diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/AsynchronousInstrument.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/AsynchronousInstrument.java
index 1a7fcb938c..21b536936d 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/AsynchronousInstrument.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/AsynchronousInstrument.java
@@ -6,6 +6,7 @@
 package io.opentelemetry.api.metrics;
 
 import io.opentelemetry.api.common.Labels;
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -19,22 +20,17 @@ import javax.annotation.concurrent.ThreadSafe;
  */
 @ThreadSafe
 public interface AsynchronousInstrument extends Instrument {
-  /** A {@code Callback} for a {@code AsynchronousInstrument}. */
-  interface Callback<R extends Result> {
-    void update(R result);
-  }
-
   /** Builder class for {@link AsynchronousInstrument}. */
   interface Builder<R extends Result> extends Instrument.Builder {
     /**
-     * Sets a callback that gets executed every collection interval.
+     * Sets a consumer that gets executed every collection interval.
      *
      * <p>Evaluation is deferred until needed, if this {@code AsynchronousInstrument} metric is not
      * exported then it will never be called.
      *
-     * @param callback the callback to be executed before export.
+     * @param updater the consumer to be executed before export.
      */
-    Builder<R> setCallback(Callback<R> callback);
+    Builder<R> setUpdater(Consumer<R> updater);
 
     @Override
     AsynchronousInstrument build();
@@ -42,12 +38,12 @@ public interface AsynchronousInstrument extends Instrument {
 
   interface Result {}
 
-  /** The result for the {@link Callback}. */
+  /** The result pass to the updater. */
   interface LongResult extends Result {
     void observe(long value, Labels labels);
   }
 
-  /** The result for the {@link Callback}. */
+  /** The result pass to the updater. */
   interface DoubleResult extends Result {
     void observe(double value, Labels labels);
   }
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DefaultMeter.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DefaultMeter.java
index 0977520cdd..b4b0204e4d 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DefaultMeter.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DefaultMeter.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.common.Labels;
 import io.opentelemetry.api.internal.StringUtils;
 import io.opentelemetry.api.internal.Utils;
 import java.util.Objects;
+import java.util.function.Consumer;
 import javax.annotation.concurrent.Immutable;
 import javax.annotation.concurrent.ThreadSafe;
 
@@ -429,8 +430,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public Builder setCallback(Callback<DoubleResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public Builder setUpdater(Consumer<DoubleResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
@@ -456,8 +457,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public NoopBuilder setCallback(Callback<LongResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public NoopBuilder setUpdater(Consumer<LongResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
@@ -483,8 +484,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public Builder setCallback(Callback<DoubleResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public Builder setUpdater(Consumer<DoubleResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
@@ -510,8 +511,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public Builder setCallback(Callback<LongResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public Builder setUpdater(Consumer<LongResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
@@ -537,8 +538,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public Builder setCallback(Callback<DoubleResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public Builder setUpdater(Consumer<DoubleResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
@@ -564,8 +565,8 @@ final class DefaultMeter implements Meter {
       }
 
       @Override
-      public Builder setCallback(Callback<LongResult> callback) {
-        Objects.requireNonNull(callback, "callback");
+      public Builder setUpdater(Consumer<LongResult> updater) {
+        Objects.requireNonNull(updater, "callback");
         return this;
       }
 
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleSumObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleSumObserver.java
index 59bdd46bea..f134886ef5 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleSumObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleSumObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -32,7 +33,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     cpuObserver.setCallback(
+ *     cpuObserver.setUpdater(
  *         new DoubleSumObserver.Callback<DoubleResult>() {
  *          {@literal @}Override
  *           public void update(DoubleResult result) {
@@ -57,7 +58,7 @@ public interface DoubleSumObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<DoubleResult> callback);
+    Builder setUpdater(Consumer<DoubleResult> updater);
 
     @Override
     DoubleSumObserver build();
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserver.java
index 21a38b575b..533465632c 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -32,7 +33,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     memoryObserver.setCallback(
+ *     memoryObserver.setUpdater(
  *         new DoubleUpDownSumObserver.Callback<DoubleResult>() {
  *          {@literal @}Override
  *           public void update(DoubleResult result) {
@@ -57,7 +58,7 @@ public interface DoubleUpDownSumObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<DoubleResult> callback);
+    Builder setUpdater(Consumer<DoubleResult> updater);
 
     @Override
     DoubleUpDownSumObserver build();
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleValueObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleValueObserver.java
index f7b0d204fa..c8320bebd7 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleValueObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/DoubleValueObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -29,7 +30,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     cpuObserver.setCallback(
+ *     cpuObserver.setUpdater(
  *         new DoubleValueObserver.Callback<DoubleResult>() {
  *          {@literal @}Override
  *           public void update(DoubleResult result) {
@@ -53,7 +54,7 @@ public interface DoubleValueObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<DoubleResult> callback);
+    Builder setUpdater(Consumer<DoubleResult> updater);
 
     @Override
     DoubleValueObserver build();
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongSumObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongSumObserver.java
index 7469716a0d..f44192ecd2 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongSumObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongSumObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -32,7 +33,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     cpuObserver.setCallback(
+ *     cpuObserver.setUpdater(
  *         new LongSumObserver.Callback<LongResult>() {
  *          {@literal @}Override
  *           public void update(LongResult result) {
@@ -57,7 +58,7 @@ public interface LongSumObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<LongResult> callback);
+    Builder setUpdater(Consumer<LongResult> updater);
 
     @Override
     LongSumObserver build();
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongUpDownSumObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongUpDownSumObserver.java
index 10c5b409e4..8c983170f1 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongUpDownSumObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongUpDownSumObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -32,7 +33,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     memoryObserver.setCallback(
+ *     memoryObserver.setUpdater(
  *         new LongUpDownSumObserver.Callback<LongResult>() {
  *          {@literal @}Override
  *           public void update(LongResult result) {
@@ -57,7 +58,7 @@ public interface LongUpDownSumObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<LongResult> callback);
+    Builder setUpdater(Consumer<LongResult> updater);
 
     @Override
     LongUpDownSumObserver build();
diff --git a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongValueObserver.java b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongValueObserver.java
index f0ce09bc3b..9b1d835c80 100644
--- a/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongValueObserver.java
+++ b/api/metrics/src/main/java/io/opentelemetry/api/metrics/LongValueObserver.java
@@ -5,6 +5,7 @@
 
 package io.opentelemetry.api.metrics;
 
+import java.util.function.Consumer;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -29,7 +30,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *           .build();
  *
  *   void init() {
- *     cpuObserver.setCallback(
+ *     cpuObserver.setUpdater(
  *         new LongValueObserver.Callback<LongResult>() {
  *          {@literal @}Override
  *           public void update(LongResult result) {
@@ -53,7 +54,7 @@ public interface LongValueObserver extends AsynchronousInstrument {
     Builder setUnit(String unit);
 
     @Override
-    Builder setCallback(Callback<LongResult> callback);
+    Builder setUpdater(Consumer<LongResult> updater);
 
     @Override
     LongValueObserver build();
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleSumObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleSumObserverTest.java
index f22382545c..dca0c7e53c 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleSumObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleSumObserverTest.java
@@ -67,7 +67,7 @@ class DoubleSumObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.doubleSumObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.doubleSumObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -77,7 +77,7 @@ class DoubleSumObserverTest {
         .doubleSumObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserverTest.java
index d6256c5ccc..7fe206e9a2 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleUpDownSumObserverTest.java
@@ -69,7 +69,7 @@ class DoubleUpDownSumObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.doubleUpDownSumObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.doubleUpDownSumObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -79,7 +79,7 @@ class DoubleUpDownSumObserverTest {
         .doubleUpDownSumObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleValueObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleValueObserverTest.java
index 34ccce069a..6bcf31ad99 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleValueObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/DoubleValueObserverTest.java
@@ -68,7 +68,7 @@ class DoubleValueObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.doubleValueObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.doubleValueObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -78,7 +78,7 @@ class DoubleValueObserverTest {
         .doubleValueObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongSumObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongSumObserverTest.java
index a4d89c9910..a26f42391f 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongSumObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongSumObserverTest.java
@@ -70,7 +70,7 @@ class LongSumObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.longSumObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.longSumObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -80,7 +80,7 @@ class LongSumObserverTest {
         .longSumObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongUpDownSumObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongUpDownSumObserverTest.java
index e9a5ba78a6..f0bd18e350 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongUpDownSumObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongUpDownSumObserverTest.java
@@ -71,7 +71,7 @@ class LongUpDownSumObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.longUpDownSumObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.longUpDownSumObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -81,7 +81,7 @@ class LongUpDownSumObserverTest {
         .longUpDownSumObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongValueObserverTest.java b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongValueObserverTest.java
index 6978cafaeb..eda3bcb15c 100644
--- a/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongValueObserverTest.java
+++ b/api/metrics/src/test/java/io/opentelemetry/api/metrics/LongValueObserverTest.java
@@ -72,7 +72,7 @@ class LongValueObserverTest {
   void preventNull_Callback() {
     assertThrows(
         NullPointerException.class,
-        () -> meter.longValueObserverBuilder("metric").setCallback(null).build(),
+        () -> meter.longValueObserverBuilder("metric").setUpdater(null).build(),
         "callback");
   }
 
@@ -82,7 +82,7 @@ class LongValueObserverTest {
         .longValueObserverBuilder(NAME)
         .setDescription(DESCRIPTION)
         .setUnit(UNIT)
-        .setCallback(result -> {})
+        .setUpdater(result -> {})
         .build();
   }
 }
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/AbstractAsynchronousInstrument.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/AbstractAsynchronousInstrument.java
index 4deaa31967..3493412701 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/AbstractAsynchronousInstrument.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/AbstractAsynchronousInstrument.java
@@ -12,18 +12,19 @@ import io.opentelemetry.sdk.metrics.data.MetricData;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 abstract class AbstractAsynchronousInstrument<T extends AsynchronousInstrument.Result>
     extends AbstractInstrument implements AsynchronousInstrument {
-  @Nullable private final Callback<T> metricUpdater;
+  @Nullable private final Consumer<T> metricUpdater;
   private final ReentrantLock collectLock = new ReentrantLock();
   private final InstrumentProcessor instrumentProcessor;
 
   AbstractAsynchronousInstrument(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<T> metricUpdater) {
+      @Nullable Consumer<T> metricUpdater) {
     super(descriptor);
     this.metricUpdater = metricUpdater;
     this.instrumentProcessor = instrumentProcessor;
@@ -36,7 +37,7 @@ abstract class AbstractAsynchronousInstrument<T extends AsynchronousInstrument.R
     }
     collectLock.lock();
     try {
-      metricUpdater.update(newResult(instrumentProcessor));
+      metricUpdater.accept(newResult(instrumentProcessor));
       return instrumentProcessor.completeCollectionCycle();
     } finally {
       collectLock.unlock();
@@ -60,7 +61,7 @@ abstract class AbstractAsynchronousInstrument<T extends AsynchronousInstrument.R
     AbstractLongAsynchronousInstrument(
         InstrumentDescriptor descriptor,
         InstrumentProcessor instrumentProcessor,
-        @Nullable Callback<LongResult> metricUpdater) {
+        @Nullable Consumer<LongResult> metricUpdater) {
       super(descriptor, instrumentProcessor, metricUpdater);
     }
 
@@ -91,7 +92,7 @@ abstract class AbstractAsynchronousInstrument<T extends AsynchronousInstrument.R
     AbstractDoubleAsynchronousInstrument(
         InstrumentDescriptor descriptor,
         InstrumentProcessor instrumentProcessor,
-        @Nullable Callback<DoubleResult> metricUpdater) {
+        @Nullable Consumer<DoubleResult> metricUpdater) {
       super(descriptor, instrumentProcessor, metricUpdater);
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdk.java
index 859309883f..7dd9f9acac 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.DoubleSumObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractDoubleAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class DoubleSumObserverSdk extends AbstractDoubleAsynchronousInstrument
@@ -17,7 +18,7 @@ final class DoubleSumObserverSdk extends AbstractDoubleAsynchronousInstrument
   DoubleSumObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<DoubleResult> metricUpdater) {
+      @Nullable Consumer<DoubleResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -25,7 +26,7 @@ final class DoubleSumObserverSdk extends AbstractDoubleAsynchronousInstrument
       extends AbstractAsynchronousInstrument.Builder<DoubleSumObserverSdk.Builder>
       implements DoubleSumObserver.Builder {
 
-    @Nullable private Callback<DoubleResult> callback;
+    @Nullable private Consumer<DoubleResult> callback;
 
     Builder(
         String name,
@@ -40,8 +41,8 @@ final class DoubleSumObserverSdk extends AbstractDoubleAsynchronousInstrument
     }
 
     @Override
-    public Builder setCallback(Callback<DoubleResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<DoubleResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdk.java
index d7d3aa7fdf..b6e38d7d46 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.DoubleUpDownSumObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractDoubleAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class DoubleUpDownSumObserverSdk extends AbstractDoubleAsynchronousInstrument
@@ -17,7 +18,7 @@ final class DoubleUpDownSumObserverSdk extends AbstractDoubleAsynchronousInstrum
   DoubleUpDownSumObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<DoubleResult> metricUpdater) {
+      @Nullable Consumer<DoubleResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -25,7 +26,7 @@ final class DoubleUpDownSumObserverSdk extends AbstractDoubleAsynchronousInstrum
       extends AbstractAsynchronousInstrument.Builder<DoubleUpDownSumObserverSdk.Builder>
       implements DoubleUpDownSumObserver.Builder {
 
-    @Nullable private Callback<DoubleResult> callback;
+    @Nullable private Consumer<DoubleResult> callback;
 
     Builder(
         String name,
@@ -40,8 +41,8 @@ final class DoubleUpDownSumObserverSdk extends AbstractDoubleAsynchronousInstrum
     }
 
     @Override
-    public Builder setCallback(Callback<DoubleResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<DoubleResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdk.java
index fe4abf1d9f..f4726821a8 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.DoubleValueObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractDoubleAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class DoubleValueObserverSdk extends AbstractDoubleAsynchronousInstrument
@@ -17,7 +18,7 @@ final class DoubleValueObserverSdk extends AbstractDoubleAsynchronousInstrument
   DoubleValueObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<DoubleResult> metricUpdater) {
+      @Nullable Consumer<DoubleResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -25,7 +26,7 @@ final class DoubleValueObserverSdk extends AbstractDoubleAsynchronousInstrument
       extends AbstractAsynchronousInstrument.Builder<DoubleValueObserverSdk.Builder>
       implements DoubleValueObserver.Builder {
 
-    @Nullable private Callback<DoubleResult> callback;
+    @Nullable private Consumer<DoubleResult> callback;
 
     Builder(
         String name,
@@ -40,8 +41,8 @@ final class DoubleValueObserverSdk extends AbstractDoubleAsynchronousInstrument
     }
 
     @Override
-    public Builder setCallback(Callback<DoubleResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<DoubleResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongSumObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongSumObserverSdk.java
index 5b3bf4be55..9a7364f92e 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongSumObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongSumObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.LongSumObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractLongAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class LongSumObserverSdk extends AbstractLongAsynchronousInstrument
@@ -16,7 +17,7 @@ final class LongSumObserverSdk extends AbstractLongAsynchronousInstrument
   LongSumObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<LongResult> metricUpdater) {
+      @Nullable Consumer<LongResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -24,7 +25,7 @@ final class LongSumObserverSdk extends AbstractLongAsynchronousInstrument
       extends AbstractAsynchronousInstrument.Builder<LongSumObserverSdk.Builder>
       implements LongSumObserver.Builder {
 
-    @Nullable private Callback<LongResult> callback;
+    @Nullable private Consumer<LongResult> callback;
 
     Builder(
         String name,
@@ -39,8 +40,8 @@ final class LongSumObserverSdk extends AbstractLongAsynchronousInstrument
     }
 
     @Override
-    public Builder setCallback(Callback<LongResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<LongResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdk.java
index fee2fd64c5..bfb009d329 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.LongUpDownSumObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractLongAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class LongUpDownSumObserverSdk extends AbstractLongAsynchronousInstrument
@@ -16,7 +17,7 @@ final class LongUpDownSumObserverSdk extends AbstractLongAsynchronousInstrument
   LongUpDownSumObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<LongResult> metricUpdater) {
+      @Nullable Consumer<LongResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -24,7 +25,7 @@ final class LongUpDownSumObserverSdk extends AbstractLongAsynchronousInstrument
       extends AbstractAsynchronousInstrument.Builder<LongUpDownSumObserverSdk.Builder>
       implements LongUpDownSumObserver.Builder {
 
-    @Nullable private Callback<LongResult> callback;
+    @Nullable private Consumer<LongResult> callback;
 
     Builder(
         String name,
@@ -39,8 +40,8 @@ final class LongUpDownSumObserverSdk extends AbstractLongAsynchronousInstrument
     }
 
     @Override
-    public Builder setCallback(Callback<LongResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<LongResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongValueObserverSdk.java b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongValueObserverSdk.java
index f9da1e7bb3..5ee7601a2b 100644
--- a/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongValueObserverSdk.java
+++ b/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/LongValueObserverSdk.java
@@ -9,6 +9,7 @@ import io.opentelemetry.api.metrics.LongValueObserver;
 import io.opentelemetry.sdk.metrics.AbstractAsynchronousInstrument.AbstractLongAsynchronousInstrument;
 import io.opentelemetry.sdk.metrics.common.InstrumentType;
 import io.opentelemetry.sdk.metrics.common.InstrumentValueType;
+import java.util.function.Consumer;
 import javax.annotation.Nullable;
 
 final class LongValueObserverSdk extends AbstractLongAsynchronousInstrument
@@ -17,7 +18,7 @@ final class LongValueObserverSdk extends AbstractLongAsynchronousInstrument
   LongValueObserverSdk(
       InstrumentDescriptor descriptor,
       InstrumentProcessor instrumentProcessor,
-      @Nullable Callback<LongResult> metricUpdater) {
+      @Nullable Consumer<LongResult> metricUpdater) {
     super(descriptor, instrumentProcessor, metricUpdater);
   }
 
@@ -25,7 +26,7 @@ final class LongValueObserverSdk extends AbstractLongAsynchronousInstrument
       extends AbstractAsynchronousInstrument.Builder<LongValueObserverSdk.Builder>
       implements LongValueObserver.Builder {
 
-    @Nullable private Callback<LongResult> callback;
+    @Nullable private Consumer<LongResult> callback;
 
     Builder(
         String name,
@@ -40,8 +41,8 @@ final class LongValueObserverSdk extends AbstractLongAsynchronousInstrument
     }
 
     @Override
-    public Builder setCallback(Callback<LongResult> callback) {
-      this.callback = callback;
+    public Builder setUpdater(Consumer<LongResult> updater) {
+      this.callback = updater;
       return this;
     }
 
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdkTest.java
index 2381caa602..9afe1bae57 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleSumObserverSdkTest.java
@@ -50,7 +50,7 @@ class DoubleSumObserverSdkTest {
             .doubleSumObserverBuilder("testObserver")
             .setDescription("My own DoubleSumObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(doubleSumObserver.collectAll())
         .containsExactly(
@@ -69,7 +69,7 @@ class DoubleSumObserverSdkTest {
     DoubleSumObserverSdk doubleSumObserver =
         testSdk
             .doubleSumObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12.1d, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12.1d, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(doubleSumObserver.collectAll())
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdkTest.java
index 81e7f5eec3..164ccf45f9 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleUpDownSumObserverSdkTest.java
@@ -50,7 +50,7 @@ class DoubleUpDownSumObserverSdkTest {
             .doubleUpDownSumObserverBuilder("testObserver")
             .setDescription("My own DoubleUpDownSumObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(doubleUpDownSumObserver.collectAll())
         .containsExactly(
@@ -69,7 +69,7 @@ class DoubleUpDownSumObserverSdkTest {
     DoubleUpDownSumObserverSdk doubleUpDownSumObserver =
         testSdk
             .doubleUpDownSumObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12.1d, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12.1d, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(doubleUpDownSumObserver.collectAll())
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdkTest.java
index b52e030688..76e5369dd4 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/DoubleValueObserverSdkTest.java
@@ -51,7 +51,7 @@ class DoubleValueObserverSdkTest {
             .doubleValueObserverBuilder("testObserver")
             .setDescription("My own DoubleValueObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(doubleValueObserver.collectAll())
         .containsExactly(
@@ -70,7 +70,7 @@ class DoubleValueObserverSdkTest {
     DoubleValueObserverSdk doubleValueObserver =
         testSdk
             .doubleValueObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12.1d, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12.1d, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(doubleValueObserver.collectAll())
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongSumObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongSumObserverSdkTest.java
index 9b65fdafca..e2ab071b7e 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongSumObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongSumObserverSdkTest.java
@@ -50,7 +50,7 @@ class LongSumObserverSdkTest {
             .longSumObserverBuilder("testObserver")
             .setDescription("My own LongSumObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(longSumObserver.collectAll())
         .containsExactly(
@@ -69,7 +69,7 @@ class LongSumObserverSdkTest {
     LongSumObserverSdk longSumObserver =
         testSdk
             .longSumObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(longSumObserver.collectAll())
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdkTest.java
index a5fef12cf8..e8ca84dfba 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongUpDownSumObserverSdkTest.java
@@ -50,7 +50,7 @@ class LongUpDownSumObserverSdkTest {
             .longUpDownSumObserverBuilder("testObserver")
             .setDescription("My own LongUpDownSumObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(longUpDownSumObserver.collectAll())
         .containsExactly(
@@ -69,7 +69,7 @@ class LongUpDownSumObserverSdkTest {
     LongUpDownSumObserverSdk longUpDownSumObserver =
         testSdk
             .longUpDownSumObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(longUpDownSumObserver.collectAll())
diff --git a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongValueObserverSdkTest.java b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongValueObserverSdkTest.java
index 8b4bcc89e3..1f584fb180 100644
--- a/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongValueObserverSdkTest.java
+++ b/sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/LongValueObserverSdkTest.java
@@ -50,7 +50,7 @@ class LongValueObserverSdkTest {
             .longValueObserverBuilder("testObserver")
             .setDescription("My own LongValueObserver")
             .setUnit("ms")
-            .setCallback(result -> {})
+            .setUpdater(result -> {})
             .build();
     assertThat(longValueObserver.collectAll())
         .containsExactly(
@@ -69,7 +69,7 @@ class LongValueObserverSdkTest {
     LongValueObserverSdk longValueObserver =
         testSdk
             .longValueObserverBuilder("testObserver")
-            .setCallback(result -> result.observe(12, Labels.of("k", "v")))
+            .setUpdater(result -> result.observe(12, Labels.of("k", "v")))
             .build();
     testClock.advanceNanos(SECOND_NANOS);
     assertThat(longValueObserver.collectAll())
diff --git a/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessor.java b/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessor.java
index 791037b3ff..a97db6550b 100644
--- a/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessor.java
+++ b/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessor.java
@@ -167,7 +167,7 @@ public final class BatchSpanProcessor implements SpanProcessor {
           .longValueObserverBuilder("queueSize")
           .setDescription("The number of spans queued")
           .setUnit("1")
-          .setCallback(
+          .setUpdater(
               result ->
                   result.observe(
                       queue.size(),