diff --git a/core/common/src/main/scala/org/typelevel/otel4s/TextMapPropagator.scala b/core/common/src/main/scala/org/typelevel/otel4s/TextMapPropagator.scala
index 0113bc782..cd9ef1268 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/TextMapPropagator.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/TextMapPropagator.scala
@@ -85,7 +85,7 @@ trait TextMapPropagator[F[_]] {
     * @return
     *   a copy of the carrier, with new fields injected
     */
-  def injected[A: TextMapInjector](ctx: Vault, carrier: A): A
+  def injected[A: TextMapUpdater](ctx: Vault, carrier: A): A
 }
 
 object TextMapPropagator {
@@ -100,7 +100,7 @@ object TextMapPropagator {
       def inject[A: TextMapSetter](ctx: Vault, carrier: A): F[Unit] =
         Applicative[F].unit
 
-      def injected[A: TextMapInjector](ctx: Vault, carrier: A): A =
+      def injected[A: TextMapUpdater](ctx: Vault, carrier: A): A =
         carrier
     }
 }
diff --git a/core/common/src/main/scala/org/typelevel/otel4s/TextMapInjector.scala b/core/common/src/main/scala/org/typelevel/otel4s/TextMapUpdater.scala
similarity index 79%
rename from core/common/src/main/scala/org/typelevel/otel4s/TextMapInjector.scala
rename to core/common/src/main/scala/org/typelevel/otel4s/TextMapUpdater.scala
index 126a85914..2a41f88d7 100644
--- a/core/common/src/main/scala/org/typelevel/otel4s/TextMapInjector.scala
+++ b/core/common/src/main/scala/org/typelevel/otel4s/TextMapUpdater.scala
@@ -16,12 +16,6 @@
 
 package org.typelevel.otel4s
 
-trait TextMapInjector[A] {
-  type Builder
-
-  def textMapSetter: TextMapSetter[Builder]
-
-  def toBuilder(carrier: A): Builder
-
-  def toCarrier(builder: Builder): A
+trait TextMapUpdater[A] {
+  def updated(carrier: A, key: String, value: String): A
 }
diff --git a/java/common/src/main/scala/org/typelevel/otel4s/java/TextMapPropagatorImpl.scala b/java/common/src/main/scala/org/typelevel/otel4s/java/TextMapPropagatorImpl.scala
index afc5b6026..270f0490a 100644
--- a/java/common/src/main/scala/org/typelevel/otel4s/java/TextMapPropagatorImpl.scala
+++ b/java/common/src/main/scala/org/typelevel/otel4s/java/TextMapPropagatorImpl.scala
@@ -41,14 +41,16 @@ private[java] class TextMapPropagatorImpl[F[_]: Sync](
     )
 
   def injected[A](ctx: Vault, carrier: A)(implicit
-      injector: TextMapInjector[A]
+      injector: TextMapUpdater[A]
   ): A = {
-    val builder = injector.toBuilder(carrier)
-    jPropagator.inject(
+    var injectedCarrier = carrier
+    jPropagator.inject[Null](
       toJContext(ctx),
-      builder,
-      fromTextMapSetter(injector.textMapSetter)
+      null, // explicitly allowed per opentelemetry-java, so our setter can be a lambda!
+      (_, key, value) => {
+        injectedCarrier = injector.updated(injectedCarrier, key, value)
+      }
     )
-    injector.toCarrier(builder)
+    injectedCarrier
   }
 }