diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
index 20cc188e80..45e0d7afdf 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
@@ -6,7 +6,7 @@ package akka.actor.typed.javadsl
 
 import scala.annotation.tailrec
 
-import akka.japi.function.Function
+import akka.japi.function.{ Function => JFunction }
 import akka.japi.function.Creator
 import akka.japi.function.{ Predicate => JPredicate }
 import akka.annotation.InternalApi
@@ -43,7 +43,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
    * @tparam M type of message to match
    * @return a new behavior builder with the specified handling appended
    */
-  def onMessage[M <: T](`type`: Class[M], handler: Function[M, Behavior[T]]): BehaviorBuilder[T] =
+  def onMessage[M <: T](`type`: Class[M], handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] =
     withMessage(OptionVal.Some(`type`), OptionVal.None, handler)
 
   /**
@@ -55,7 +55,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
    * @tparam M type of message to match
    * @return a new behavior builder with the specified handling appended
    */
-  def onMessage[M <: T](`type`: Class[M], test: JPredicate[M], handler: Function[M, Behavior[T]]): BehaviorBuilder[T] =
+  def onMessage[M <: T](`type`: Class[M], test: JPredicate[M], handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] =
     withMessage(OptionVal.Some(`type`), OptionVal.Some((t: T) => test.test(t.asInstanceOf[M])), handler)
 
   /**
@@ -68,7 +68,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
    * @param handler action to apply when the type matches
    * @return a new behavior builder with the specified handling appended
    */
-  def onMessageUnchecked[M <: T](`type`: Class[_ <: T], handler: Function[M, Behavior[T]]): BehaviorBuilder[T] =
+  def onMessageUnchecked[M <: T](`type`: Class[_ <: T], handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] =
     withMessage[M](OptionVal.Some(`type`.asInstanceOf[Class[M]]), OptionVal.None, handler)
 
   /**
@@ -91,7 +91,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
    * @param handler action to apply for any message
    * @return a new behavior builder with the specified handling appended
    */
-  def onAnyMessage(handler: Function[T, Behavior[T]]): BehaviorBuilder[T] =
+  def onAnyMessage(handler: JFunction[T, Behavior[T]]): BehaviorBuilder[T] =
     withMessage(OptionVal.None, OptionVal.None, handler)
 
   /**
@@ -102,8 +102,8 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
    * @tparam M type of signal to match
    * @return a new behavior builder with the specified handling appended
    */
-  def onSignal[M <: Signal](`type`: Class[M], handler: Function[M, Behavior[T]]): BehaviorBuilder[T] =
-    withSignal(`type`, OptionVal.None, handler.asInstanceOf[Function[Signal, Behavior[T]]])
+  def onSignal[M <: Signal](`type`: Class[M], handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] =
+    withSignal(`type`, OptionVal.None, handler.asInstanceOf[JFunction[Signal, Behavior[T]]])
 
   /**
    * Add a new predicated case to the signal handling.
@@ -117,11 +117,11 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
   def onSignal[M <: Signal](
       `type`: Class[M],
       test: JPredicate[M],
-      handler: Function[M, Behavior[T]]): BehaviorBuilder[T] =
+      handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] =
     withSignal(
       `type`,
       OptionVal.Some((t: Signal) => test.test(t.asInstanceOf[M])),
-      handler.asInstanceOf[Function[Signal, Behavior[T]]])
+      handler.asInstanceOf[JFunction[Signal, Behavior[T]]])
 
   /**
    * Add a new case to the signal handling matching equal signals.
@@ -136,7 +136,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
   private def withMessage[M <: T](
       clazz: OptionVal[Class[M]],
       test: OptionVal[M => Boolean],
-      handler: Function[M, Behavior[T]]): BehaviorBuilder[T] = {
+      handler: JFunction[M, Behavior[T]]): BehaviorBuilder[T] = {
     val newCase = Case(clazz, test, handler)
     new BehaviorBuilder[T](newCase.asInstanceOf[Case[T, T]] +: messageHandlers, signalHandlers)
   }
@@ -144,7 +144,7 @@ final class BehaviorBuilder[T] private (messageHandlers: List[Case[T, T]], signa
   private def withSignal[M <: Signal](
       `type`: Class[M],
       test: OptionVal[Signal => Boolean],
-      handler: Function[Signal, Behavior[T]]): BehaviorBuilder[T] = {
+      handler: JFunction[Signal, Behavior[T]]): BehaviorBuilder[T] = {
     new BehaviorBuilder[T](
       messageHandlers,
       Case(OptionVal.Some(`type`), test, handler).asInstanceOf[Case[T, Signal]] +: signalHandlers)
@@ -161,7 +161,7 @@ object BehaviorBuilder {
   private[javadsl] final case class Case[BT, MT](
       `type`: OptionVal[Class[_ <: MT]],
       test: OptionVal[MT => Boolean],
-      handler: Function[MT, Behavior[BT]])
+      handler: JFunction[MT, Behavior[BT]])
 
   /**
    * @return new empty immutable behavior builder.