.LongBackend[IO] {
-        val isEnabled: Boolean = true
+        val meta: InstrumentMeta[IO] = InstrumentMeta.enabled
 
         def add(value: Long, attributes: Attribute[_]*): IO[Unit] =
           ref.update(_.appended(Record(value, attributes)))
diff --git a/core/src/main/scala-2/org/typelevel/otel4s/metrics/MetricsMacro.scala b/core/src/main/scala-2/org/typelevel/otel4s/metrics/MetricsMacro.scala
deleted file mode 100644
index 7a0d1a192..000000000
--- a/core/src/main/scala-2/org/typelevel/otel4s/metrics/MetricsMacro.scala
+++ /dev/null
@@ -1,73 +0,0 @@
-/*
- * Copyright 2022 Typelevel
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.typelevel.otel4s
-package metrics
-
-import scala.concurrent.duration.TimeUnit
-import scala.reflect.macros.blackbox
-
-private[otel4s] object MetricsMacro {
-
-  def add[A](c: blackbox.Context)(
-      value: c.Expr[A],
-      attributes: c.Expr[Attribute[_]]*
-  ): c.universe.Tree = {
-    import c.universe._
-    val backend = q"${c.prefix}.backend"
-
-    q"if ($backend.isEnabled) $backend.add($value, ..$attributes) else $backend.unit"
-  }
-
-  def inc(c: blackbox.Context)(
-      attributes: c.Expr[Attribute[_]]*
-  ): c.universe.Tree = {
-    import c.universe._
-    val backend = q"${c.prefix}.backend"
-
-    q"if ($backend.isEnabled) $backend.inc(..$attributes) else $backend.unit"
-  }
-
-  def dec(c: blackbox.Context)(
-      attributes: c.Expr[Attribute[_]]*
-  ): c.universe.Tree = {
-    import c.universe._
-    val backend = q"${c.prefix}.backend"
-
-    q"if ($backend.isEnabled) $backend.dec(..$attributes) else $backend.unit"
-  }
-
-  def record[A](c: blackbox.Context)(
-      value: c.Expr[A],
-      attributes: c.Expr[Attribute[_]]*
-  ): c.universe.Tree = {
-    import c.universe._
-    val backend = q"${c.prefix}.backend"
-
-    q"if ($backend.isEnabled) $backend.record($value, ..$attributes) else $backend.unit"
-  }
-
-  def recordDuration(c: blackbox.Context)(
-      timeUnit: c.Expr[TimeUnit],
-      attributes: c.Expr[Attribute[_]]*
-  ): c.universe.Tree = {
-    import c.universe._
-    val backend = q"${c.prefix}.backend"
-
-    q"if ($backend.isEnabled) $backend.recordDuration($timeUnit, ..$attributes) else $backend.resourceUnit"
-  }
-
-}
diff --git a/core/src/main/scala-3/org/typelevel/otel4s/metrics/MetricsMacro.scala b/core/src/main/scala-3/org/typelevel/otel4s/metrics/MetricsMacro.scala
deleted file mode 100644
index fe8e4c059..000000000
--- a/core/src/main/scala-3/org/typelevel/otel4s/metrics/MetricsMacro.scala
+++ /dev/null
@@ -1,95 +0,0 @@
-/*
- * Copyright 2022 Typelevel
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.typelevel.otel4s
-package metrics
-
-import scala.concurrent.duration.TimeUnit
-import scala.quoted.*
-
-private[otel4s] object MetricsMacro {
-
-  object counter {
-
-    def add[F[_], A](
-        backend: Expr[Counter.Backend[F, A]],
-        value: Expr[A],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{
-        if ($backend.isEnabled) $backend.add($value, $attributes*)
-        else $backend.unit
-      }
-
-    def inc[F[_], A](
-        backend: Expr[Counter.Backend[F, A]],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{ if ($backend.isEnabled) $backend.inc($attributes*) else $backend.unit }
-
-  }
-
-  object upDownCounter {
-
-    def add[F[_], A](
-        backend: Expr[UpDownCounter.Backend[F, A]],
-        value: Expr[A],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{
-        if ($backend.isEnabled) $backend.add($value, $attributes*)
-        else $backend.unit
-      }
-
-    def inc[F[_], A](
-        backend: Expr[UpDownCounter.Backend[F, A]],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{ if ($backend.isEnabled) $backend.inc($attributes*) else $backend.unit }
-
-    def dec[F[_], A](
-        backend: Expr[UpDownCounter.Backend[F, A]],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{ if ($backend.isEnabled) $backend.dec($attributes*) else $backend.unit }
-
-  }
-
-  object histogram {
-
-    def record[F[_], A](
-        backend: Expr[Histogram.Backend[F, A]],
-        value: Expr[A],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{
-        if ($backend.isEnabled) $backend.record($value, $attributes*)
-        else $backend.unit
-      }
-
-    def recordDuration[F[_], A](
-        backend: Expr[Histogram.Backend[F, A]],
-        timeUnit: Expr[TimeUnit],
-        attributes: Expr[Seq[Attribute[_]]]
-    )(using Quotes, Type[F], Type[A]) =
-      '{
-        if ($backend.isEnabled) $backend.recordDuration($timeUnit, $attributes*)
-        else $backend.resourceUnit
-      }
-
-  }
-
-}
diff --git a/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala b/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
new file mode 100644
index 000000000..ce761a68c
--- /dev/null
+++ b/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.java
+
+import cats.effect.Sync
+import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
+import org.typelevel.otel4s.Otel4s
+import org.typelevel.otel4s.metrics.MeterProvider
+
+object OtelJava {
+
+  def forSync[F[_]](jOtel: JOpenTelemetry)(implicit F: Sync[F]): Otel4s[F] = {
+    new Otel4s[F] {
+      private val metrics = Metrics.forSync(jOtel)
+      def meterProvider: MeterProvider[F] = metrics.meterProvider
+    }
+  }
+
+}
diff --git a/java/common/src/main/scala/org/typelevel/otel4s/java/Conversions.scala b/java/common/src/main/scala/org/typelevel/otel4s/java/Conversions.scala
new file mode 100644
index 000000000..7a2d3fe1b
--- /dev/null
+++ b/java/common/src/main/scala/org/typelevel/otel4s/java/Conversions.scala
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+
+import io.opentelemetry.api.common.{AttributeKey => JAttributeKey}
+import io.opentelemetry.api.common.{AttributeType => JAttributeType}
+import io.opentelemetry.api.common.{Attributes => JAttributes}
+
+import scala.jdk.CollectionConverters._
+
+private[java] object Conversions {
+
+  def toJAttributes(attributes: Seq[Attribute[_]]): JAttributes = {
+    val builder = JAttributes.builder
+
+    def put(name: String, jType: JAttributeType, value: Any): Unit = {
+      val jKey = new JAttributeKey[Any] {
+        def getKey: String = name
+        def getType: JAttributeType = jType
+        override def toString: String = name
+      }
+      builder.put[Any](jKey, value)
+      ()
+    }
+
+    def putList(name: String, jType: JAttributeType, values: Any): Unit = {
+      val jKey = new JAttributeKey[Any] {
+        def getKey: String = name
+        def getType: JAttributeType = jType
+        override def toString: String = name
+      }
+      builder.put[Any](jKey, values.asInstanceOf[Seq[Any]].asJava)
+      ()
+    }
+
+    attributes.foreach { case Attribute(key, value) =>
+      key.`type` match {
+        case AttributeType.String =>
+          put(key.name, JAttributeType.STRING, value)
+        case AttributeType.Boolean =>
+          put(key.name, JAttributeType.BOOLEAN, value)
+        case AttributeType.Long =>
+          put(key.name, JAttributeType.LONG, value)
+        case AttributeType.Double =>
+          put(key.name, JAttributeType.DOUBLE, value)
+        case AttributeType.StringList =>
+          putList(key.name, JAttributeType.STRING_ARRAY, value)
+        case AttributeType.BooleanList =>
+          putList(key.name, JAttributeType.BOOLEAN_ARRAY, value)
+        case AttributeType.LongList =>
+          putList(key.name, JAttributeType.LONG_ARRAY, value)
+        case AttributeType.DoubleList =>
+          putList(key.name, JAttributeType.DOUBLE_ARRAY, value)
+      }
+    }
+    builder.build()
+  }
+
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
new file mode 100644
index 000000000..0590a3079
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.java
+
+import cats.effect.Sync
+import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
+import org.typelevel.otel4s.java.metrics.MeterProviderImpl
+import org.typelevel.otel4s.metrics.MeterProvider
+
+trait Metrics[F[_]] {
+  def meterProvider: MeterProvider[F]
+}
+
+object Metrics {
+
+  def forSync[F[_]: Sync](jOtel: JOpenTelemetry): Metrics[F] =
+    new Metrics[F] {
+      val meterProvider: MeterProvider[F] = new MeterProviderImpl[F](jOtel)
+    }
+
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
new file mode 100644
index 000000000..471d04f54
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{Meter => JMeter}
+import org.typelevel.otel4s.metrics._
+
+private[java] case class CounterBuilderImpl[F[_]](
+    jMeter: JMeter,
+    name: String,
+    unit: Option[String] = None,
+    description: Option[String] = None
+)(implicit F: Sync[F])
+    extends SyncInstrumentBuilder[F, Counter[F, Long]] {
+  type Self = CounterBuilderImpl[F]
+
+  def withUnit(unit: String): Self = copy(unit = Option(unit))
+
+  def withDescription(description: String): Self =
+    copy(description = Option(description))
+
+  def create: F[Counter[F, Long]] = F.delay {
+    val b = jMeter.counterBuilder(name)
+    unit.foreach(b.setUnit)
+    description.foreach(b.setDescription)
+    new CounterImpl(b.build)
+  }
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
new file mode 100644
index 000000000..ed4c619a1
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{LongCounter => JLongCounter}
+import org.typelevel.otel4s.meta.InstrumentMeta
+import org.typelevel.otel4s.metrics._
+
+private[java] class CounterImpl[F[_]](
+    longCounter: JLongCounter
+)(implicit F: Sync[F])
+    extends Counter[F, Long] {
+
+  val backend: Counter.Backend[F, Long] =
+    new Counter.LongBackend[F] {
+      val meta: InstrumentMeta[F] = InstrumentMeta.enabled
+
+      def add(value: Long, attributes: Attribute[_]*): F[Unit] =
+        F.delay(longCounter.add(value, Conversions.toJAttributes(attributes)))
+    }
+
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
new file mode 100644
index 000000000..f6c2a0213
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{Meter => JMeter}
+import org.typelevel.otel4s.metrics._
+
+private[java] case class HistogramBuilderImpl[F[_]](
+    jMeter: JMeter,
+    name: String,
+    unit: Option[String] = None,
+    description: Option[String] = None
+)(implicit F: Sync[F])
+    extends SyncInstrumentBuilder[F, Histogram[F, Double]] {
+  type Self = HistogramBuilderImpl[F]
+
+  def withUnit(unit: String): Self = copy(unit = Option(unit))
+
+  def withDescription(description: String): Self =
+    copy(description = Option(description))
+
+  def create: F[Histogram[F, Double]] = F.delay {
+    val b = jMeter.histogramBuilder(name)
+    unit.foreach(b.setUnit)
+    description.foreach(b.setDescription)
+    new HistogramImpl(b.build)
+  }
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
new file mode 100644
index 000000000..94844ddaf
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{DoubleHistogram => JDoubleHistogram}
+import org.typelevel.otel4s.metrics._
+
+private[java] class HistogramImpl[F[_]](
+    histogram: JDoubleHistogram
+)(implicit F: Sync[F])
+    extends Histogram[F, Double] {
+
+  val backend: Histogram.Backend[F, Double] =
+    new Histogram.DoubleBackend[F] {
+      val meta: Histogram.Meta[F] = Histogram.Meta.enabled
+
+      def record(value: Double, attributes: Attribute[_]*): F[Unit] =
+        F.delay(
+          histogram.record(value, Conversions.toJAttributes(attributes))
+        )
+    }
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
new file mode 100644
index 000000000..400734d54
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
+import org.typelevel.otel4s.metrics._
+
+private[java] case class MeterBuilderImpl[F[_]](
+    jOtel: JOpenTelemetry,
+    name: String,
+    version: Option[String] = None,
+    schemaUrl: Option[String] = None
+)(implicit F: Sync[F])
+    extends MeterBuilder[F] {
+  def withVersion(version: String): MeterBuilder[F] =
+    copy(version = Option(version))
+
+  def withSchemaUrl(schemaUrl: String): MeterBuilder[F] =
+    copy(schemaUrl = Option(schemaUrl))
+
+  def get: F[Meter[F]] = F.delay {
+    val b = jOtel.meterBuilder(name)
+    version.foreach(b.setInstrumentationVersion)
+    schemaUrl.foreach(b.setSchemaUrl)
+    new MeterImpl(b.build())
+  }
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
new file mode 100644
index 000000000..0d34f181e
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{Meter => JMeter}
+import org.typelevel.otel4s.metrics._
+
+private[java] class MeterImpl[F[_]: Sync](jMeter: JMeter) extends Meter[F] {
+  def counter(name: String): SyncInstrumentBuilder[F, Counter[F, Long]] =
+    new CounterBuilderImpl(jMeter, name)
+
+  def histogram(
+      name: String
+  ): SyncInstrumentBuilder[F, Histogram[F, Double]] =
+    new HistogramBuilderImpl(jMeter, name)
+
+  def upDownCounter(
+      name: String
+  ): SyncInstrumentBuilder[F, UpDownCounter[F, Long]] =
+    new UpDownCounterBuilderImpl(jMeter, name)
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
new file mode 100644
index 000000000..c934ecc7f
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
+import org.typelevel.otel4s.metrics.MeterBuilder
+import org.typelevel.otel4s.metrics.MeterProvider
+
+private[java] class MeterProviderImpl[F[_]: Sync](
+    jOtel: JOpenTelemetry
+) extends MeterProvider[F] {
+
+  def meter(name: String): MeterBuilder[F] = new MeterBuilderImpl(jOtel, name)
+
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
new file mode 100644
index 000000000..2cb1a0f50
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{Meter => JMeter}
+import org.typelevel.otel4s.metrics._
+
+private[java] case class UpDownCounterBuilderImpl[F[_]](
+    jMeter: JMeter,
+    name: String,
+    unit: Option[String] = None,
+    description: Option[String] = None
+)(implicit F: Sync[F])
+    extends SyncInstrumentBuilder[F, UpDownCounter[F, Long]] {
+  type Self = UpDownCounterBuilderImpl[F]
+
+  def withUnit(unit: String): UpDownCounterBuilderImpl[F] =
+    copy(unit = Option(unit))
+
+  def withDescription(description: String): UpDownCounterBuilderImpl[F] =
+    copy(description = Option(description))
+
+  def create: F[UpDownCounter[F, Long]] = F.delay {
+    val b = jMeter.upDownCounterBuilder(name)
+    unit.foreach(b.setUnit)
+    description.foreach(b.setDescription)
+    new UpDownCounterImpl(b.build)
+  }
+}
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
new file mode 100644
index 000000000..f9b763860
--- /dev/null
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s
+package java
+package metrics
+
+import cats.effect.Sync
+import io.opentelemetry.api.metrics.{LongUpDownCounter => JLongUpDownCounter}
+import org.typelevel.otel4s.meta.InstrumentMeta
+import org.typelevel.otel4s.metrics._
+
+private[java] class UpDownCounterImpl[F[_]](
+    counter: JLongUpDownCounter
+)(implicit F: Sync[F])
+    extends UpDownCounter[F, Long] {
+
+  val backend: UpDownCounter.Backend[F, Long] =
+    new UpDownCounter.LongBackend[F] {
+      val meta: InstrumentMeta[F] = InstrumentMeta.enabled
+
+      def add(value: Long, attributes: Attribute[_]*): F[Unit] =
+        F.delay(counter.add(value, Conversions.toJAttributes(attributes)))
+
+    }
+}
diff --git a/java/src/test/scala/org/typelevel/otel4s/java/JavaOtelSuite.scala b/java/metrics/src/test/scala/org/typelevel/otel4s/java/metrics/CounterSuite.scala
similarity index 89%
rename from java/src/test/scala/org/typelevel/otel4s/java/JavaOtelSuite.scala
rename to java/metrics/src/test/scala/org/typelevel/otel4s/java/metrics/CounterSuite.scala
index f2ee27f2b..5f589298b 100644
--- a/java/src/test/scala/org/typelevel/otel4s/java/JavaOtelSuite.scala
+++ b/java/metrics/src/test/scala/org/typelevel/otel4s/java/metrics/CounterSuite.scala
@@ -16,21 +16,24 @@
 
 package org.typelevel.otel4s
 package java
+package metrics
 
 import cats.effect.IO
 import io.opentelemetry.sdk.metrics._
 import munit.CatsEffectSuite
 import org.typelevel.otel4s.testkit._
+import org.typelevel.otel4s.testkit.metrics.MetricsSdk
 
 import scala.jdk.CollectionConverters._
 
-class JavaOtelSuite extends CatsEffectSuite {
+class CounterSuite extends CatsEffectSuite {
 
   test("Counter record a proper data") {
     for {
       sdk <- IO.delay(makeSdk)
-      otel4s <- IO.delay(OtelJava.forSync[IO](sdk.sdk))
-      meter <- otel4s.meterProvider
+      meter <- Metrics
+        .forSync[IO](sdk.sdk)
+        .meterProvider
         .meter("java.otel.suite")
         .withVersion("1.0")
         .withSchemaUrl("https://localhost:8080")
@@ -67,7 +70,7 @@ class JavaOtelSuite extends CatsEffectSuite {
       assertEquals(metrics.map(_.unit), List(Some("unit")))
       assertEquals(
         metrics.map(_.resource),
-        List(new MetricResource(None, resourceAttributes))
+        List(new InstrumentationResource(None, resourceAttributes))
       )
       assertEquals(metrics.map(_.scope), List(scope))
       assertEquals[List[Any], List[Any]](
@@ -77,7 +80,7 @@ class JavaOtelSuite extends CatsEffectSuite {
     }
   }
 
-  private def makeSdk: Sdk[IO] = {
+  private def makeSdk: MetricsSdk[IO] = {
     def customize(builder: SdkMeterProviderBuilder): SdkMeterProviderBuilder =
       builder.registerView(
         InstrumentSelector.builder().setType(InstrumentType.HISTOGRAM).build(),
@@ -91,7 +94,7 @@ class JavaOtelSuite extends CatsEffectSuite {
           .build()
       )
 
-    Sdk.create[IO](customize)
+    MetricsSdk.create[IO](customize)
   }
 
   private val HistogramBuckets: List[Double] =
diff --git a/java/src/main/scala/org/typelevel/otel4s/java/impl.scala b/java/src/main/scala/org/typelevel/otel4s/java/impl.scala
deleted file mode 100644
index b09e3d2e7..000000000
--- a/java/src/main/scala/org/typelevel/otel4s/java/impl.scala
+++ /dev/null
@@ -1,226 +0,0 @@
-/*
- * Copyright 2022 Typelevel
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.typelevel.otel4s
-package java
-
-import cats.effect.Sync
-import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
-import io.opentelemetry.api.common.{AttributeKey => JAttributeKey}
-import io.opentelemetry.api.common.{AttributeType => JAttributeType}
-import io.opentelemetry.api.common.{Attributes => JAttributes}
-import io.opentelemetry.api.metrics.{DoubleHistogram => JDoubleHistogram}
-import io.opentelemetry.api.metrics.{LongCounter => JLongCounter}
-import io.opentelemetry.api.metrics.{LongUpDownCounter => JLongUpDownCounter}
-import io.opentelemetry.api.metrics.{Meter => JMeter}
-import org.typelevel.otel4s.metrics._
-
-import scala.jdk.CollectionConverters._
-
-object OtelJava {
-  def forSync[F[_]](jOtel: JOpenTelemetry)(implicit F: Sync[F]): Otel4s[F] =
-    new Otel4s[F] {
-      def meterProvider: MeterProvider[F] = new MeterProviderImpl[F](jOtel)
-    }
-
-  private class MeterProviderImpl[F[_]: Sync](jOtel: JOpenTelemetry)
-      extends MeterProvider[F] {
-    def meter(name: String): MeterBuilder[F] = new MeterBuilderImpl(jOtel, name)
-  }
-
-  private case class MeterBuilderImpl[F[_]](
-      jOtel: JOpenTelemetry,
-      name: String,
-      version: Option[String] = None,
-      schemaUrl: Option[String] = None
-  )(implicit F: Sync[F])
-      extends MeterBuilder[F] {
-    def withVersion(version: String): MeterBuilder[F] =
-      copy(version = Option(version))
-    def withSchemaUrl(schemaUrl: String): MeterBuilder[F] =
-      copy(schemaUrl = Option(schemaUrl))
-
-    def get: F[Meter[F]] = F.delay {
-      val b = jOtel.meterBuilder(name)
-      version.foreach(b.setInstrumentationVersion)
-      schemaUrl.foreach(b.setSchemaUrl)
-      new MeterImpl(b.build())
-    }
-  }
-
-  private class MeterImpl[F[_]: Sync](jMeter: JMeter) extends Meter[F] {
-    def counter(name: String): SyncInstrumentBuilder[F, Counter[F, Long]] =
-      new CounterBuilderImpl(jMeter, name)
-
-    def histogram(
-        name: String
-    ): SyncInstrumentBuilder[F, Histogram[F, Double]] =
-      new HistogramBuilderImpl(jMeter, name)
-
-    def upDownCounter(
-        name: String
-    ): SyncInstrumentBuilder[F, UpDownCounter[F, Long]] =
-      new UpDownCounterBuilderImpl(jMeter, name)
-  }
-
-  private case class CounterBuilderImpl[F[_]](
-      jMeter: JMeter,
-      name: String,
-      unit: Option[String] = None,
-      description: Option[String] = None
-  )(implicit F: Sync[F])
-      extends SyncInstrumentBuilder[F, Counter[F, Long]] {
-    type Self = CounterBuilderImpl[F]
-
-    def withUnit(unit: String): Self = copy(unit = Option(unit))
-    def withDescription(description: String): Self =
-      copy(description = Option(description))
-
-    def create: F[Counter[F, Long]] = F.delay {
-      val b = jMeter.counterBuilder(name)
-      unit.foreach(b.setUnit)
-      description.foreach(b.setDescription)
-      new CounterImpl(b.build)
-    }
-  }
-
-  private class CounterImpl[F[_]](longCounter: JLongCounter)(implicit
-      F: Sync[F]
-  ) extends Counter[F, Long] {
-
-    val backend: Counter.Backend[F, Long] =
-      new Counter.LongBackend[F] {
-        val isEnabled: Boolean = true
-
-        def add(value: Long, attributes: Attribute[_]*): F[Unit] =
-          F.delay(longCounter.add(value, toJAttributes(attributes)))
-      }
-
-  }
-
-  private case class HistogramBuilderImpl[F[_]](
-      jMeter: JMeter,
-      name: String,
-      unit: Option[String] = None,
-      description: Option[String] = None
-  )(implicit F: Sync[F])
-      extends SyncInstrumentBuilder[F, Histogram[F, Double]] {
-    type Self = HistogramBuilderImpl[F]
-
-    def withUnit(unit: String): Self = copy(unit = Option(unit))
-    def withDescription(description: String): Self =
-      copy(description = Option(description))
-
-    def create: F[Histogram[F, Double]] = F.delay {
-      val b = jMeter.histogramBuilder(name)
-      unit.foreach(b.setUnit)
-      description.foreach(b.setDescription)
-      new HistogramImpl(b.build)
-    }
-  }
-
-  private class HistogramImpl[F[_]](histogram: JDoubleHistogram)(implicit
-      F: Sync[F]
-  ) extends Histogram[F, Double] {
-
-    val backend: Histogram.Backend[F, Double] =
-      new Histogram.DoubleBackend[F] {
-        val isEnabled: Boolean = true
-        def record(value: Double, attributes: Attribute[_]*): F[Unit] =
-          F.delay(histogram.record(value, toJAttributes(attributes)))
-      }
-  }
-
-  private case class UpDownCounterBuilderImpl[F[_]](
-      jMeter: JMeter,
-      name: String,
-      unit: Option[String] = None,
-      description: Option[String] = None
-  )(implicit F: Sync[F])
-      extends SyncInstrumentBuilder[F, UpDownCounter[F, Long]] {
-    type Self = UpDownCounterBuilderImpl[F]
-
-    def withUnit(unit: String) =
-      copy(unit = Option(unit))
-
-    def withDescription(description: String) =
-      copy(description = Option(description))
-
-    def create: F[UpDownCounter[F, Long]] = F.delay {
-      val b = jMeter.upDownCounterBuilder(name)
-      unit.foreach(b.setUnit)
-      description.foreach(b.setDescription)
-      new UpDownCounterImpl(b.build)
-    }
-  }
-
-  private class UpDownCounterImpl[F[_]](counter: JLongUpDownCounter)(implicit
-      F: Sync[F]
-  ) extends UpDownCounter[F, Long] {
-
-    val backend: UpDownCounter.Backend[F, Long] =
-      new UpDownCounter.LongBackend[F] {
-        val isEnabled: Boolean = true
-
-        def add(value: Long, attributes: Attribute[_]*): F[Unit] =
-          F.delay(counter.add(value, toJAttributes(attributes)))
-
-      }
-  }
-
-  private def toJAttributes(attributes: Seq[Attribute[_]]): JAttributes = {
-    val builder = JAttributes.builder
-    def put(name: String, jType: JAttributeType, value: Any): Unit = {
-      val jKey = new JAttributeKey[Any] {
-        def getKey = name
-        def getType = jType
-        override def toString = name
-      }
-      builder.put[Any](jKey, value)
-      ()
-    }
-    def putList(name: String, jType: JAttributeType, values: Any): Unit = {
-      val jKey = new JAttributeKey[Any] {
-        def getKey = name
-        def getType = jType
-        override def toString = name
-      }
-      builder.put[Any](jKey, values.asInstanceOf[Seq[Any]].asJava)
-      ()
-    }
-    attributes.foreach { case Attribute(key, value) =>
-      key.`type` match {
-        case AttributeType.String =>
-          put(key.name, JAttributeType.STRING, value)
-        case AttributeType.Boolean =>
-          put(key.name, JAttributeType.BOOLEAN, value)
-        case AttributeType.Long =>
-          put(key.name, JAttributeType.LONG, value)
-        case AttributeType.Double =>
-          put(key.name, JAttributeType.DOUBLE, value)
-        case AttributeType.StringList =>
-          putList(key.name, JAttributeType.STRING_ARRAY, value)
-        case AttributeType.BooleanList =>
-          putList(key.name, JAttributeType.BOOLEAN_ARRAY, value)
-        case AttributeType.LongList =>
-          putList(key.name, JAttributeType.LONG_ARRAY, value)
-        case AttributeType.DoubleList =>
-          putList(key.name, JAttributeType.DOUBLE_ARRAY, value)
-      }
-    }
-    builder.build()
-  }
-}
diff --git a/java/src/test/scala/com/example/PoC.scala b/java/src/test/scala/com/example/PoC.scala
deleted file mode 100644
index abe3f6fe2..000000000
--- a/java/src/test/scala/com/example/PoC.scala
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * Copyright 2022 Typelevel
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.example
-
-import cats.effect.IO
-import cats.effect.IOApp
-import cats.syntax.foldable._
-import io.opentelemetry.sdk.OpenTelemetrySdk
-import io.opentelemetry.sdk.metrics.SdkMeterProvider
-import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader
-import org.typelevel.otel4s.Attribute
-import org.typelevel.otel4s.AttributeKey
-import org.typelevel.otel4s.java.OtelJava
-
-import scala.jdk.CollectionConverters._
-
-object Poc extends IOApp.Simple {
-
-  def run: IO[Unit] = for {
-    jMetricReader <- IO(InMemoryMetricReader.create())
-    otel4j <- IO {
-      val meterProvider = SdkMeterProvider
-        .builder()
-        .registerMetricReader(jMetricReader)
-        .build()
-
-      val sdk = OpenTelemetrySdk
-        .builder()
-        .setMeterProvider(meterProvider)
-        .build()
-
-      sdk
-    }
-    otel4s = OtelJava.forSync[IO](otel4j)
-    meter <- otel4s.meterProvider.get("poc")
-    counter <- meter.counter("test").create
-    _ <- counter.add(1)
-    dog = AttributeKey.string("dog")
-    fish = AttributeKey.stringList("fish")
-    numbers = AttributeKey.longList("numbers")
-    _ <- counter.add(
-      2,
-      Attribute(dog, "barking"),
-      Attribute(fish, List("one", "two", "red", "blue")),
-      Attribute(numbers, List(1L, 2L, 3L, 4L))
-    )
-    _ <- jMetricReader.collectAllMetrics().asScala.toList.traverse_(IO.println)
-  } yield ()
-}
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/Implicits.scala b/testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/Implicits.scala
similarity index 100%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/Implicits.scala
rename to testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/Implicits.scala
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricResource.scala b/testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationResource.scala
similarity index 67%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricResource.scala
rename to testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationResource.scala
index 1505292c0..3418e4e85 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricResource.scala
+++ b/testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationResource.scala
@@ -21,34 +21,36 @@ import cats.Hash
 import cats.Show
 import cats.syntax.show._
 
-final class MetricResource(
+final class InstrumentationResource(
     val schemaUrl: Option[String],
     val attributes: List[Attribute[_]]
 ) {
 
   override def hashCode(): Int =
-    Hash[MetricResource].hash(this)
+    Hash[InstrumentationResource].hash(this)
 
   override def toString: String =
-    Show[MetricResource].show(this)
+    Show[InstrumentationResource].show(this)
 
   override def equals(obj: Any): Boolean =
     obj match {
-      case other: MetricResource =>
-        Hash[MetricResource].eqv(this, other)
+      case other: InstrumentationResource =>
+        Hash[InstrumentationResource].eqv(this, other)
       case _ =>
         false
     }
 
 }
 
-object MetricResource {
+object InstrumentationResource {
   import Implicits._
 
-  implicit val metricResourceHash: Hash[MetricResource] =
+  implicit val metricResourceHash: Hash[InstrumentationResource] =
     Hash.by(p => (p.schemaUrl, p.attributes))
 
-  implicit val metricResourceShow: Show[MetricResource] =
-    Show.show(p => show"MetricResource(${p.schemaUrl}, ${p.attributes})")
+  implicit val metricResourceShow: Show[InstrumentationResource] =
+    Show.show(p =>
+      show"InstrumentationResource(${p.schemaUrl}, ${p.attributes})"
+    )
 
 }
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationScope.scala b/testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationScope.scala
similarity index 100%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationScope.scala
rename to testkit/common/shared/src/main/scala/org/typelevel/otel4s/testkit/InstrumentationScope.scala
diff --git a/testkit/jvm/src/main/scala/org/typelevel/otel4s/testkit/Sdk.scala b/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
similarity index 97%
rename from testkit/jvm/src/main/scala/org/typelevel/otel4s/testkit/Sdk.scala
rename to testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
index acf821b70..ad77febbb 100644
--- a/testkit/jvm/src/main/scala/org/typelevel/otel4s/testkit/Sdk.scala
+++ b/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
@@ -16,6 +16,7 @@
 
 package org.typelevel.otel4s
 package testkit
+package metrics
 
 import cats.effect.Sync
 import io.opentelemetry.api.common.{AttributeType => JAttributeType}
@@ -39,16 +40,16 @@ import java.{lang => jl}
 import java.{util => ju}
 import scala.jdk.CollectionConverters._
 
-trait Sdk[F[_]] {
+trait MetricsSdk[F[_]] {
   def sdk: OpenTelemetrySdk
   def metrics: F[List[Metric]]
 }
 
-object Sdk {
+object MetricsSdk {
 
   def create[F[_]: Sync](
       customize: SdkMeterProviderBuilder => SdkMeterProviderBuilder = identity
-  ): Sdk[F] = {
+  ): MetricsSdk[F] = {
     val metricReader = InMemoryMetricReader.create()
 
     val meterProviderBuilder = SdkMeterProvider
@@ -62,7 +63,7 @@ object Sdk {
       .setMeterProvider(meterProvider)
       .build()
 
-    new Sdk[F] {
+    new MetricsSdk[F] {
       val sdk: OpenTelemetrySdk = openTelemetrySdk
 
       def metrics: F[List[Metric]] =
@@ -173,7 +174,7 @@ object Sdk {
         version = Option(scope.getVersion),
         schemaUrl = Option(scope.getSchemaUrl)
       ),
-      resource = new MetricResource(
+      resource = new InstrumentationResource(
         schemaUrl = Option(resource.getSchemaUrl),
         attributes = collectAttributes(resource.getAttributes)
       ),
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/HistogramPointData.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/HistogramPointData.scala
similarity index 97%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/HistogramPointData.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/HistogramPointData.scala
index ffd3fcdbb..f2bcc384a 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/HistogramPointData.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/HistogramPointData.scala
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.testkit
+package org.typelevel.otel4s.testkit.metrics
 
 import cats.Hash
 import cats.Show
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/Metric.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/Metric.scala
similarity index 96%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/Metric.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/Metric.scala
index 80d02f3fa..b6f7d0a34 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/Metric.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/Metric.scala
@@ -15,6 +15,7 @@
  */
 
 package org.typelevel.otel4s.testkit
+package metrics
 
 import cats.Hash
 import cats.Show
@@ -25,7 +26,7 @@ final class Metric(
     val description: Option[String],
     val unit: Option[String],
     val scope: InstrumentationScope,
-    val resource: MetricResource,
+    val resource: InstrumentationResource,
     val data: MetricData
 ) {
 
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricData.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricData.scala
similarity index 98%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricData.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricData.scala
index ccd7d9230..f4dc21df4 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/MetricData.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricData.scala
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.testkit
+package org.typelevel.otel4s.testkit.metrics
 
 import cats.Hash
 import cats.Show
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/PointData.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/PointData.scala
similarity index 98%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/PointData.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/PointData.scala
index 80392cda9..3649f1f0c 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/PointData.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/PointData.scala
@@ -16,6 +16,7 @@
 
 package org.typelevel.otel4s
 package testkit
+package metrics
 
 import cats.Hash
 import cats.Show
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/QuantileData.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/QuantileData.scala
similarity index 96%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/QuantileData.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/QuantileData.scala
index 73b35ff5f..cd73ddeec 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/QuantileData.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/QuantileData.scala
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.testkit
+package org.typelevel.otel4s.testkit.metrics
 
 import cats.Hash
 import cats.Show
diff --git a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/SummaryPointData.scala b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/SummaryPointData.scala
similarity index 96%
rename from testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/SummaryPointData.scala
rename to testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/SummaryPointData.scala
index 34cbba560..055fb951a 100644
--- a/testkit/shared/src/main/scala/org/typelevel/otel4s/testkit/SummaryPointData.scala
+++ b/testkit/metrics/shared/src/main/scala/org/typelevel/otel4s/testkit/metrics/SummaryPointData.scala
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.testkit
+package org.typelevel.otel4s.testkit.metrics
 
 import cats.Hash
 import cats.Show

From f24f9dae449aa64e0700d0a587bb52f9d2ceb54a Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 3 Aug 2022 14:52:49 +0300
Subject: [PATCH 2/3] Do not use `crossProject` with `java` modules

---
 .github/workflows/ci.yml |  4 ++--
 build.sbt                | 15 ++++++---------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2a26a224f..c52d3f665 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -94,11 +94,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p testkit/metrics/jvm/target testkit/common/jvm/target target java/common/.jvm/target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target java/metrics/.jvm/target core/all/.js/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target java/all/.jvm/target testkit/all/jvm/target project/target
+        run: mkdir -p testkit/metrics/jvm/target java/metrics/target testkit/common/jvm/target target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target core/all/.js/target java/all/target java/common/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target testkit/all/jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar testkit/metrics/jvm/target testkit/common/jvm/target target java/common/.jvm/target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target java/metrics/.jvm/target core/all/.js/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target java/all/.jvm/target testkit/all/jvm/target project/target
+        run: tar cf targets.tar testkit/metrics/jvm/target java/metrics/target testkit/common/jvm/target target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target core/all/.js/target java/all/target java/common/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target testkit/all/jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
diff --git a/build.sbt b/build.sbt
index 1f04f66c1..ce94f7877 100644
--- a/build.sbt
+++ b/build.sbt
@@ -113,10 +113,9 @@ lazy val testkit = crossProject(JVMPlatform)
     name := "otel4s-testkit"
   )
 
-lazy val `java-common` = crossProject(JVMPlatform)
-  .crossType(CrossType.Pure)
+lazy val `java-common` = project
   .in(file("java/common"))
-  .dependsOn(`core-common`, `testkit-common`)
+  .dependsOn(`core-common`.jvm, `testkit-common`.jvm)
   .settings(
     name := "otel4s-java-common",
     libraryDependencies ++= Seq(
@@ -124,10 +123,9 @@ lazy val `java-common` = crossProject(JVMPlatform)
     )
   )
 
-lazy val `java-metrics` = crossProject(JVMPlatform)
-  .crossType(CrossType.Pure)
+lazy val `java-metrics` = project
   .in(file("java/metrics"))
-  .dependsOn(`java-common`, `core-metrics`, `testkit-metrics`)
+  .dependsOn(`java-common`, `core-metrics`.jvm, `testkit-metrics`.jvm)
   .settings(
     name := "otel4s-java-metrics",
     libraryDependencies ++= Seq(
@@ -139,10 +137,9 @@ lazy val `java-metrics` = crossProject(JVMPlatform)
     )
   )
 
-lazy val java = crossProject(JVMPlatform)
-  .crossType(CrossType.Pure)
+lazy val java = project
   .in(file("java/all"))
-  .dependsOn(core, `java-metrics`)
+  .dependsOn(core.jvm, `java-metrics`)
   .settings(
     name := "otel4s-java"
   )

From 0d3235c0ae8195239d4812effed2f9ffa9221975 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 3 Aug 2022 18:34:35 +0300
Subject: [PATCH 3/3] Use `cats-effect-kernel` in `core-metrics` module

---
 build.sbt                                                     | 2 +-
 .../scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala | 2 +-
 .../scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala | 2 +-
 .../main/scala/org/typelevel/otel4s/metrics/Histogram.scala   | 4 ++--
 .../src/main/scala/org/typelevel/otel4s/java/OtelJava.scala   | 2 +-
 .../src/main/scala/org/typelevel/otel4s/java/Metrics.scala    | 2 +-
 .../typelevel/otel4s/java/metrics/CounterBuilderImpl.scala    | 2 +-
 .../scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala | 2 +-
 .../typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala  | 2 +-
 .../org/typelevel/otel4s/java/metrics/HistogramImpl.scala     | 2 +-
 .../org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala  | 2 +-
 .../scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala   | 2 +-
 .../org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala | 2 +-
 .../otel4s/java/metrics/UpDownCounterBuilderImpl.scala        | 2 +-
 .../org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala | 2 +-
 .../org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala     | 2 +-
 16 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/build.sbt b/build.sbt
index ce94f7877..07925aafc 100644
--- a/build.sbt
+++ b/build.sbt
@@ -67,7 +67,7 @@ lazy val `core-metrics` = crossProject(JVMPlatform, JSPlatform)
   .settings(
     name := "otel4s-core-metrics",
     libraryDependencies ++= Seq(
-      "org.typelevel" %%% "cats-effect" % CatsEffectVersion,
+      "org.typelevel" %%% "cats-effect-kernel" % CatsEffectVersion,
       "org.scalameta" %%% "munit" % MUnitVersion % Test,
       "org.typelevel" %%% "munit-cats-effect-3" % MUnitCatsEffectVersion % Test,
       "org.typelevel" %%% "cats-effect-testkit" % CatsEffectVersion % Test
diff --git a/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
index e40346866..168fc3a01 100644
--- a/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
+++ b/core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala
@@ -17,7 +17,7 @@
 package org.typelevel.otel4s
 package metrics
 
-import cats.effect.Resource
+import cats.effect.kernel.Resource
 
 import scala.concurrent.duration.TimeUnit
 
diff --git a/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
index ad964d627..7132551da 100644
--- a/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
+++ b/core/metrics/src/main/scala-3/org/typelevel/otel4s/metrics/HistogramMacro.scala
@@ -17,7 +17,7 @@
 package org.typelevel.otel4s
 package metrics
 
-import cats.effect.Resource
+import cats.effect.kernel.Resource
 
 import scala.concurrent.duration._
 import scala.quoted.*
diff --git a/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
index ec7e97bfa..71fd4d2b2 100644
--- a/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
+++ b/core/metrics/src/main/scala/org/typelevel/otel4s/metrics/Histogram.scala
@@ -19,8 +19,8 @@ package metrics
 
 import cats.Applicative
 import cats.Monad
-import cats.effect.Clock
-import cats.effect.Resource
+import cats.effect.kernel.Clock
+import cats.effect.kernel.Resource
 import cats.syntax.flatMap._
 import cats.syntax.functor._
 import org.typelevel.otel4s.meta.InstrumentMeta
diff --git a/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala b/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
index ce761a68c..c57e4a7a3 100644
--- a/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
+++ b/java/all/src/main/scala/org/typelevel/otel4s/java/OtelJava.scala
@@ -16,7 +16,7 @@
 
 package org.typelevel.otel4s.java
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
 import org.typelevel.otel4s.Otel4s
 import org.typelevel.otel4s.metrics.MeterProvider
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
index 0590a3079..dff6c032b 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/Metrics.scala
@@ -16,7 +16,7 @@
 
 package org.typelevel.otel4s.java
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
 import org.typelevel.otel4s.java.metrics.MeterProviderImpl
 import org.typelevel.otel4s.metrics.MeterProvider
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
index 471d04f54..08ae3a63f 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterBuilderImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{Meter => JMeter}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
index ed4c619a1..1744c91de 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/CounterImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{LongCounter => JLongCounter}
 import org.typelevel.otel4s.meta.InstrumentMeta
 import org.typelevel.otel4s.metrics._
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
index f6c2a0213..7392d3b7a 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramBuilderImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{Meter => JMeter}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
index 94844ddaf..29b9332f6 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/HistogramImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{DoubleHistogram => JDoubleHistogram}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
index 400734d54..2a43f2f4e 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterBuilderImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
index 0d34f181e..bfcc97838 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{Meter => JMeter}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
index c934ecc7f..158d83a5b 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/MeterProviderImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.{OpenTelemetry => JOpenTelemetry}
 import org.typelevel.otel4s.metrics.MeterBuilder
 import org.typelevel.otel4s.metrics.MeterProvider
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
index 2cb1a0f50..a9a806031 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterBuilderImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{Meter => JMeter}
 import org.typelevel.otel4s.metrics._
 
diff --git a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
index f9b763860..9894c3c66 100644
--- a/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
+++ b/java/metrics/src/main/scala/org/typelevel/otel4s/java/metrics/UpDownCounterImpl.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package java
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.metrics.{LongUpDownCounter => JLongUpDownCounter}
 import org.typelevel.otel4s.meta.InstrumentMeta
 import org.typelevel.otel4s.metrics._
diff --git a/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala b/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
index ad77febbb..632ab8ed8 100644
--- a/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
+++ b/testkit/metrics/jvm/src/main/scala/org/typelevel/otel4s/testkit/metrics/MetricsSdk.scala
@@ -18,7 +18,7 @@ package org.typelevel.otel4s
 package testkit
 package metrics
 
-import cats.effect.Sync
+import cats.effect.kernel.Sync
 import io.opentelemetry.api.common.{AttributeType => JAttributeType}
 import io.opentelemetry.api.common.{Attributes => JAttributes}
 import io.opentelemetry.sdk.OpenTelemetrySdk