diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorCompile.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorCompile.java
index 0c25b27ff1..47937f7807 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorCompile.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorCompile.java
@@ -33,8 +33,8 @@ public class ActorCompile {
     }
   }
 
-  Behavior<MyMsg> actor1 = immutable((ctx, msg) -> stopped(), (ctx, signal) -> same());
-  Behavior<MyMsg> actor2 = immutable((ctx, msg) -> unhandled());
+  Behavior<MyMsg> actor1 = Behaviors.receive((ctx, msg) -> stopped(), (ctx, signal) -> same());
+  Behavior<MyMsg> actor2 = Behaviors.receive((ctx, msg) -> unhandled());
   Behavior<MyMsg> actor4 = empty();
   Behavior<MyMsg> actor5 = ignore();
   Behavior<MyMsg> actor6 = tap((ctx, signal) -> {}, (ctx, msg) -> {}, actor5);
@@ -44,14 +44,14 @@ public class ActorCompile {
     return monitor(self, ignore());
   });
   Behavior<MyMsg> actor9 = widened(actor7, pf -> pf.match(MyMsgA.class, x -> x));
-  Behavior<MyMsg> actor10 = immutable((ctx, msg) -> stopped(actor4), (ctx, signal) -> same());
+  Behavior<MyMsg> actor10 = Behaviors.receive((ctx, msg) -> stopped(actor4), (ctx, signal) -> same());
 
   ActorSystem<MyMsg> system = ActorSystem.create(actor1, "Sys");
 
   {
-    Behaviors.<MyMsg>immutable((ctx, msg) -> {
+    Behaviors.<MyMsg>receive((ctx, msg) -> {
       if (msg instanceof MyMsgA) {
-        return immutable((ctx2, msg2) -> {
+        return Behaviors.receive((ctx2, msg2) -> {
           if (msg2 instanceof MyMsgB) {
             ((MyMsgA) msg).replyTo.tell(((MyMsgB) msg2).greeting);
 
@@ -79,7 +79,7 @@ public class ActorCompile {
     }
 
     @Override
-    public Behavior<MyMsg> receiveMessage(ActorContext<MyMsg> ctx, MyMsg msg) throws Exception {
+    public Behavior<MyMsg> receive(ActorContext<MyMsg> ctx, MyMsg msg) throws Exception {
       ActorRef<String> adapter = ctx.asJava().messageAdapter(String.class, s -> new MyMsgB(s.toUpperCase()));
       return this;
     }
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorContextAskTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorContextAskTest.java
index f28afd81ff..8c7474d7ff 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorContextAskTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorContextAskTest.java
@@ -6,7 +6,6 @@ package akka.actor.typed.javadsl;
 
 import akka.actor.typed.ActorRef;
 import akka.actor.typed.Behavior;
-import akka.testkit.AkkaJUnitActorSystemResource;
 import akka.testkit.AkkaSpec;
 import akka.testkit.typed.javadsl.TestKitJunitResource;
 import akka.testkit.typed.javadsl.TestProbe;
@@ -32,7 +31,7 @@ public class ActorContextAskTest extends JUnitSuite {
 
   @Test
   public void provideASafeAsk() {
-    final Behavior<Ping> pingPongBehavior = Behaviors.immutable((ActorContext<Ping> context, Ping message) -> {
+    final Behavior<Ping> pingPongBehavior = Behaviors.receive((ActorContext<Ping> context, Ping message) -> {
       message.respondTo.tell(new Pong());
       return Behaviors.same();
     });
@@ -50,7 +49,7 @@ public class ActorContextAskTest extends JUnitSuite {
             else return exception;
           });
 
-      return Behaviors.immutable((ActorContext<Object> context, Object message) -> {
+      return Behaviors.receive((ActorContext<Object> context, Object message) -> {
         probe.ref().tell(message);
         return Behaviors.same();
       });
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorLoggingTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorLoggingTest.java
index a7b0ee8155..8313771626 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorLoggingTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ActorLoggingTest.java
@@ -51,7 +51,7 @@ public class ActorLoggingTest extends JUnitSuite {
         mdc.put("txId", msg.getTransactionId());
         return mdc;
       },
-      Behaviors.immutable(Protocol.class)
+      Behaviors.receive(Protocol.class)
         .onMessage(Message.class, (ctx, msg) -> {
           ctx.getLog().info(msg.toString());
           return Behaviors.same();
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/AdapterTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/AdapterTest.java
index ad18b8e5d9..a66cc0d2da 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/AdapterTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/AdapterTest.java
@@ -50,7 +50,7 @@ public class AdapterTest extends JUnitSuite {
 
     static Behavior<String> create(akka.actor.ActorRef ref, akka.actor.ActorRef probe) {
       Typed1 logic = new Typed1(ref, probe);
-      return immutable(
+      return receive(
           (ctx, msg) -> logic.onMessage(ctx, msg),
           (ctx, sig) -> logic.onSignal(ctx, sig));
     }
@@ -187,7 +187,7 @@ public class AdapterTest extends JUnitSuite {
   }
 
   static Behavior<Typed2Msg> typed2() {
-      return Behaviors.immutable((ctx, msg) -> {
+      return Behaviors.receive((ctx, msg) -> {
         if (msg instanceof Ping) {
           ActorRef<String> replyTo = ((Ping) msg).replyTo;
           replyTo.tell("pong");
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/BehaviorBuilderTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/BehaviorBuilderTest.java
index 17b364d0e5..40dc219122 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/BehaviorBuilderTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/BehaviorBuilderTest.java
@@ -33,7 +33,7 @@ public class BehaviorBuilderTest extends JUnitSuite {
 
     @Test
     public void shouldCompile() {
-      Behavior<Message> b = Behaviors.immutable(Message.class)
+      Behavior<Message> b = Behaviors.receive(Message.class)
         .onMessage(One.class, (ctx, o) -> {
           o.foo();
           return same();
@@ -66,7 +66,7 @@ public class BehaviorBuilderTest extends JUnitSuite {
     }
 
     public Behavior<CounterMessage> immutableCounter(int currentValue) {
-      return Behaviors.immutable(CounterMessage.class)
+      return Behaviors.receive(CounterMessage.class)
           .onMessage(Increase.class, (ctx, o) -> {
             return immutableCounter(currentValue + 1);
           })
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ReceiveBuilderTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ReceiveBuilderTest.java
index 9d0f5c0fa0..20c7a94688 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ReceiveBuilderTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/ReceiveBuilderTest.java
@@ -18,7 +18,7 @@ public class ReceiveBuilderTest extends JUnitSuite {
 
   @Test
   public void testMutableCounter() {
-    Behavior<BehaviorBuilderTest.CounterMessage> mutable = Behaviors.mutable(ctx -> new Behaviors.MutableBehavior<BehaviorBuilderTest.CounterMessage>() {
+    Behavior<BehaviorBuilderTest.CounterMessage> mutable = Behaviors.setup(ctx -> new MutableBehavior<BehaviorBuilderTest.CounterMessage>() {
       int currentValue = 0;
 
       private Behavior<BehaviorBuilderTest.CounterMessage> receiveIncrease(BehaviorBuilderTest.Increase msg) {
@@ -41,7 +41,7 @@ public class ReceiveBuilderTest extends JUnitSuite {
     });
   }
 
-  private static class MyMutableBehavior extends Behaviors.MutableBehavior<BehaviorBuilderTest.CounterMessage> {
+  private static class MyMutableBehavior extends MutableBehavior<BehaviorBuilderTest.CounterMessage> {
     private int value;
 
     public MyMutableBehavior(int initialValue) {
@@ -59,6 +59,6 @@ public class ReceiveBuilderTest extends JUnitSuite {
   @Test
   public void testInitializationOrder() throws Exception {
     MyMutableBehavior mutable = new MyMutableBehavior(42);
-    assertEquals(Behaviors.unhandled(), mutable.receiveMessage(null, new BehaviorBuilderTest.Increase()));
+    assertEquals(Behaviors.unhandled(), mutable.receive(null, new BehaviorBuilderTest.Increase()));
   }
 }
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/WatchTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/WatchTest.java
index c5574ddfab..ead701649a 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/WatchTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/javadsl/WatchTest.java
@@ -8,11 +8,9 @@ import java.util.concurrent.CompletionStage;
 import java.util.concurrent.TimeUnit;
 
 import akka.Done;
-import akka.testkit.AkkaSpec;
 import akka.testkit.typed.javadsl.TestKitJunitResource;
 import org.junit.ClassRule;
 import org.scalatest.junit.JUnitSuite;
-import scala.concurrent.Await;
 import scala.concurrent.duration.Duration;
 import akka.util.Timeout;
 import org.junit.Test;
@@ -45,13 +43,13 @@ public class WatchTest extends JUnitSuite {
   // final FiniteDuration fiveSeconds = FiniteDuration.create(5, TimeUnit.SECONDS);
   final Timeout timeout = new Timeout(Duration.create(5, TimeUnit.SECONDS));
 
-  final Behavior<Stop> exitingActor = immutable((ctx, msg) -> {
+  final Behavior<Stop> exitingActor = receive((ctx, msg) -> {
     System.out.println("Stopping!");
     return stopped();
   });
 
   private Behavior<RunTest> waitingForTermination(ActorRef<Done> replyWhenTerminated) {
-    return immutable(
+    return receive(
       (ctx, msg) -> unhandled(),
       (ctx, sig) -> {
         if (sig instanceof Terminated) {
@@ -63,7 +61,7 @@ public class WatchTest extends JUnitSuite {
   }
 
   private Behavior<Message> waitingForMessage(ActorRef<Done> replyWhenReceived) {
-    return immutable(
+    return receive(
       (ctx, msg) -> {
         if (msg instanceof CustomTerminationMessage) {
           replyWhenReceived.tell(Done.getInstance());
@@ -77,7 +75,7 @@ public class WatchTest extends JUnitSuite {
 
   @Test
   public void shouldWatchTerminatingActor() throws Exception {
-    Behavior<RunTest> exiting = Behaviors.immutable(RunTest.class)
+    Behavior<RunTest> exiting = Behaviors.receive(RunTest.class)
       .onMessage(RunTest.class, (ctx, msg) -> {
         ActorRef<Stop> watched = ctx.spawn(exitingActor, "exitingActor");
         ctx.watch(watched);
@@ -92,7 +90,7 @@ public class WatchTest extends JUnitSuite {
 
   @Test
   public void shouldWatchWithCustomMessage() throws Exception {
-    Behavior<Message> exiting = Behaviors.immutable(Message.class)
+    Behavior<Message> exiting = Behaviors.receive(Message.class)
       .onMessage(RunTest.class, (ctx, msg) -> {
         ActorRef<Stop> watched = ctx.spawn(exitingActor, "exitingActor");
         ctx.watchWith(watched, new CustomTerminationMessage());
diff --git a/akka-actor-typed-tests/src/test/java/akka/actor/typed/receptionist/ReceptionistApiTest.java b/akka-actor-typed-tests/src/test/java/akka/actor/typed/receptionist/ReceptionistApiTest.java
index f0cc6bfe56..fcfde83b34 100644
--- a/akka-actor-typed-tests/src/test/java/akka/actor/typed/receptionist/ReceptionistApiTest.java
+++ b/akka-actor-typed-tests/src/test/java/akka/actor/typed/receptionist/ReceptionistApiTest.java
@@ -84,7 +84,7 @@ public class ReceptionistApiTest {
       // to cover as much of the API as possible
       ctx.getSystem().receptionist().tell(Receptionist.register(key, ctx.getSelf().narrow(), ctx.getSelf().narrow()));
 
-      return Behaviors.immutable(Object.class)
+      return Behaviors.receive(Object.class)
         // matching is done best using the predicate version
         .onMessage(Receptionist.Listing.class, listing -> listing.isForKey(key), (msgCtx, listing) -> {
           Set<ActorRef<String>> services = listing.getServiceInstances(key);
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/FaultToleranceDocTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/FaultToleranceDocTest.java
index fc03b53446..b896a2df3d 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/FaultToleranceDocTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/FaultToleranceDocTest.java
@@ -26,7 +26,7 @@ public class FaultToleranceDocTest extends JUnitSuite {
   @Test
   public void bubblingSample() {
     // #bubbling-example
-    final Behavior<Message> failingChildBehavior = Behaviors.immutable(Message.class)
+    final Behavior<Message> failingChildBehavior = Behaviors.receive(Message.class)
       .onMessage(Fail.class, (ctx, message) -> {
         throw new RuntimeException(message.text);
       })
@@ -42,7 +42,7 @@ public class FaultToleranceDocTest extends JUnitSuite {
       // here we don't handle Terminated at all which means that
       // when the child fails or stops gracefully this actor will
       // fail with a DeathWatchException
-      return Behaviors.immutable(Message.class)
+      return Behaviors.receive(Message.class)
         .onMessage(Message.class, (innerCtx, msg) -> {
           // just pass messages on to the child
           child.tell(msg);
@@ -58,7 +58,7 @@ public class FaultToleranceDocTest extends JUnitSuite {
       // here we don't handle Terminated at all which means that
       // when middle management fails with a DeathWatchException
       // this actor will also fail
-      return Behaviors.immutable(Message.class)
+      return Behaviors.receive(Message.class)
         .onMessage(Message.class, (innerCtx, msg) -> {
           // just pass messages on to the child
           middleManagement.tell(msg);
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/GracefulStopDocTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/GracefulStopDocTest.java
index 2ba4f42f52..870fa7f645 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/GracefulStopDocTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/GracefulStopDocTest.java
@@ -42,7 +42,7 @@ public class GracefulStopDocTest {
       }
     }
 
-    public static final Behavior<JobControlLanguage> mcpa = Behaviors.immutable(JobControlLanguage.class)
+    public static final Behavior<JobControlLanguage> mcpa = Behaviors.receive(JobControlLanguage.class)
         .onMessage(SpawnJob.class, (ctx, msg) -> {
           ctx.getSystem().log().info("Spawning job {}!", msg.name);
           ctx.spawn(Job.job(msg.name), msg.name);
@@ -57,7 +57,7 @@ public class GracefulStopDocTest {
 
           // perform graceful stop, executing cleanup before final system termination
           // behavior executing cleanup is passed as a parameter to Actor.stopped
-          return Behaviors.stopped(Behaviors.onSignal((context, PostStop) -> {
+          return Behaviors.stopped(Behaviors.receiveSignal((context, PostStop) -> {
             context.getSystem().log().info("Cleanup!");
             return Behaviors.same();
           }));
@@ -92,7 +92,7 @@ public class GracefulStopDocTest {
 
   public static class Job {
     public static Behavior<JobControl.JobControlLanguage> job(String name) {
-      return Behaviors.onSignal((ctx, PostStop) -> {
+      return Behaviors.receiveSignal((ctx, PostStop) -> {
         ctx.getSystem().log().info("Worker {} stopped", name);
         return Behaviors.same();
       });
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/InteractionPatternsTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/InteractionPatternsTest.java
index 2d2540ae5b..e1465e2060 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/InteractionPatternsTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/InteractionPatternsTest.java
@@ -32,7 +32,7 @@ public class InteractionPatternsTest extends JUnitSuite {
     }
   }
 
-  static final Behavior<PrintMe> printerBehavior = Behaviors.immutable(PrintMe.class)
+  static final Behavior<PrintMe> printerBehavior = Behaviors.receive(PrintMe.class)
     .onMessage(PrintMe.class, (ctx, printMe) -> {
       ctx.getLog().info(printMe.message);
       return Behaviors.same();
@@ -61,7 +61,7 @@ public class InteractionPatternsTest extends JUnitSuite {
 
     // #request-response-respond
     // actor behavior
-    Behaviors.immutable(Request.class)
+    Behaviors.receive(Request.class)
       .onMessage(Request.class, (ctx, request) -> {
         // ... process request ...
         request.respondTo.tell(new Response("Here's your response!"));
@@ -170,7 +170,7 @@ public class InteractionPatternsTest extends JUnitSuite {
       }
     }
 
-    public static class Translator extends Behaviors.MutableBehavior<Command> {
+    public static class Translator extends MutableBehavior<Command> {
       private final ActorContext<Command> ctx;
       private final ActorRef<Backend.Request> backend;
       private final ActorRef<Backend.Response> backendResponseAdapter;
@@ -290,7 +290,7 @@ public class InteractionPatternsTest extends JUnitSuite {
 
   private static Behavior<Msg> idle(TimerScheduler<Msg> timers, ActorRef<Batch> target,
                                     FiniteDuration after, int maxSize) {
-    return Behaviors.immutable(Msg.class)
+    return Behaviors.receive(Msg.class)
       .onMessage(Msg.class, (ctx, msg) -> {
         timers.startSingleTimer(TIMER_KEY, new TimeoutMsg(), after);
         List<Msg> buffer = new ArrayList<>();
@@ -302,7 +302,7 @@ public class InteractionPatternsTest extends JUnitSuite {
 
   private static Behavior<Msg> active(List<Msg> buffer, TimerScheduler<Msg> timers,
                                       ActorRef<Batch> target, FiniteDuration after, int maxSize) {
-    return Behaviors.immutable(Msg.class)
+    return Behaviors.receive(Msg.class)
       .onMessage(TimeoutMsg.class, (ctx, msg) -> {
         target.tell(new Batch(buffer));
         return idle(timers, target, after, maxSize);
@@ -359,7 +359,7 @@ public class InteractionPatternsTest extends JUnitSuite {
   }
 
   static final Behavior<HalCommand> halBehavior =
-    Behaviors.immutable(HalCommand.class)
+    Behaviors.receive(HalCommand.class)
       .onMessage(OpenThePodBayDoorsPlease.class, (ctx, msg) -> {
         msg.respondTo.tell(new HalResponse("I'm sorry, Dave. I'm afraid I can't do that."));
         return Behaviors.same();
@@ -417,7 +417,7 @@ public class InteractionPatternsTest extends JUnitSuite {
           }
         });
 
-      return Behaviors.immutable(DaveProtocol.class)
+      return Behaviors.receive(DaveProtocol.class)
         // the adapted message ends up being processed like any other
         // message sent to the actor
         .onMessage(AdaptedResponse.class, (innerCtx, response) -> {
@@ -511,7 +511,7 @@ public class InteractionPatternsTest extends JUnitSuite {
       final ActorRef<GetKeys> keyCabinet = ctx.spawn(keyCabinetBehavior, "key-cabinet");
       final ActorRef<GetWallet> drawer = ctx.spawn(drawerBehavior, "drawer");
 
-      return Behaviors.immutable(HomeCommand.class)
+      return Behaviors.receive(HomeCommand.class)
         .onMessage(LeaveHome.class, (innerCtx, msg) -> {
           ctx.spawn(new PrepareToLeaveHome(msg.who, msg.respondTo, keyCabinet, drawer), "leaving" + msg.who);
           return Behavior.same();
@@ -520,7 +520,7 @@ public class InteractionPatternsTest extends JUnitSuite {
   }
 
   // per session actor behavior
-  class PrepareToLeaveHome extends Behaviors.MutableBehavior<Object> {
+  class PrepareToLeaveHome extends MutableBehavior<Object> {
     private final String whoIsLeaving;
     private final ActorRef<ReadyToLeaveHome> respondTo;
     private final ActorRef<GetKeys> keyCabinet;
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
index 64e7afe741..5785bd7f21 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
@@ -48,7 +48,7 @@ public class IntroTest {
       }
     }
 
-    public static final Behavior<Greet> greeter = Behaviors.immutable((ctx, msg) -> {
+    public static final Behavior<Greet> greeter = Behaviors.receive((ctx, msg) -> {
       System.out.println("Hello " + msg.whom + "!");
       msg.replyTo.tell(new Greeted(msg.whom));
       return Behaviors.same();
@@ -141,7 +141,7 @@ public class IntroTest {
     }
 
     private static Behavior<RoomCommand> chatRoom(List<ActorRef<SessionCommand>> sessions) {
-      return Behaviors.immutable(RoomCommand.class)
+      return Behaviors.receive(RoomCommand.class)
         .onMessage(GetSession.class, (ctx, getSession) -> {
           ActorRef<SessionEvent> client = getSession.replyTo;
           ActorRef<SessionCommand> ses = ctx.spawn(
@@ -166,7 +166,7 @@ public class IntroTest {
         ActorRef<RoomCommand> room,
         String screenName,
         ActorRef<SessionEvent> client) {
-      return Behaviors.immutable(ChatRoom.SessionCommand.class)
+      return Behaviors.receive(ChatRoom.SessionCommand.class)
           .onMessage(PostMessage.class, (ctx, post) -> {
             // from client, publish to others via the room
             room.tell(new PublishSessionMessage(screenName, post.message));
@@ -190,7 +190,7 @@ public class IntroTest {
     }
 
     public static Behavior<ChatRoom.SessionEvent> behavior() {
-      return Behaviors.immutable(ChatRoom.SessionEvent.class)
+      return Behaviors.receive(ChatRoom.SessionEvent.class)
         .onMessage(ChatRoom.SessionDenied.class, (ctx, msg) -> {
           System.out.println("cannot start chat room session: " + msg.reason);
           return Behaviors.stopped();
@@ -221,7 +221,7 @@ public class IntroTest {
       ctx.watch(gabbler);
       chatRoom.tell(new ChatRoom.GetSession("ol’ Gabbler", gabbler));
 
-      return Behaviors.immutable(Void.class)
+      return Behaviors.receive(Void.class)
         .onSignal(Terminated.class, (c, sig) -> Behaviors.stopped())
         .build();
     });
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/MutableIntroTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/MutableIntroTest.java
index a02fbc378b..38b499d756 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/MutableIntroTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/MutableIntroTest.java
@@ -10,6 +10,7 @@ import akka.actor.typed.Behavior;
 import akka.actor.typed.javadsl.Behaviors;
 import akka.actor.typed.javadsl.Behaviors.Receive;
 import akka.actor.typed.javadsl.ActorContext;
+import akka.actor.typed.javadsl.MutableBehavior;
 //#imports
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
@@ -82,10 +83,10 @@ public class MutableIntroTest {
     //#chatroom-behavior
 
     public static Behavior<RoomCommand> behavior() {
-      return Behaviors.mutable(ChatRoomBehavior::new);
+      return Behaviors.setup(ChatRoomBehavior::new);
     }
 
-    public static class ChatRoomBehavior extends Behaviors.MutableBehavior<RoomCommand> {
+    public static class ChatRoomBehavior extends MutableBehavior<RoomCommand> {
       final ActorContext<RoomCommand> ctx;
       final List<ActorRef<SessionCommand>> sessions = new ArrayList<>();
 
@@ -120,7 +121,7 @@ public class MutableIntroTest {
         ActorRef<RoomCommand> room,
         String screenName,
         ActorRef<SessionEvent> client) {
-      return Behaviors.immutable(ChatRoom.SessionCommand.class)
+      return Behaviors.receive(ChatRoom.SessionCommand.class)
           .onMessage(PostMessage.class, (ctx, post) -> {
             // from client, publish to others via the room
             room.tell(new PublishSessionMessage(screenName, post.message));
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/StashDocTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/StashDocTest.java
index 920fd78b47..665f9ef609 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/StashDocTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/StashDocTest.java
@@ -103,7 +103,7 @@ public class StashDocTest extends JUnitSuite {
     }
 
     private Behavior<Command> init() {
-      return Behaviors.immutable(Command.class)
+      return Behaviors.receive(Command.class)
           .onMessage(InitialState.class, (ctx, msg) -> {
             // now we are ready to handle stashed messages if any
             return buffer.unstashAll(ctx, active(msg.value));
@@ -120,7 +120,7 @@ public class StashDocTest extends JUnitSuite {
     }
 
     private Behavior<Command> active(String state) {
-      return Behaviors.immutable(Command.class)
+      return Behaviors.receive(Command.class)
           .onMessage(Get.class, (ctx, msg) -> {
             msg.replyTo.tell(state);
             return Behaviors.same();
@@ -139,7 +139,7 @@ public class StashDocTest extends JUnitSuite {
     }
 
     private Behavior<Command> saving(String state, ActorRef<Done> replyTo) {
-      return Behaviors.immutable(Command.class)
+      return Behaviors.receive(Command.class)
           .onMessageEquals(SaveSuccess.instance, ctx -> {
             replyTo.tell(Done.getInstance());
             return buffer.unstashAll(ctx, active(state));
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/TypedWatchingUntypedTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/TypedWatchingUntypedTest.java
index 10a2c1b461..1dbe57c2a2 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/TypedWatchingUntypedTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/TypedWatchingUntypedTest.java
@@ -45,7 +45,7 @@ public class TypedWatchingUntypedTest extends JUnitSuite {
         second.tell(new Typed.Ping(context.getSelf().narrow()),
           Adapter.toUntyped(context.getSelf()));
 
-        return akka.actor.typed.javadsl.Behaviors.immutable(Typed.Command.class)
+        return akka.actor.typed.javadsl.Behaviors.receive(Typed.Command.class)
           .onMessage(Typed.Pong.class, (ctx, msg) -> {
             Adapter.stop(ctx, second);
             return same();
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/UntypedWatchingTypedTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/UntypedWatchingTypedTest.java
index 0d5efe24cb..8397b850f7 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/UntypedWatchingTypedTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/coexistence/UntypedWatchingTypedTest.java
@@ -67,7 +67,7 @@ public class UntypedWatchingTypedTest extends JUnitSuite {
     public static class Pong { }
 
     public static Behavior<Command> behavior() {
-      return Behaviors.immutable(Typed.Command.class)
+      return Behaviors.receive(Typed.Command.class)
         .onMessage(Typed.Ping.class, (ctx, msg) -> {
           msg.replyTo.tell(new Pong());
           return same();
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
index e9e7183769..7cf46596eb 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
@@ -73,7 +73,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "canonicalize behaviors" in {
       val probe = TestProbe[Event]()
 
-      lazy val behavior: Behavior[Command] = Behaviors.immutable[Command] { (_, message) ⇒
+      lazy val behavior: Behavior[Command] = Behaviors.receive[Command] { (_, message) ⇒
         message match {
           case Ping ⇒
             probe.ref ! Pong
@@ -103,10 +103,10 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "correctly wire the lifecycle hook" in {
       val probe = TestProbe[Event]()
 
-      val internal = (Behaviors.immutablePartial[Command] {
+      val internal = (Behaviors.receivePartial[Command] {
         case (_, Fail) ⇒
           throw new TestException("Boom")
-      } onSignal {
+      } receiveSignal {
         case (_, signal) ⇒
           probe.ref ! GotSignal(signal)
           Behaviors.same
@@ -122,9 +122,9 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
       val probe = TestProbe[Event]()
 
       val behavior: Behavior[Command] = (
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receivePartial[Command] {
           case (_, Stop) ⇒ Behaviors.stopped
-        } onSignal {
+        } receiveSignal {
           case (_, signal) ⇒
             probe.ref ! GotSignal(signal)
             Behaviors.same
@@ -138,12 +138,12 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "restart and stop a child actor" in {
       val probe = TestProbe[Event]()
 
-      val child: Behavior[Command] = (Behaviors.immutablePartial[Command] {
+      val child: Behavior[Command] = (Behaviors.receivePartial[Command] {
         case (_, Fail) ⇒ throw new TestException("Boom")
         case (_, Ping) ⇒
           probe.ref ! Pong
           Behaviors.same
-      } onSignal {
+      } receiveSignal {
         case (_, signal) ⇒
           probe.ref ! GotChildSignal(signal)
           Behavior.stopped
@@ -156,11 +156,11 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
         ctx.watch(childRef)
         probe.ref ! ChildMade(childRef)
 
-        (Behaviors.immutablePartial[Command] {
+        (Behaviors.receivePartial[Command] {
           case (ctx, StopRef(ref)) ⇒
             ctx.stop(ref)
             Behavior.same
-        } onSignal {
+        } receiveSignal {
           case (_, signal) ⇒
             probe.ref ! GotSignal(signal)
             Behavior.stopped
@@ -185,11 +185,11 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
         val childRef = ctx.spawnAnonymous(child)
         ctx.watch(childRef)
         probe.ref ! ChildMade(childRef)
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receivePartial[Command] {
           case (ctx, StopRef(ref)) ⇒
             ctx.stop(ref)
             Behaviors.same
-        } onSignal {
+        } receiveSignal {
           case (_, signal) ⇒
             probe.ref ! GotSignal(signal)
             Behavior.stopped
@@ -205,7 +205,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
       val probe = TestProbe[Int]()
       val internal = Behaviors.setup[Command](_ ⇒ {
         var counter = 0
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receivePartial[Command] {
           case (_, Ping) ⇒
             counter += 1
             probe.ref ! counter
@@ -227,7 +227,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
       val probe = TestProbe[Int]()
       val internal = Behaviors.setup[Command](_ ⇒ {
         var counter = 0
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receivePartial[Command] {
           case (_, Ping) ⇒
             counter += 1
             probe.ref ! counter
@@ -247,25 +247,25 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "stop upon stop" in {
       val probe = TestProbe[Event]()
-      val behavior = (Behaviors.immutablePartial[Command] {
+      val behavior = (Behaviors.receivePartial[Command] {
         case (_, Ping) ⇒
           probe.ref ! Pong
           Behaviors.same
         case (_, Fail) ⇒
           throw new TestException("boom")
-      } onSignal {
+      } receiveSignal {
         case (_, PostStop) ⇒
           probe.ref ! GotSignal(PostStop)
           Behavior.same
       }).decorate
       val actorToWatch = spawn(behavior)
       val watcher: ActorRef[Command] = spawn((
-        Behaviors.immutablePartial[Any] {
+        Behaviors.receivePartial[Any] {
           case (ctx, Ping) ⇒
             ctx.watch(actorToWatch)
             probe.ref ! Pong
             Behavior.same
-        } onSignal {
+        } receiveSignal {
           case (_, signal) ⇒
             probe.ref ! GotSignal(signal)
             Behavior.same
@@ -283,7 +283,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "not stop non-child actor" in {
       val probe = TestProbe[Event]()
       val victim = spawn(Behaviors.empty[Command])
-      val actor = spawn(Behaviors.immutablePartial[Command] {
+      val actor = spawn(Behaviors.receivePartial[Command] {
         case (_, Ping) ⇒
           probe.ref ! Pong
           Behaviors.same
@@ -305,7 +305,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "watch a child actor before its termination" in {
       val probe = TestProbe[Event]()
-      val child = Behaviors.immutablePartial[Command] {
+      val child = Behaviors.receivePartial[Command] {
         case (_, Stop) ⇒
           Behaviors.stopped
       }.decorate
@@ -314,11 +314,11 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
           val childRef = ctx.spawn(child, "A")
           ctx.watch(childRef)
           probe.ref ! ChildMade(childRef)
-          Behaviors.immutablePartial[Command] {
+          Behaviors.receivePartial[Command] {
             case (_, Ping) ⇒
               probe.ref ! Pong
               Behaviors.same
-          } onSignal {
+          } receiveSignal {
             case (_, signal) ⇒
               probe.ref ! GotSignal(signal)
               Behaviors.same
@@ -332,7 +332,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "watch a child actor after its termination" in {
       val probe = TestProbe[Event]()
-      val child = Behaviors.immutablePartial[Command] {
+      val child = Behaviors.receivePartial[Command] {
         case (_, Stop) ⇒
           Behaviors.stopped
       }.decorate
@@ -340,12 +340,12 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
         Behaviors.setup[Command](ctx ⇒ {
           val childRef = ctx.spawn(child, "A")
           probe.ref ! ChildMade(childRef)
-          Behaviors.immutablePartial[Command] {
+          Behaviors.receivePartial[Command] {
             case (ctx, Watch(ref)) ⇒
               ctx.watch(ref)
               probe.ref ! Pong
               Behaviors.same
-          } onSignal {
+          } receiveSignal {
             case (_, signal) ⇒
               probe.ref ! GotSignal(signal)
               Behaviors.same
@@ -363,7 +363,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "unwatch a child actor before its termination" in {
       val probe = TestProbe[Event]()
-      val child = Behaviors.immutablePartial[Command] {
+      val child = Behaviors.receivePartial[Command] {
         case (_, Stop) ⇒
           Behaviors.stopped
       }.decorate
@@ -371,7 +371,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
         Behaviors.setup[Command](ctx ⇒ {
           val childRef = ctx.spawn(child, "A")
           probe.ref ! ChildMade(childRef)
-          Behaviors.immutablePartial[Command] {
+          Behaviors.receivePartial[Command] {
             case (ctx, Watch(ref)) ⇒
               ctx.watch(ref)
               probe.ref ! Pong
@@ -380,7 +380,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
               ctx.unwatch(ref)
               probe.ref ! Pong
               Behaviors.same
-          } onSignal {
+          } receiveSignal {
             case (_, signal) ⇒
               probe.ref ! GotSignal(signal)
               Behaviors.same
@@ -398,10 +398,10 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "terminate upon not handling Terminated" in {
       val probe = TestProbe[Event]()
-      val child = (Behaviors.immutablePartial[Command] {
+      val child = (Behaviors.receivePartial[Command] {
         case (_, Stop) ⇒
           Behaviors.stopped
-      } onSignal {
+      } receiveSignal {
         case (_, signal) ⇒
           probe.ref ! GotChildSignal(signal)
           Behavior.same
@@ -411,18 +411,18 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
           val childRef = ctx.spawn(child, "A")
           ctx.watch(childRef)
           probe.ref ! ChildMade(childRef)
-          Behaviors.immutablePartial[Command] {
+          Behaviors.receivePartial[Command] {
             case (_, Inert) ⇒
               probe.ref ! InertEvent
-              Behaviors.immutable[Command] {
+              Behaviors.receive[Command] {
                 case (_, _) ⇒ Behaviors.unhandled
-              } onSignal {
+              } receiveSignal {
                 case (_, Terminated(_)) ⇒ Behaviors.unhandled
                 case (_, signal) ⇒
                   probe.ref ! GotSignal(signal)
                   Behaviors.same
               }
-          } onSignal {
+          } receiveSignal {
             case (_, signal) ⇒
               probe.ref ! GotSignal(signal)
               Behaviors.same
@@ -441,7 +441,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "return the right context info" in {
       type Info = (ActorSystem[Nothing], ActorRef[String])
       val probe = TestProbe[Info]
-      val actor = spawn(Behaviors.immutablePartial[String] {
+      val actor = spawn(Behaviors.receivePartial[String] {
         case (ctx, "info") ⇒
           probe.ref ! (ctx.system → ctx.self)
           Behaviors.same
@@ -453,7 +453,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
     "return right info about children" in {
       type Children = Seq[ActorRef[Nothing]]
       val probe = TestProbe[Children]()
-      val actor = spawn(Behaviors.immutablePartial[String] {
+      val actor = spawn(Behaviors.receivePartial[String] {
         case (ctx, "create") ⇒
           ctx.spawn(Behaviors.empty, "B")
           probe.ref ! ctx.child("B").toSeq
@@ -477,7 +477,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "set small receive timeout" in {
       val probe = TestProbe[Event]()
-      val actor = spawn(Behaviors.immutablePartial[Command] {
+      val actor = spawn(Behaviors.receivePartial[Command] {
         case (_, ReceiveTimeout) ⇒
           probe.ref ! GotReceiveTimeout
           Behaviors.same
@@ -493,7 +493,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "set large receive timeout" in {
       val probe = TestProbe[String]()
-      val actor = spawn(Behaviors.immutablePartial[String] {
+      val actor = spawn(Behaviors.receivePartial[String] {
         case (ctx, "schedule") ⇒
           ctx.schedule(1.second, probe.ref, "scheduled")
           Behaviors.same
@@ -518,7 +518,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
 
     "schedule a message" in {
       val probe = TestProbe[Event]()
-      val actor = spawn(Behaviors.immutablePartial[Command] {
+      val actor = spawn(Behaviors.receivePartial[Command] {
         case (ctx, Ping) ⇒
           ctx.schedule(1.nano, probe.ref, Pong)
           Behaviors.same
@@ -531,7 +531,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
       type Envelope = (ActorRef[String], String)
       val messages = TestProbe[Envelope]()
       val probe = TestProbe[ActorRef[String]]()
-      val actor = spawn(Behaviors.immutablePartial[String] {
+      val actor = spawn(Behaviors.receivePartial[String] {
         case (ctx, "message") ⇒
           messages.ref.tell((ctx.self, "received message"))
           Behaviors.same
@@ -560,7 +560,7 @@ abstract class ActorContextSpec extends ActorTestKit with TypedAkkaSpecWithShutd
         Behaviors.setup[Command](ctx ⇒ {
           val child = ctx.spawnAnonymous(Behaviors.empty[Command])
           probe.ref ! ChildMade(child)
-          Behaviors.immutablePartial[Command] {
+          Behaviors.receivePartial[Command] {
             case (ctx, StopRef(ref)) ⇒
               ctx.stop(ref)
               probe.ref ! Pong
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
index 8d41c2cac3..eb3e6f27ad 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
@@ -35,7 +35,7 @@ class AskSpec extends ActorTestKit
   implicit def executor: ExecutionContext =
     system.executionContext
 
-  val behavior: Behavior[Msg] = immutable[Msg] {
+  val behavior: Behavior[Msg] = receive[Msg] {
     case (_, foo: Foo) ⇒
       foo.replyTo ! "foo"
       Behaviors.same
@@ -119,7 +119,7 @@ class AskSpec extends ActorTestKit
 
       val probe = TestProbe[AnyRef]("probe")
       val behv =
-        Behaviors.immutable[String] {
+        Behaviors.receive[String] {
           case (ctx, "start-ask") ⇒
             ctx.ask[Question, Long](probe.ref)(Question(_)) {
               case Success(42L) ⇒
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
index 54488e7d66..3e4f87368e 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
@@ -5,6 +5,7 @@
 package akka.actor.typed
 
 import akka.actor.typed.scaladsl.{ Behaviors ⇒ SBehaviors }
+import akka.actor.typed.scaladsl.{ MutableBehavior ⇒ SMutableBehavior }
 import akka.actor.typed.javadsl.{ ActorContext ⇒ JActorContext, Behaviors ⇒ JBehaviors }
 import akka.japi.function.{ Function ⇒ F1e, Function2 ⇒ F2, Procedure2 ⇒ P2 }
 import akka.japi.pf.{ FI, PFBuilder }
@@ -138,7 +139,7 @@ object BehaviorSpec {
   }
 
   def mkFull(monitor: ActorRef[Event], state: State = StateA): Behavior[Command] = {
-    SBehaviors.immutable[Command] {
+    SBehaviors.receive[Command] {
       case (ctx, GetSelf) ⇒
         monitor ! Self(ctx.self)
         SBehaviors.same
@@ -159,7 +160,7 @@ object BehaviorSpec {
         SBehaviors.same
       case (_, Stop) ⇒ SBehaviors.stopped
       case (_, _)    ⇒ SBehaviors.unhandled
-    } onSignal {
+    } receiveSignal {
       case (_, signal) ⇒
         monitor ! GotSignal(signal)
         SBehaviors.same
@@ -343,10 +344,10 @@ class FullBehaviorSpec extends TypedAkkaSpec with Messages with BecomeWithLifecy
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = mkFull(monitor) → null
 }
 
-class ImmutableBehaviorSpec extends Messages with BecomeWithLifecycle with Stoppable {
+class ReceiveBehaviorSpec extends Messages with BecomeWithLifecycle with Stoppable {
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor, StateA) → null
   private def behv(monitor: ActorRef[Event], state: State): Behavior[Command] = {
-    SBehaviors.immutable[Command] {
+    SBehaviors.receive[Command] {
       case (ctx, GetSelf) ⇒
         monitor ! Self(ctx.self)
         SBehaviors.same
@@ -367,7 +368,7 @@ class ImmutableBehaviorSpec extends Messages with BecomeWithLifecycle with Stopp
         SBehaviors.same
       case (_, Stop)       ⇒ SBehaviors.stopped
       case (_, _: AuxPing) ⇒ SBehaviors.unhandled
-    } onSignal {
+    } receiveSignal {
       case (_, signal) ⇒
         monitor ! GotSignal(signal)
         SBehaviors.same
@@ -380,7 +381,7 @@ class ImmutableWithSignalScalaBehaviorSpec extends TypedAkkaSpec with Messages w
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor) → null
 
   def behv(monitor: ActorRef[Event], state: State = StateA): Behavior[Command] =
-    SBehaviors.immutable[Command] {
+    SBehaviors.receive[Command] {
       (ctx, msg) ⇒
         msg match {
           case GetSelf ⇒
@@ -404,7 +405,7 @@ class ImmutableWithSignalScalaBehaviorSpec extends TypedAkkaSpec with Messages w
           case Stop       ⇒ SBehaviors.stopped
           case _: AuxPing ⇒ SBehaviors.unhandled
         }
-    } onSignal {
+    } receiveSignal {
       case (_, sig) ⇒
         monitor ! GotSignal(sig)
         SBehaviors.same
@@ -416,7 +417,7 @@ class ImmutableScalaBehaviorSpec extends Messages with Become with Stoppable {
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor, StateA) → null
 
   def behv(monitor: ActorRef[Event], state: State): Behavior[Command] =
-    SBehaviors.immutable[Command] { (ctx, msg) ⇒
+    SBehaviors.receive[Command] { (ctx, msg) ⇒
       msg match {
         case GetSelf ⇒
           monitor ! Self(ctx.self)
@@ -447,8 +448,8 @@ class MutableScalaBehaviorSpec extends Messages with Become with Stoppable {
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor) → null
 
   def behv(monitor: ActorRef[Event]): Behavior[Command] =
-    SBehaviors.mutable[Command] { ctx ⇒
-      new SBehaviors.MutableBehavior[Command] {
+    SBehaviors.setup[Command] { ctx ⇒
+      new SMutableBehavior[Command] {
         private var state: State = StateA
 
         override def onMessage(msg: Command): Behavior[Command] = {
@@ -519,7 +520,7 @@ class RestarterScalaBehaviorSpec extends ImmutableWithSignalScalaBehaviorSpec wi
 class ImmutableWithSignalJavaBehaviorSpec extends Messages with BecomeWithLifecycle with Stoppable {
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor) → null
   def behv(monitor: ActorRef[Event], state: State = StateA): Behavior[Command] =
-    JBehaviors.immutable(
+    JBehaviors.receive(
       fc((ctx, msg) ⇒ msg match {
         case GetSelf ⇒
           monitor ! Self(ctx.getSelf)
@@ -551,7 +552,7 @@ class ImmutableWithSignalJavaBehaviorSpec extends Messages with BecomeWithLifecy
 class ImmutableJavaBehaviorSpec extends Messages with Become with Stoppable {
   override def behavior(monitor: ActorRef[Event]): (Behavior[Command], Aux) = behv(monitor, StateA) → null
   def behv(monitor: ActorRef[Event], state: State): Behavior[Command] =
-    JBehaviors.immutable {
+    JBehaviors.receive {
       fc((ctx, msg) ⇒
         msg match {
           case GetSelf ⇒
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/DeferredSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/DeferredSpec.scala
index 55a6423c9b..8b76b8f63c 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/DeferredSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/DeferredSpec.scala
@@ -19,7 +19,7 @@ object DeferredSpec {
   case object Started extends Event
 
   def target(monitor: ActorRef[Event]): Behavior[Command] =
-    Behaviors.immutable((_, cmd) ⇒ cmd match {
+    Behaviors.receive((_, cmd) ⇒ cmd match {
       case Ping ⇒
         monitor ! Pong
         Behaviors.same
@@ -52,7 +52,7 @@ class DeferredSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           throw new RuntimeException("simulated exc from factory") with NoStackTrace
         })
         ctx.watch(child)
-        Behaviors.immutable[Command]((_, _) ⇒ Behaviors.same).onSignal {
+        Behaviors.receive[Command]((_, _) ⇒ Behaviors.same).receiveSignal {
           case (_, Terminated(`child`)) ⇒
             probe.ref ! Pong
             Behaviors.stopped
@@ -68,7 +68,7 @@ class DeferredSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       val behv = Behaviors.setup[Command] { ctx ⇒
         val child = ctx.spawnAnonymous(Behaviors.setup[Command](_ ⇒ Behaviors.stopped))
         ctx.watch(child)
-        Behaviors.immutable[Command]((_, _) ⇒ Behaviors.same).onSignal {
+        Behaviors.receive[Command]((_, _) ⇒ Behaviors.same).receiveSignal {
           case (_, Terminated(`child`)) ⇒
             probe.ref ! Pong
             Behaviors.stopped
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/SupervisionSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/SupervisionSpec.scala
index ab349e1ed6..c53ea36df2 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/SupervisionSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/SupervisionSpec.scala
@@ -8,7 +8,7 @@ import java.io.IOException
 import java.util.concurrent.atomic.AtomicInteger
 
 import akka.actor.ActorInitializationException
-import akka.actor.typed.scaladsl.Behaviors
+import akka.actor.typed.scaladsl.{ Behaviors, MutableBehavior }
 import akka.actor.typed.scaladsl.Behaviors._
 import akka.testkit.EventFilter
 import akka.testkit.typed.scaladsl._
@@ -40,7 +40,7 @@ object SupervisionSpec {
   class Exc3(msg: String = "exc-3") extends RuntimeException(msg) with NoStackTrace
 
   def targetBehavior(monitor: ActorRef[Event], state: State = State(0, Map.empty)): Behavior[Command] =
-    immutable[Command] { (ctx, cmd) ⇒
+    receive[Command] { (ctx, cmd) ⇒
       cmd match {
         case Ping ⇒
           monitor ! Pong
@@ -57,7 +57,7 @@ object SupervisionSpec {
         case Throw(e) ⇒
           throw e
       }
-    } onSignal {
+    } receiveSignal {
       case (_, sig) ⇒
         monitor ! GotSignal(sig)
         Behaviors.same
@@ -623,7 +623,7 @@ class SupervisionSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
 
     "fail when exception from MutableBehavior constructor" in new FailingConstructorTestSetup(failCount = 1) {
       val probe = TestProbe[Event]("evt")
-      val behv = supervise(mutable[Command](_ ⇒ new FailingConstructor(probe.ref)))
+      val behv = supervise(setup[Command](_ ⇒ new FailingConstructor(probe.ref)))
         .onFailure[Exception](SupervisorStrategy.restart)
 
       EventFilter[ActorInitializationException](occurrences = 1).intercept {
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/TimerSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/TimerSpec.scala
index a33d687b9d..dfae427540 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/TimerSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/TimerSpec.scala
@@ -45,7 +45,7 @@ class TimerSpec extends ActorTestKit with WordSpecLike with TypedAkkaSpecWithShu
       target(monitor, timer, nextCount)
     }
 
-    Behaviors.immutable[Command] { (ctx, cmd) ⇒
+    Behaviors.receive[Command] { (ctx, cmd) ⇒
       cmd match {
         case Tick(n) ⇒
           monitor ! Tock(n)
@@ -67,7 +67,7 @@ class TimerSpec extends ActorTestKit with WordSpecLike with TypedAkkaSpecWithShu
           latch.await(10, TimeUnit.SECONDS)
           throw e
       }
-    } onSignal {
+    } receiveSignal {
       case (ctx, PreRestart) ⇒
         monitor ! GotPreRestart(timer.isTimerActive("T"))
         Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/WatchSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/WatchSpec.scala
index 0f3a48082a..615d8bc24f 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/WatchSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/WatchSpec.scala
@@ -6,7 +6,7 @@ package akka.actor.typed
 
 import akka.Done
 import akka.actor.typed.scaladsl.Behaviors
-import akka.actor.typed.scaladsl.Behaviors.MutableBehavior
+import akka.actor.typed.scaladsl.MutableBehavior
 import akka.actor.typed.scaladsl.adapter._
 import akka.testkit.EventFilter
 import akka.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
@@ -21,7 +21,7 @@ object WatchSpec {
   case object Stop
 
   val terminatorBehavior =
-    Behaviors.immutable[Stop.type] {
+    Behaviors.receive[Stop.type] {
       case (_, Stop) ⇒ Behaviors.stopped
     }
 
@@ -54,12 +54,12 @@ class WatchSpec extends ActorTestKit
 
     val watcher = systemActor(
       Behaviors.supervise(
-        Behaviors.immutable[StartWatching] {
+        Behaviors.receive[StartWatching] {
           case (ctx, StartWatching(watchee)) ⇒
             ctx.watch(watchee)
             watchProbe.ref ! Done
             Behaviors.same
-        }.onSignal {
+        }.receiveSignal {
           case (_, t: Terminated) ⇒
             receivedTerminationSignal.success(t)
             Behaviors.stopped
@@ -83,15 +83,15 @@ class WatchSpec extends ActorTestKit
       val probe = TestProbe[Any]()
       val ex = new TestException("boom")
       val parent = spawn(Behaviors.setup[Any] { ctx ⇒
-        val child = ctx.spawn(Behaviors.immutable[Any]((ctx, msg) ⇒
+        val child = ctx.spawn(Behaviors.receive[Any]((ctx, msg) ⇒
           throw ex
         ), "child")
         ctx.watch(child)
 
-        Behaviors.immutable[Any] { (ctx, msg) ⇒
+        Behaviors.receive[Any] { (ctx, msg) ⇒
           child ! msg
           Behaviors.same
-        }.onSignal {
+        }.receiveSignal {
           case (_, t: Terminated) ⇒
             probe.ref ! Failed(t)
             Behaviors.same
@@ -110,12 +110,12 @@ class WatchSpec extends ActorTestKit
       val ex = new TestException("boom")
       val grossoBosso = spawn(Behaviors.setup[Any] { ctx ⇒
         val middleManagement = ctx.spawn(Behaviors.setup[Any] { ctx ⇒
-          val sixPackJoe = ctx.spawn(Behaviors.immutable[Any]((ctx, msg) ⇒
+          val sixPackJoe = ctx.spawn(Behaviors.receive[Any]((ctx, msg) ⇒
             throw ex
           ), "joe")
           ctx.watch(sixPackJoe)
 
-          Behaviors.immutable[Any] { (ctx, msg) ⇒
+          Behaviors.receive[Any] { (ctx, msg) ⇒
             sixPackJoe ! msg
             Behaviors.same
           } // no handling of terminated, even though we watched!!!
@@ -123,10 +123,10 @@ class WatchSpec extends ActorTestKit
 
         ctx.watch(middleManagement)
 
-        Behaviors.immutable[Any] { (ctx, msg) ⇒
+        Behaviors.receive[Any] { (ctx, msg) ⇒
           middleManagement ! msg
           Behaviors.same
-        }.onSignal {
+        }.receiveSignal {
           case (_, t: Terminated) ⇒
             probe.ref ! Failed(t)
             Behaviors.stopped
@@ -161,7 +161,7 @@ class WatchSpec extends ActorTestKit
 
       val watcher = systemActor(
         Behaviors.supervise(
-          Behaviors.immutable[Message] {
+          Behaviors.receive[Message] {
             case (ctx, StartWatchingWith(watchee, msg)) ⇒
               ctx.watchWith(watchee, msg)
               watchProbe.ref ! Done
@@ -197,7 +197,7 @@ class WatchSpec extends ActorTestKit
 
       val watcher = systemActor(
         Behaviors.supervise(
-          Behaviors.immutable[Message] {
+          Behaviors.receive[Message] {
             case (ctx, StartWatching(watchee)) ⇒
               ctx.watch(watchee)
               Behaviors.same
@@ -227,7 +227,7 @@ class WatchSpec extends ActorTestKit
 
       val watcher = systemActor(
         Behaviors.supervise(
-          Behaviors.immutable[Message] {
+          Behaviors.receive[Message] {
             case (ctx, StartWatchingWith(watchee, msg)) ⇒
               ctx.unwatch(watchee)
               ctx.watchWith(watchee, msg)
@@ -253,7 +253,7 @@ class WatchSpec extends ActorTestKit
 
       val watcher = systemActor(
         Behaviors.supervise(
-          Behaviors.immutable[Message] {
+          Behaviors.receive[Message] {
             case (ctx, StartWatchingWith(watchee, msg)) ⇒
               ctx.watchWith(watchee, msg)
               Behaviors.same
@@ -262,7 +262,7 @@ class WatchSpec extends ActorTestKit
               Behaviors.same
             case (_, msg) ⇒
               Behaviors.stopped
-          }.onSignal {
+          }.receiveSignal {
             case (_, PostStop) ⇒
               Behaviors.stopped
           }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/ActorSystemSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/ActorSystemSpec.scala
index d2594243a5..2a8e5a77a4 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/ActorSystemSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/ActorSystemSpec.scala
@@ -41,7 +41,7 @@ class ActorSystemSpec extends WordSpec with Matchers with BeforeAndAfterAll
     "start the guardian actor and terminate when it terminates" in {
       val t = withSystem(
         "a",
-        Behaviors.immutable[Probe] { case (_, p) ⇒ p.replyTo ! p.msg; Behaviors.stopped }, doTerminate = false) { sys ⇒
+        Behaviors.receive[Probe] { case (_, p) ⇒ p.replyTo ! p.msg; Behaviors.stopped }, doTerminate = false) { sys ⇒
           val inbox = TestInbox[String]("a")
           sys ! Probe("hello", inbox.ref)
           eventually {
@@ -57,7 +57,7 @@ class ActorSystemSpec extends WordSpec with Matchers with BeforeAndAfterAll
     // see issue #24172
     "shutdown if guardian shuts down immediately" in {
       val stoppable =
-        Behaviors.immutable[Done] {
+        Behaviors.receive[Done] {
           case (ctx, Done) ⇒ Behaviors.stopped
         }
       withSystem("shutdown", stoppable, doTerminate = false) { sys: ActorSystem[Done] ⇒
@@ -69,9 +69,9 @@ class ActorSystemSpec extends WordSpec with Matchers with BeforeAndAfterAll
     "terminate the guardian actor" in {
       val inbox = TestInbox[String]("terminate")
       val sys = system(
-        Behaviors.immutable[Probe] {
+        Behaviors.receive[Probe] {
           case (_, _) ⇒ Behaviors.unhandled
-        } onSignal {
+        } receiveSignal {
           case (_, PostStop) ⇒
             inbox.ref ! "done"
             Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/receptionist/LocalReceptionistSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/receptionist/LocalReceptionistSpec.scala
index 9c29fec995..8ed04bd7e0 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/receptionist/LocalReceptionistSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/internal/receptionist/LocalReceptionistSpec.scala
@@ -26,7 +26,7 @@ class LocalReceptionistSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
   val behaviorB = Behaviors.empty[ServiceB]
 
   case object Stop extends ServiceA with ServiceB
-  val stoppableBehavior = Behaviors.immutable[Any] { (_, msg) ⇒
+  val stoppableBehavior = Behaviors.receive[Any] { (_, msg) ⇒
     msg match {
       case Stop ⇒ Behavior.stopped
       case _    ⇒ Behavior.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/receptionist/ReceptionistApiSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/receptionist/ReceptionistApiSpec.scala
index d194ba73d8..98d0c4a21f 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/receptionist/ReceptionistApiSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/receptionist/ReceptionistApiSpec.scala
@@ -67,7 +67,7 @@ object ReceptionistApiSpec {
       // to cover as much of the API as possible
       ctx.system.receptionist ! Receptionist.Register(key, ctx.self.narrow, ctx.self.narrow)
 
-      Behaviors.immutable { (ctx, msg) ⇒
+      Behaviors.receive { (ctx, msg) ⇒
         msg match {
           case key.Listing(services) ⇒
             services.foreach(_ ! "woho")
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
index 8720e056c8..5cf800fe81 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
@@ -42,7 +42,7 @@ class ActorContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       case class Ping(sender: ActorRef[Pong])
       case class Pong(selfName: String, threadName: String)
 
-      val pingPong = spawn(Behaviors.immutable[Ping] { (ctx, msg) ⇒
+      val pingPong = spawn(Behaviors.receive[Ping] { (ctx, msg) ⇒
         msg.sender ! Pong(ctx.self.path.name, Thread.currentThread().getName)
         Behaviors.same
       }, "ping-pong", Props.empty.withDispatcherFromConfig("ping-pong-dispatcher"))
@@ -58,7 +58,7 @@ class ActorContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           case Failure(ex)   ⇒ throw ex
         }
 
-        Behaviors.immutable {
+        Behaviors.receive {
           case (ctx, pong: Pong) ⇒
             probe.ref ! pong
             Behaviors.same
@@ -80,7 +80,7 @@ class ActorContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       case class Ping(respondTo: ActorRef[Pong.type]) extends Protocol
       case object Pong extends Protocol
 
-      val pingPong = spawn(Behaviors.immutable[Protocol]((_, msg) ⇒
+      val pingPong = spawn(Behaviors.receive[Protocol]((_, msg) ⇒
         msg match {
           case Ping(respondTo) ⇒
             respondTo ! Pong
@@ -94,11 +94,11 @@ class ActorContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           case Failure(x)   ⇒ x
         }
 
-        Behaviors.immutable[AnyRef] {
+        Behaviors.receive[AnyRef] {
           case (_, msg) ⇒
             probe.ref ! msg
             Behaviors.same
-        }.onSignal {
+        }.receiveSignal {
 
           case (_, PostStop) ⇒
             probe.ref ! "stopped"
@@ -123,7 +123,7 @@ class ActorContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           case Failure(x) ⇒ x
         }(20.millis, implicitly[ClassTag[String]])
 
-        Behaviors.immutable {
+        Behaviors.receive {
           case (_, msg) ⇒
             probe.ref ! msg
             Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorLoggingSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorLoggingSpec.scala
index 5b3667369a..e3fe56c623 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorLoggingSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorLoggingSpec.scala
@@ -34,7 +34,7 @@ class ActorLoggingSpec extends ActorTestKit with TypedAkkaSpec {
         spawn(Behaviors.setup[String] { ctx ⇒
           ctx.log.info("Started")
 
-          Behaviors.immutable { (ctx, msg) ⇒
+          Behaviors.receive { (ctx, msg) ⇒
             ctx.log.info("got message {}", msg)
             Behaviors.same
           }
@@ -204,7 +204,7 @@ class ActorLoggingSpec extends ActorTestKit with TypedAkkaSpec {
         },
         Behaviors.setup { ctx ⇒
           ctx.log.info("Starting")
-          Behaviors.immutable { (ctx, msg) ⇒
+          Behaviors.receive { (ctx, msg) ⇒
             ctx.log.info("Got message!")
             Behaviors.same
           }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/GracefulStopSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/GracefulStopSpec.scala
index 5501b7d0a3..0bccc496ed 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/GracefulStopSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/GracefulStopSpec.scala
@@ -18,20 +18,20 @@ final class GracefulStopSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
 
       val behavior =
         Behaviors.setup[akka.NotUsed] { context ⇒
-          val c1 = context.spawn[NotUsed](Behaviors.onSignal {
+          val c1 = context.spawn[NotUsed](Behaviors.receiveSignal {
             case (_, PostStop) ⇒
               probe.ref ! "child-done"
               Behaviors.stopped
           }, "child1")
 
-          val c2 = context.spawn[NotUsed](Behaviors.onSignal {
+          val c2 = context.spawn[NotUsed](Behaviors.receiveSignal {
             case (_, PostStop) ⇒
               probe.ref ! "child-done"
               Behaviors.stopped
           }, "child2")
 
           Behaviors.stopped {
-            Behaviors.onSignal {
+            Behaviors.receiveSignal {
               case (ctx, PostStop) ⇒
                 // cleanup function body
                 probe.ref ! "parent-done"
@@ -53,7 +53,7 @@ final class GracefulStopSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
         Behaviors.setup[akka.NotUsed] { context ⇒
           // do not spawn any children
           Behaviors.stopped {
-            Behaviors.onSignal {
+            Behaviors.receiveSignal {
               case (ctx, PostStop) ⇒
                 // cleanup function body
                 probe.ref ! Done
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
index 0362c4bb5f..76861a4ae0 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
@@ -49,7 +49,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
 
       case class AnotherPong(selfName: String, threadName: String)
 
-      val pingPong = spawn(Behaviors.immutable[Ping] { (ctx, msg) ⇒
+      val pingPong = spawn(Behaviors.receive[Ping] { (ctx, msg) ⇒
         msg.sender ! Pong(ctx.self.path.name, Thread.currentThread().getName)
         Behaviors.same
       }, "ping-pong", Props.empty.withDispatcherFromConfig("ping-pong-dispatcher"))
@@ -67,7 +67,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           AnotherPong(ctx.self.path.name, Thread.currentThread().getName))
         pingPong ! Ping(replyTo2)
 
-        Behaviors.immutable {
+        Behaviors.receive {
           case (_, anotherPong: AnotherPong) ⇒
             probe.ref ! anotherPong
             Behaviors.same
@@ -96,7 +96,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
 
       case class Wrapped(qualifier: String, response: Response)
 
-      val pingPong = spawn(Behaviors.immutable[Ping] { (_, msg) ⇒
+      val pingPong = spawn(Behaviors.receive[Ping] { (_, msg) ⇒
         msg match {
           case Ping1(sender) ⇒
             sender ! Pong1("hello-1")
@@ -117,7 +117,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
         pingPong ! Ping1(replyTo1)
         pingPong ! Ping2(replyTo2)
 
-        Behaviors.immutable {
+        Behaviors.receive {
           case (_, wrapped) ⇒
             probe.ref ! wrapped
             Behaviors.same
@@ -140,7 +140,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
 
       case class Wrapped(qualifier: String, response: Response)
 
-      val pingPong = spawn(Behaviors.immutable[Ping] { (_, msg) ⇒
+      val pingPong = spawn(Behaviors.receive[Ping] { (_, msg) ⇒
         msg match {
           case Ping1(sender) ⇒
             sender ! Pong1("hello-1")
@@ -163,7 +163,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
         pingPong ! Ping2(replyTo1.asInstanceOf[ActorRef[Pong2]])
         pingPong ! Ping1(replyTo1)
 
-        Behaviors.immutable {
+        Behaviors.receive {
           case (_, wrapped) ⇒
             probe.ref ! wrapped
             Behaviors.same
@@ -184,7 +184,7 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       case class Pong(greeting: String)
       case class Wrapped(count: Int, response: Pong)
 
-      val pingPong = spawn(Behaviors.immutable[Ping] { (_, ping) ⇒
+      val pingPong = spawn(Behaviors.receive[Ping] { (_, ping) ⇒
         ping.sender ! Pong("hello")
         Behaviors.same
       })
@@ -203,11 +203,11 @@ class MessageAdapterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           pingPong ! Ping(replyTo)
         }
 
-        Behaviors.immutable[Wrapped] {
+        Behaviors.receive[Wrapped] {
           case (_, wrapped) ⇒
             probe.ref ! wrapped
             Behaviors.same
-        }.onSignal {
+        }.receiveSignal {
           case (_, PostStop) ⇒
             probe.ref ! "stopped"
             Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/OnSignalSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/OnSignalSpec.scala
index ae5c44e699..9c7e465e24 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/OnSignalSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/OnSignalSpec.scala
@@ -17,7 +17,7 @@ final class OnSignalSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
         Behaviors.setup[Nothing] { context ⇒
           val stoppedChild = context.spawn(Behaviors.stopped, "stopped-child")
           context.watch(stoppedChild)
-          Behaviors.onSignal[Nothing] {
+          Behaviors.receiveSignal[Nothing] {
             case (_, Terminated(`stoppedChild`)) ⇒
               probe.ref ! Done
               Behaviors.stopped
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ImmutablePartialSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ReceivePartialSpec.scala
similarity index 53%
rename from akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ImmutablePartialSpec.scala
rename to akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ReceivePartialSpec.scala
index 1097be58c8..cdc7e90d5c 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ImmutablePartialSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ReceivePartialSpec.scala
@@ -7,14 +7,31 @@ package scaladsl
 
 import akka.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
 
-class ImmutablePartialSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
+class ReceivePartialSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
 
   "An immutable partial" must {
 
-    "correctly install the message handler" in {
+    "correctly install the receiveMessage handler" in {
       val probe = TestProbe[Command]("probe")
       val behavior =
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receiveMessagePartial[Command] {
+          case Command2 ⇒
+            probe.ref ! Command2
+            Behaviors.same
+        }
+      val actor = spawn(behavior)
+
+      actor ! Command1
+      probe.expectNoMessage()
+
+      actor ! Command2
+      probe.expectMessage(Command2)
+    }
+
+    "correctly install the receive handler" in {
+      val probe = TestProbe[Command]("probe")
+      val behavior =
+        Behaviors.receivePartial[Command] {
           case (_, Command2) ⇒
             probe.ref ! Command2
             Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashBufferSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashBufferSpec.scala
index abdc3d0dbc..da42d76416 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashBufferSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashBufferSpec.scala
@@ -85,7 +85,7 @@ class StashBufferSpec extends WordSpec with Matchers {
 
       val valueInbox = TestInbox[String]()
       def behavior(state: String): Behavior[String] =
-        Behaviors.immutable[String] { (_, msg) ⇒
+        Behaviors.receive[String] { (_, msg) ⇒
           if (msg == "get") {
             valueInbox.ref ! state
             Behaviors.same
@@ -108,7 +108,7 @@ class StashBufferSpec extends WordSpec with Matchers {
 
       val valueInbox = TestInbox[String]()
       def behavior(state: String): Behavior[String] =
-        Behaviors.immutable[String] { (_, msg) ⇒
+        Behaviors.receive[String] { (_, msg) ⇒
           if (msg == "get") {
             valueInbox.ref ! state
             Behaviors.same
@@ -131,7 +131,7 @@ class StashBufferSpec extends WordSpec with Matchers {
 
       val valueInbox = TestInbox[String]()
       def behavior(state: String): Behavior[String] =
-        Behaviors.immutable[String] { (_, msg) ⇒
+        Behaviors.receive[String] { (_, msg) ⇒
           if (msg == "get") {
             valueInbox.ref ! state
             Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
index 626567a9c6..1f0b0b054e 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
@@ -23,7 +23,7 @@ object StashSpec {
       val buffer = StashBuffer[Command](capacity = 10)
 
       def active(processed: Vector[String]): Behavior[Command] =
-        Behaviors.immutable { (ctx, cmd) ⇒
+        Behaviors.receive { (ctx, cmd) ⇒
           cmd match {
             case msg: Msg ⇒
               active(processed :+ msg.s)
@@ -45,7 +45,7 @@ object StashSpec {
         }
 
       def stashing(processed: Vector[String]): Behavior[Command] =
-        Behaviors.immutable { (ctx, cmd) ⇒
+        Behaviors.receive { (ctx, cmd) ⇒
           cmd match {
             case msg: Msg ⇒
               buffer.stash(msg)
@@ -76,7 +76,7 @@ object StashSpec {
         }
 
       def unstashing(processed: Vector[String]): Behavior[Command] =
-        Behaviors.immutable { (ctx, cmd) ⇒
+        Behaviors.receive { (ctx, cmd) ⇒
           cmd match {
             case Unstashed(msg: Msg) ⇒
               ctx.log.debug(s"unstashed $msg")
@@ -118,7 +118,7 @@ object StashSpec {
       active(Vector.empty)
     }
 
-  class MutableStash(ctx: ActorContext[Command]) extends Behaviors.MutableBehavior[Command] {
+  class MutableStash(ctx: ActorContext[Command]) extends MutableBehavior[Command] {
 
     private val buffer = StashBuffer.apply[Command](capacity = 10)
     private var stashing = false
@@ -183,7 +183,7 @@ class ImmutableStashSpec extends StashSpec {
 class MutableStashSpec extends StashSpec {
   import StashSpec._
   def testQualifier: String = "mutable behavior"
-  def behaviorUnderTest: Behavior[Command] = Behaviors.mutable(ctx ⇒ new MutableStash(ctx))
+  def behaviorUnderTest: Behavior[Command] = Behaviors.setup(ctx ⇒ new MutableStash(ctx))
 }
 
 abstract class StashSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/adapter/AdapterSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/adapter/AdapterSpec.scala
index 325f11299c..e55544d2b2 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/adapter/AdapterSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/adapter/AdapterSpec.scala
@@ -34,7 +34,7 @@ object AdapterSpec {
   }
 
   def typed1(ref: untyped.ActorRef, probe: ActorRef[String]): Behavior[String] =
-    Behaviors.immutable[String] {
+    Behaviors.receive[String] {
       (ctx, msg) ⇒
         msg match {
           case "send" ⇒
@@ -63,7 +63,7 @@ object AdapterSpec {
             ctx.stop(child)
             Behaviors.same
         }
-    } onSignal {
+    } receiveSignal {
       case (ctx, Terminated(ref)) ⇒
         probe ! "terminated"
         Behaviors.same
@@ -132,7 +132,7 @@ object AdapterSpec {
   }
 
   def typed2: Behavior[Typed2Msg] =
-    Behaviors.immutable { (ctx, msg) ⇒
+    Behaviors.receive { (ctx, msg) ⇒
       msg match {
         case Ping(replyTo) ⇒
           replyTo ! "pong"
@@ -172,7 +172,7 @@ class AdapterSpec extends AkkaSpec {
       for { _ ← 0 to 10 } {
         var system: akka.actor.typed.ActorSystem[Done] = null
         try {
-          system = ActorSystem.create(Behaviors.immutable[Done] { (ctx, msg) ⇒
+          system = ActorSystem.create(Behaviors.receive[Done] { (ctx, msg) ⇒
             ctx.self ! Done
             msg match {
               case Done ⇒ Behaviors.stopped
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/FaultToleranceDocSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/FaultToleranceDocSpec.scala
index 1a386c8576..78900d7d45 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/FaultToleranceDocSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/FaultToleranceDocSpec.scala
@@ -27,7 +27,7 @@ class FaultToleranceDocSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
       sealed trait Message
       case class Fail(text: String) extends Message
 
-      val worker = Behaviors.immutable[Message] { (ctx, msg) ⇒
+      val worker = Behaviors.receive[Message] { (ctx, msg) ⇒
         msg match {
           case Fail(text) ⇒ throw new RuntimeException(text)
         }
@@ -41,7 +41,7 @@ class FaultToleranceDocSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
         // here we don't handle Terminated at all which means that
         // when the child fails or stops gracefully this actor will
         // fail with a DeathWatchException
-        Behaviors.immutable[Message] { (ctx, msg) ⇒
+        Behaviors.receive[Message] { (ctx, msg) ⇒
           child ! msg
           Behaviors.same
         }
@@ -55,7 +55,7 @@ class FaultToleranceDocSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
         // here we don't handle Terminated at all which means that
         // when middle management fails with a DeathWatchException
         // this actor will also fail
-        Behaviors.immutable[Message] { (ctx, msg) ⇒
+        Behaviors.receive[Message] { (ctx, msg) ⇒
           middleManagment ! msg
           Behaviors.same
         }
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/GracefulStopDocSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/GracefulStopDocSpec.scala
index b1ee1c91b4..c313fceec3 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/GracefulStopDocSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/GracefulStopDocSpec.scala
@@ -27,7 +27,7 @@ object GracefulStopDocSpec {
     // Predefined cleanup operation
     def cleanup(log: Logger): Unit = log.info("Cleaning up!")
 
-    val mcpa = Behaviors.immutable[JobControlLanguage] { (ctx, msg) ⇒
+    val mcpa = Behaviors.receive[JobControlLanguage] { (ctx, msg) ⇒
       msg match {
         case SpawnJob(jobName) ⇒
           ctx.log.info("Spawning job {}!", jobName)
@@ -38,14 +38,14 @@ object GracefulStopDocSpec {
           // perform graceful stop, executing cleanup before final system termination
           // behavior executing cleanup is passed as a parameter to Actor.stopped
           Behaviors.stopped {
-            Behaviors.onSignal {
+            Behaviors.receiveSignal {
               case (context, PostStop) ⇒
                 cleanup(context.system.log)
                 Behaviors.same
             }
           }
       }
-    }.onSignal {
+    }.receiveSignal {
       case (ctx, PostStop) ⇒
         ctx.log.info("MCPA stopped")
         Behaviors.same
@@ -58,7 +58,7 @@ object GracefulStopDocSpec {
   object Job {
     import GracefulStopDocSpec.MasterControlProgramActor.JobControlLanguage
 
-    def job(name: String) = Behaviors.onSignal[JobControlLanguage] {
+    def job(name: String) = Behaviors.receiveSignal[JobControlLanguage] {
       case (ctx, PostStop) ⇒
         ctx.log.info("Worker {} stopped", name)
         Behaviors.same
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
index 382f9ad213..6356c55509 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
@@ -24,7 +24,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
       // #fire-and-forget-definition
       case class PrintMe(message: String)
 
-      val printerBehavior: Behavior[PrintMe] = Behaviors.immutable {
+      val printerBehavior: Behavior[PrintMe] = Behaviors.receive {
         case (ctx, PrintMe(message)) ⇒
           ctx.log.info(message)
           Behaviors.same
@@ -53,7 +53,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
       // #request-response-protocol
 
       // #request-response-respond
-      val otherBehavior = Behaviors.immutable[Request] { (ctx, msg) ⇒
+      val otherBehavior = Behaviors.receive[Request] { (ctx, msg) ⇒
         msg match {
           case Request(query, respondTo) ⇒
             // ... process query ...
@@ -108,7 +108,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
             def active(
               inProgress: Map[Int, ActorRef[URI]],
               count:      Int): Behavior[Command] = {
-              Behaviors.immutable[Command] { (_, msg) ⇒
+              Behaviors.receive[Command] { (_, msg) ⇒
                 msg match {
                   case Translate(site, replyTo) ⇒
                     val taskId = count + 1
@@ -136,7 +136,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
       }
       // #adapted-response
 
-      val backend = spawn(Behaviors.immutable[Backend.Request] { (_, msg) ⇒
+      val backend = spawn(Behaviors.receive[Backend.Request] { (_, msg) ⇒
         msg match {
           case Backend.StartTranslationJob(taskId, site, replyTo) ⇒
             replyTo ! Backend.JobStarted(taskId)
@@ -172,7 +172,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
 
     def idle(timers: TimerScheduler[Msg], target: ActorRef[Batch],
              after: FiniteDuration, maxSize: Int): Behavior[Msg] = {
-      Behaviors.immutable[Msg] { (ctx, msg) ⇒
+      Behaviors.receive[Msg] { (ctx, msg) ⇒
         timers.startSingleTimer(TimerKey, Timeout, after)
         active(Vector(msg), timers, target, after, maxSize)
       }
@@ -180,7 +180,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
 
     def active(buffer: Vector[Msg], timers: TimerScheduler[Msg],
                target: ActorRef[Batch], after: FiniteDuration, maxSize: Int): Behavior[Msg] = {
-      Behaviors.immutable[Msg] { (_, msg) ⇒
+      Behaviors.receive[Msg] { (_, msg) ⇒
         msg match {
           case Timeout ⇒
             target ! Batch(buffer)
@@ -212,7 +212,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
     case class OpenThePodBayDoorsPlease(respondTo: ActorRef[HalResponse]) extends HalCommand
     case class HalResponse(message: String)
 
-    val halBehavior = Behaviors.immutable[HalCommand] { (ctx, msg) ⇒
+    val halBehavior = Behaviors.receive[HalCommand] { (ctx, msg) ⇒
       msg match {
         case OpenThePodBayDoorsPlease(respondTo) ⇒
           respondTo ! HalResponse("I'm sorry, Dave. I'm afraid I can't do that.")
@@ -249,7 +249,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
         case Failure(ex)                   ⇒ AdaptedResponse(s"$requestId: Request failed")
       }
 
-      Behaviors.immutable { (ctx, msg) ⇒
+      Behaviors.receive { (ctx, msg) ⇒
         msg match {
           // the adapted message ends up being processed like any other
           // message sent to the actor
@@ -277,14 +277,14 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
 
     // #per-session-child
 
-    val keyCabinetBehavior: Behavior[GetKeys] = Behaviors.immutable { (ctx, msg) ⇒
+    val keyCabinetBehavior: Behavior[GetKeys] = Behaviors.receive { (ctx, msg) ⇒
       msg match {
         case GetKeys(_, respondTo) ⇒
           respondTo ! Keys()
           Behaviors.same
       }
     }
-    val drawerBehavior: Behavior[GetWallet] = Behaviors.immutable { (ctx, msg) ⇒
+    val drawerBehavior: Behavior[GetWallet] = Behaviors.receive { (ctx, msg) ⇒
       msg match {
         case GetWallet(_, respondTo) ⇒
           respondTo ! Wallet()
@@ -301,7 +301,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
     case class GetKeys(whoseKeys: String, respondTo: ActorRef[Keys])
     case class GetWallet(whoseWallet: String, respondTo: ActorRef[Wallet])
 
-    def homeBehavior = Behaviors.immutable[HomeCommand] { (ctx, msg) ⇒
+    def homeBehavior = Behaviors.receive[HomeCommand] { (ctx, msg) ⇒
       val keyCabinet: ActorRef[GetKeys] = ctx.spawn(keyCabinetBehavior, "key-cabinet")
       val drawer: ActorRef[GetWallet] = ctx.spawn(drawerBehavior, "drawer")
 
@@ -340,7 +340,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
               Behavior.same
           }
 
-        Behaviors.immutable((ctx, msg) ⇒ {
+        Behaviors.receive((ctx, msg) ⇒ {
           msg match {
             case w: Wallet ⇒
               wallet = Some(w)
@@ -370,7 +370,7 @@ class InteractionPatternsSpec extends ActorTestKit with TypedAkkaSpecWithShutdow
     // #standalone-ask
 
     // keep this out of the sample as it uses the testkit spawn
-    val cookieActorRef = spawn(Behaviors.immutable[GiveMeCookies] { (ctx, msg) ⇒
+    val cookieActorRef = spawn(Behaviors.receive[GiveMeCookies] { (ctx, msg) ⇒
       msg.replyTo ! Cookies(5)
       Behaviors.same
     })
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/IntroSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/IntroSpec.scala
index eab85384ce..5195e63709 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/IntroSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/IntroSpec.scala
@@ -27,7 +27,7 @@ object IntroSpec {
     final case class Greet(whom: String, replyTo: ActorRef[Greeted])
     final case class Greeted(whom: String)
 
-    val greeter = Behaviors.immutable[Greet] { (_, msg) ⇒
+    val greeter = Behaviors.receive[Greet] { (_, msg) ⇒
       println(s"Hello ${msg.whom}!")
       msg.replyTo ! Greeted(msg.whom)
       Behaviors.same
@@ -63,7 +63,7 @@ object IntroSpec {
       chatRoom(List.empty)
 
     private def chatRoom(sessions: List[ActorRef[SessionCommand]]): Behavior[RoomCommand] =
-      Behaviors.immutable[RoomCommand] { (ctx, msg) ⇒
+      Behaviors.receive[RoomCommand] { (ctx, msg) ⇒
         msg match {
           case GetSession(screenName, client) ⇒
             // create a child actor for further interaction with the client
@@ -83,7 +83,7 @@ object IntroSpec {
       room:       ActorRef[PublishSessionMessage],
       screenName: String,
       client:     ActorRef[SessionEvent]): Behavior[SessionCommand] =
-      Behaviors.immutable { (ctx, msg) ⇒
+      Behaviors.receive { (ctx, msg) ⇒
         msg match {
           case PostMessage(message) ⇒
             // from client, publish to others via the room
@@ -132,7 +132,7 @@ class IntroSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       import ChatRoom._
 
       val gabbler =
-        Behaviors.immutable[SessionEvent] { (_, msg) ⇒
+        Behaviors.receive[SessionEvent] { (_, msg) ⇒
           msg match {
             //#chatroom-gabbler
             // We document that the compiler warns about the missing handler for `SessionDenied`
@@ -158,7 +158,7 @@ class IntroSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           ctx.watch(gabblerRef)
           chatRoom ! GetSession("ol’ Gabbler", gabblerRef)
 
-          Behaviors.onSignal {
+          Behaviors.receiveSignal {
             case (_, Terminated(ref)) ⇒
               Behaviors.stopped
           }
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/MutableIntroSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/MutableIntroSpec.scala
index 394ebf6e88..835f3d0eae 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/MutableIntroSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/MutableIntroSpec.scala
@@ -9,8 +9,7 @@ import java.net.URLEncoder
 import java.nio.charset.StandardCharsets
 
 import akka.actor.typed._
-import akka.actor.typed.scaladsl.Behaviors
-import akka.actor.typed.scaladsl.ActorContext
+import akka.actor.typed.scaladsl.{ ActorContext, Behaviors, MutableBehavior }
 import akka.testkit.typed.scaladsl.ActorTestKit
 
 import scala.concurrent.duration._
@@ -44,9 +43,9 @@ object MutableIntroSpec {
     //#chatroom-behavior
 
     def behavior(): Behavior[RoomCommand] =
-      Behaviors.mutable[RoomCommand](ctx ⇒ new ChatRoomBehavior(ctx))
+      Behaviors.setup[RoomCommand](ctx ⇒ new ChatRoomBehavior(ctx))
 
-    class ChatRoomBehavior(ctx: ActorContext[RoomCommand]) extends Behaviors.MutableBehavior[RoomCommand] {
+    class ChatRoomBehavior(ctx: ActorContext[RoomCommand]) extends MutableBehavior[RoomCommand] {
       private var sessions: List[ActorRef[SessionCommand]] = List.empty
 
       override def onMessage(msg: RoomCommand): Behavior[RoomCommand] = {
@@ -71,17 +70,15 @@ object MutableIntroSpec {
       room:       ActorRef[PublishSessionMessage],
       screenName: String,
       client:     ActorRef[SessionEvent]): Behavior[SessionCommand] =
-      Behaviors.immutable { (ctx, msg) ⇒
-        msg match {
-          case PostMessage(message) ⇒
-            // from client, publish to others via the room
-            room ! PublishSessionMessage(screenName, message)
-            Behaviors.same
-          case NotifyClient(message) ⇒
-            // published from the room
-            client ! message
-            Behaviors.same
-        }
+      Behaviors.receiveMessage {
+        case PostMessage(message) ⇒
+          // from client, publish to others via the room
+          room ! PublishSessionMessage(screenName, message)
+          Behaviors.same
+        case NotifyClient(message) ⇒
+          // published from the room
+          client ! message
+          Behaviors.same
       }
     //#chatroom-behavior
   }
@@ -99,18 +96,16 @@ class MutableIntroSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
       import ChatRoom._
 
       val gabbler =
-        Behaviors.immutable[SessionEvent] { (_, msg) ⇒
-          msg match {
-            case SessionDenied(reason) ⇒
-              println(s"cannot start chat room session: $reason")
-              Behaviors.stopped
-            case SessionGranted(handle) ⇒
-              handle ! PostMessage("Hello World!")
-              Behaviors.same
-            case MessagePosted(screenName, message) ⇒
-              println(s"message has been posted by '$screenName': $message")
-              Behaviors.stopped
-          }
+        Behaviors.receiveMessage[SessionEvent] {
+          case SessionDenied(reason) ⇒
+            println(s"cannot start chat room session: $reason")
+            Behaviors.stopped
+          case SessionGranted(handle) ⇒
+            handle ! PostMessage("Hello World!")
+            Behaviors.same
+          case MessagePosted(screenName, message) ⇒
+            println(s"message has been posted by '$screenName': $message")
+            Behaviors.stopped
         }
       //#chatroom-gabbler
 
@@ -121,11 +116,11 @@ class MutableIntroSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           val gabblerRef = ctx.spawn(gabbler, "gabbler")
           ctx.watch(gabblerRef)
 
-          Behaviors.immutablePartial[String] {
-            case (_, "go") ⇒
+          Behaviors.receiveMessagePartial[String] {
+            case "go" ⇒
               chatRoom ! GetSession("ol’ Gabbler", gabblerRef)
               Behaviors.same
-          } onSignal {
+          } receiveSignal {
             case (_, Terminated(_)) ⇒
               println("Stopping guardian")
               Behaviors.stopped
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StashDocSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StashDocSpec.scala
index 4f6aeba465..1294dd5219 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StashDocSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StashDocSpec.scala
@@ -38,7 +38,7 @@ object StashDocSpec {
         val buffer = StashBuffer[Command](capacity = 100)
 
         def init(): Behavior[Command] =
-          Behaviors.immutable[Command] { (ctx, msg) ⇒
+          Behaviors.receive[Command] { (ctx, msg) ⇒
             msg match {
               case InitialState(value) ⇒
                 // now we are ready to handle stashed messages if any
@@ -53,7 +53,7 @@ object StashDocSpec {
           }
 
         def active(state: String): Behavior[Command] =
-          Behaviors.immutable { (ctx, msg) ⇒
+          Behaviors.receive { (ctx, msg) ⇒
             msg match {
               case Get(replyTo) ⇒
                 replyTo ! state
@@ -69,7 +69,7 @@ object StashDocSpec {
           }
 
         def saving(state: String, replyTo: ActorRef[Done]): Behavior[Command] =
-          Behaviors.immutable[Command] { (ctx, msg) ⇒
+          Behaviors.receive[Command] { (ctx, msg) ⇒
             msg match {
               case SaveSuccess ⇒
                 replyTo ! Done
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/TypedWatchingUntypedSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/TypedWatchingUntypedSpec.scala
index 2b89cce378..12d0cf72b9 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/TypedWatchingUntypedSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/TypedWatchingUntypedSpec.scala
@@ -37,13 +37,13 @@ object TypedWatchingUntypedSpec {
         // illustrating how to pass sender, toUntyped is an implicit extension method
         untyped.tell(Typed.Ping(context.self), context.self.toUntyped)
 
-        Behaviors.immutablePartial[Command] {
+        Behaviors.receivePartial[Command] {
           case (ctx, Pong) ⇒
             // it's not possible to get the sender, that must be sent in message
             // context.stop is an implicit extension method
             ctx.stop(untyped)
             Behaviors.same
-        } onSignal {
+        } receiveSignal {
           case (_, akka.actor.typed.Terminated(_)) ⇒
             Behaviors.stopped
         }
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/UntypedWatchingTypedSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/UntypedWatchingTypedSpec.scala
index dcc577edba..44961b6775 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/UntypedWatchingTypedSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/coexistence/UntypedWatchingTypedSpec.scala
@@ -57,7 +57,7 @@ object UntypedWatchingTypedSpec {
     case object Pong
 
     val behavior: Behavior[Command] =
-      Behaviors.immutable { (ctx, msg) ⇒
+      Behaviors.receive { (ctx, msg) ⇒
         msg match {
           case Ping(replyTo) ⇒
             println(s"${ctx.self} got Ping from $replyTo")
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/Behavior.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/Behavior.scala
index d04e6ad059..a2d817d7a7 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/Behavior.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/Behavior.scala
@@ -50,6 +50,22 @@ sealed abstract class Behavior[T] { behavior ⇒
  * set of behaviors available through the DSLs in [[akka.actor.typed.scaladsl.Behaviors]] and [[akka.actor.typed.javadsl.Behaviors]]
  */
 abstract class ExtensibleBehavior[T] extends Behavior[T] {
+  /**
+   * Process an incoming message and return the next behavior.
+   *
+   * The returned behavior can in addition to normal behaviors be one of the
+   * canned special objects:
+   *
+   *  * returning `stopped` will terminate this Behavior
+   *  * returning `same` designates to reuse the current Behavior
+   *  * returning `unhandled` keeps the same Behavior and signals that the message was not yet handled
+   *
+   * Code calling this method should use [[Behavior$]] `canonicalize` to replace
+   * the special objects with real Behaviors.
+   */
+  @throws(classOf[Exception])
+  def receive(ctx: ActorContext[T], msg: T): Behavior[T]
+
   /**
    * Process an incoming [[Signal]] and return the next behavior. This means
    * that all lifecycle hooks, ReceiveTimeout, Terminated and Failed messages
@@ -67,23 +83,6 @@ abstract class ExtensibleBehavior[T] extends Behavior[T] {
    */
   @throws(classOf[Exception])
   def receiveSignal(ctx: ActorContext[T], msg: Signal): Behavior[T]
-
-  /**
-   * Process an incoming message and return the next behavior.
-   *
-   * The returned behavior can in addition to normal behaviors be one of the
-   * canned special objects:
-   *
-   *  * returning `stopped` will terminate this Behavior
-   *  * returning `same` designates to reuse the current Behavior
-   *  * returning `unhandled` keeps the same Behavior and signals that the message was not yet handled
-   *
-   * Code calling this method should use [[Behavior$]] `canonicalize` to replace
-   * the special objects with real Behaviors.
-   */
-  @throws(classOf[Exception])
-  def receiveMessage(ctx: ActorContext[T], msg: T): Behavior[T]
-
 }
 
 object Behavior {
@@ -97,7 +96,7 @@ object Behavior {
      *
      * Example:
      * {{{
-     * immutable[String] { (ctx, msg) => println(msg); same }.widen[Number] {
+     * receive[String] { (ctx, msg) => println(msg); same }.widen[Number] {
      *   case b: BigDecimal => s"BigDecimal(&dollar;b)"
      *   case i: BigInteger => s"BigInteger(&dollar;i)"
      *   // drop all other kinds of Number
@@ -341,7 +340,7 @@ object Behavior {
       case ext: ExtensibleBehavior[T] ⇒
         val possiblyDeferredResult = msg match {
           case signal: Signal ⇒ ext.receiveSignal(ctx, signal)
-          case m              ⇒ ext.receiveMessage(ctx, m.asInstanceOf[T])
+          case m              ⇒ ext.receive(ctx, m.asInstanceOf[T])
         }
         start(possiblyDeferredResult, ctx)
     }
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/BehaviorImpl.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/BehaviorImpl.scala
index 89a5c80df9..16fe86162d 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/BehaviorImpl.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/BehaviorImpl.scala
@@ -5,7 +5,7 @@
 package akka.actor.typed
 package internal
 
-import akka.util.LineNumbers
+import akka.util.{ ConstantFun, LineNumbers }
 import akka.annotation.InternalApi
 import akka.actor.typed.{ ActorContext ⇒ AC }
 import akka.actor.typed.scaladsl.{ ActorContext ⇒ SAC }
@@ -18,8 +18,8 @@ import scala.reflect.ClassTag
 @InternalApi private[akka] object BehaviorImpl {
   import Behavior._
 
-  private val _nullFun = (_: Any) ⇒ null
-  private def nullFun[T] = _nullFun.asInstanceOf[Any ⇒ T]
+  private[this] final val _any2null = (_: Any) ⇒ null
+  private[this] final def any2null[T] = _any2null.asInstanceOf[Any ⇒ T]
 
   implicit class ContextAs[T](val ctx: AC[T]) extends AnyVal {
     def as[U]: AC[U] = ctx.asInstanceOf[AC[U]]
@@ -46,8 +46,8 @@ import scala.reflect.ClassTag
     override def receiveSignal(ctx: AC[U], signal: Signal): Behavior[U] =
       widen(Behavior.interpretSignal(behavior, ctx.as[T], signal), ctx.as[T])
 
-    override def receiveMessage(ctx: AC[U], msg: U): Behavior[U] =
-      matcher.applyOrElse(msg, nullFun) match {
+    override def receive(ctx: AC[U], msg: U): Behavior[U] =
+      matcher.applyOrElse(msg, any2null) match {
         case null        ⇒ unhandled
         case transformed ⇒ widen(Behavior.interpretMessage(behavior, ctx.as[T], transformed), ctx.as[T])
       }
@@ -55,7 +55,7 @@ import scala.reflect.ClassTag
     override def toString: String = s"${behavior.toString}.widen(${LineNumbers(matcher)})"
   }
 
-  class ImmutableBehavior[T](
+  class ReceiveBehavior[T](
     val onMessage: (SAC[T], T) ⇒ Behavior[T],
     onSignal:      PartialFunction[(SAC[T], Signal), Behavior[T]] = Behavior.unhandledSignal.asInstanceOf[PartialFunction[(SAC[T], Signal), Behavior[T]]])
     extends ExtensibleBehavior[T] {
@@ -63,9 +63,27 @@ import scala.reflect.ClassTag
     override def receiveSignal(ctx: AC[T], msg: Signal): Behavior[T] =
       onSignal.applyOrElse((ctx.asScala, msg), Behavior.unhandledSignal.asInstanceOf[PartialFunction[(SAC[T], Signal), Behavior[T]]])
 
-    override def receiveMessage(ctx: AC[T], msg: T) = onMessage(ctx.asScala, msg)
+    override def receive(ctx: AC[T], msg: T) = onMessage(ctx.asScala, msg)
 
-    override def toString = s"Immutable(${LineNumbers(onMessage)})"
+    override def toString = s"Receive(${LineNumbers(onMessage)})"
+  }
+
+  /**
+   * Similar to [[ReceiveBehavior]] however `onMessage` does not accept context.
+   * We implement it separately in order to be able to avoid wrapping each function in
+   * another function which drops the context parameter.
+   */
+  class ReceiveMessageBehavior[T](
+    val onMessage: T ⇒ Behavior[T],
+    onSignal:      PartialFunction[(SAC[T], Signal), Behavior[T]] = Behavior.unhandledSignal.asInstanceOf[PartialFunction[(SAC[T], Signal), Behavior[T]]])
+    extends ExtensibleBehavior[T] {
+
+    override def receive(ctx: AC[T], msg: T) = onMessage(msg)
+
+    override def receiveSignal(ctx: AC[T], msg: Signal): Behavior[T] =
+      onSignal.applyOrElse((ctx.asScala, msg), Behavior.unhandledSignal.asInstanceOf[PartialFunction[(SAC[T], Signal), Behavior[T]]])
+
+    override def toString = s"ReceiveMessage(${LineNumbers(onMessage)})"
   }
 
   def tap[T](
@@ -81,8 +99,8 @@ import scala.reflect.ClassTag
         onSignal(ctx, sig)
         true
       },
-      afterMessage = (_, _, b) ⇒ b, // TODO optimize by using more ConstantFun
-      afterSignal = (_, _, b) ⇒ b,
+      afterMessage = ConstantFun.scalaAnyThreeToThird,
+      afterSignal = ConstantFun.scalaAnyThreeToThird,
       behavior)(ClassTag(classOf[Any]))
   }
 
@@ -141,7 +159,7 @@ import scala.reflect.ClassTag
       intercept(afterSignal(ctx.asScala, signal, next), ctx)
     }
 
-    override def receiveMessage(ctx: AC[T], msg: T): Behavior[T] = {
+    override def receive(ctx: AC[T], msg: T): Behavior[T] = {
       msg match {
         case m: U ⇒
           val msg2 = beforeOnMessage(ctx.asScala.asInstanceOf[SAC[U]], m)
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/Restarter.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/Restarter.scala
index 6c51b146bf..9a5707cdc8 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/Restarter.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/Restarter.scala
@@ -92,7 +92,7 @@ import scala.util.control.NonFatal
     } catch handleException(ctx, behavior)
   }
 
-  override def receiveMessage(ctx: ActorContext[T], msg: T): Behavior[T] = {
+  override def receive(ctx: ActorContext[T], msg: T): Behavior[T] = {
     try {
       val b = Behavior.interpretMessage(behavior, ctx, msg)
       supervise(b, ctx)
@@ -272,7 +272,7 @@ import scala.util.control.NonFatal
       super.receiveSignal(ctx, signal)
   }
 
-  override def receiveMessage(ctx: ActorContext[Any], msg: Any): Behavior[Any] = {
+  override def receive(ctx: ActorContext[Any], msg: Any): Behavior[Any] = {
     // intercept the scheduled messages and drop incoming messages if we are in backoff mode
     msg match {
       case ScheduledRestart ⇒
@@ -290,7 +290,7 @@ import scala.util.control.NonFatal
           ctx.asScala.system.toUntyped.eventStream.publish(Dropped(msg, ctx.asScala.self))
           Behavior.same
         } else
-          super.receiveMessage(ctx, msg)
+          super.receive(ctx, msg)
     }
   }
 
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/receptionist/LocalReceptionist.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/receptionist/LocalReceptionist.scala
index b9b8b04cc4..2ec0179d23 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/internal/receptionist/LocalReceptionist.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/internal/receptionist/LocalReceptionist.scala
@@ -8,7 +8,7 @@ import akka.actor.typed.{ ActorRef, Behavior, Terminated }
 import akka.actor.typed.receptionist.Receptionist._
 import akka.actor.typed.receptionist.ServiceKey
 import akka.actor.typed.scaladsl.{ ActorContext, Behaviors }
-import akka.actor.typed.scaladsl.Behaviors.{ immutable, same }
+import akka.actor.typed.scaladsl.Behaviors.{ receive, same }
 import akka.annotation.InternalApi
 import akka.util.TypedMultiMap
 
@@ -55,12 +55,11 @@ private[akka] object LocalReceptionist extends ReceptionistBehaviorProvider {
     def watchWith(ctx: ActorContext[Any], target: ActorRef[_], msg: InternalCommand): Unit =
       ctx.spawnAnonymous[Nothing](Behaviors.setup[Nothing] { innerCtx ⇒
         innerCtx.watch(target)
-        Behaviors.immutable[Nothing]((_, _) ⇒ Behaviors.same)
-          .onSignal {
-            case (_, Terminated(`target`)) ⇒
-              ctx.self ! msg
-              Behaviors.stopped
-          }
+        Behaviors.receiveSignal[Nothing] {
+          case (_, Terminated(`target`)) ⇒
+            ctx.self ! msg
+            Behaviors.stopped
+        }
       })
 
     // Helper that makes sure that subscribers are notified when an entry is changed
@@ -111,7 +110,7 @@ private[akka] object LocalReceptionist extends ReceptionistBehaviorProvider {
         next(newSubscriptions = subscriptions.removed(key)(subscriber))
     }
 
-    immutable[Any] { (ctx, msg) ⇒
+    receive[Any] { (ctx, msg) ⇒
       msg match {
         case cmd: Command         ⇒ onCommand(ctx, cmd)
         case cmd: InternalCommand ⇒ onInternal(ctx, cmd)
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 587d0187c5..b02ee2972b 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
@@ -251,7 +251,7 @@ private class BuiltBehavior[T](
   private val signalHandlers:  List[Case[T, Signal]]
 ) extends ExtensibleBehavior[T] {
 
-  override def receiveMessage(ctx: typed.ActorContext[T], msg: T): Behavior[T] = receive[T](ctx.asJava, msg, messageHandlers)
+  override def receive(ctx: typed.ActorContext[T], msg: T): Behavior[T] = receive[T](ctx.asJava, msg, messageHandlers)
 
   override def receiveSignal(ctx: typed.ActorContext[T], msg: Signal): Behavior[T] = receive[Signal](ctx.asJava, msg, signalHandlers)
 
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/Behaviors.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/Behaviors.scala
index 4a165fff30..6dfff4c1c3 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/Behaviors.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/Behaviors.scala
@@ -7,18 +7,18 @@ package akka.actor.typed.javadsl
 import java.util.function.{ Function ⇒ JFunction }
 
 import scala.reflect.ClassTag
-import akka.util.OptionVal
+import akka.util.ConstantFun
 import akka.japi.function.{ Function2 ⇒ JapiFunction2 }
-import akka.japi.function.{ Procedure, Procedure2 }
+import akka.japi.function.Procedure2
 import akka.japi.pf.PFBuilder
 import akka.actor.typed.Behavior
 import akka.actor.typed.ExtensibleBehavior
 import akka.actor.typed.Signal
 import akka.actor.typed.ActorRef
 import akka.actor.typed.SupervisorStrategy
-import akka.actor.typed.scaladsl.{ ActorContext ⇒ SAC }
 import akka.actor.typed.internal.{ BehaviorImpl, LoggingBehaviorImpl, Supervisor, TimerSchedulerImpl }
-import akka.annotation.ApiMayChange
+import akka.annotation.{ ApiMayChange, DoNotInherit }
+
 import scala.collection.JavaConverters._
 /**
  * Factories for [[akka.actor.typed.Behavior]].
@@ -26,12 +26,14 @@ import scala.collection.JavaConverters._
 @ApiMayChange
 object Behaviors {
 
-  private val _unitFunction = (_: SAC[Any], _: Any) ⇒ ()
-  private def unitFunction[T] = _unitFunction.asInstanceOf[((SAC[T], Signal) ⇒ Unit)]
+  private[this] val _two2same = new JapiFunction2[ActorContext[Any], Any, Behavior[Any]] {
+    override def apply(context: ActorContext[Any], msg: Any): Behavior[Any] = same
+  }
+  private[this] def two2same[T] = _two2same.asInstanceOf[JapiFunction2[ActorContext[T], T, Behavior[T]]]
 
   /**
    * `setup` is a factory for a behavior. Creation of the behavior instance is deferred until
-   * the actor is started, as opposed to [[Behaviors#immutable]] that creates the behavior instance
+   * the actor is started, as opposed to [[Behaviors#receive]] that creates the behavior instance
    * immediately before the actor is running. The `factory` function pass the `ActorContext`
    * as parameter and that can for example be used for spawning child actors.
    *
@@ -43,55 +45,6 @@ object Behaviors {
   def setup[T](factory: akka.japi.function.Function[ActorContext[T], Behavior[T]]): Behavior[T] =
     Behavior.DeferredBehavior(ctx ⇒ factory.apply(ctx.asJava))
 
-  /**
-   * Factory for creating a [[MutableBehavior]] that typically holds mutable state as
-   * instance variables in the concrete [[MutableBehavior]] implementation class.
-   *
-   * Creation of the behavior instance is deferred, i.e. it is created via the `factory`
-   * function. The reason for the deferred creation is to avoid sharing the same instance in
-   * multiple actors, and to create a new instance when the actor is restarted.
-   *
-   * @param factory
-   *          behavior factory that takes the child actor’s context as argument
-   * @return the deferred behavior
-   */
-  def mutable[T](factory: akka.japi.function.Function[ActorContext[T], MutableBehavior[T]]): Behavior[T] =
-    setup(factory)
-
-  /**
-   * Mutable behavior can be implemented by extending this class and implement the
-   * abstract method [[MutableBehavior#onMessage]] and optionally override
-   * [[MutableBehavior#onSignal]].
-   *
-   * Instances of this behavior should be created via [[Behaviors#mutable]] and if
-   * the [[ActorContext]] is needed it can be passed as a constructor parameter
-   * from the factory function.
-   *
-   * @see [[Behaviors#mutable]]
-   */
-  abstract class MutableBehavior[T] extends ExtensibleBehavior[T] {
-    private var _receive: OptionVal[Receive[T]] = OptionVal.None
-    private def receive: Receive[T] = _receive match {
-      case OptionVal.None ⇒
-        val receive = createReceive
-        _receive = OptionVal.Some(receive)
-        receive
-      case OptionVal.Some(r) ⇒ r
-    }
-
-    @throws(classOf[Exception])
-    override final def receiveMessage(ctx: akka.actor.typed.ActorContext[T], msg: T): Behavior[T] =
-      receive.receiveMessage(msg)
-
-    @throws(classOf[Exception])
-    override final def receiveSignal(ctx: akka.actor.typed.ActorContext[T], msg: Signal): Behavior[T] =
-      receive.receiveSignal(msg)
-
-    def createReceive: Receive[T]
-
-    def receiveBuilder: ReceiveBuilder[T] = ReceiveBuilder.create
-  }
-
   /**
    * Return this behavior from message processing in order to advise the
    * system to reuse the previous behavior. This is provided in order to
@@ -153,8 +106,28 @@ object Behaviors {
    * State is updated by returning a new behavior that holds the new immutable
    * state.
    */
-  def immutable[T](onMessage: JapiFunction2[ActorContext[T], T, Behavior[T]]): Behavior[T] =
-    new BehaviorImpl.ImmutableBehavior((ctx, msg) ⇒ onMessage.apply(ctx.asJava, msg))
+  def receive[T](onMessage: JapiFunction2[ActorContext[T], T, Behavior[T]]): Behavior[T] =
+    new BehaviorImpl.ReceiveBehavior((ctx, msg) ⇒ onMessage.apply(ctx.asJava, msg))
+
+  /**
+   * Simplified version of [[receive]] with only a single argument - the message
+   * to be handled. Useful for when the context is already accessible by other means,
+   * like being wrapped in an [[setup]] or similar.
+   *
+   * Construct an actor behavior that can react to incoming messages but not to
+   * lifecycle signals. After spawning this actor from another actor (or as the
+   * guardian of an [[akka.actor.typed.ActorSystem]]) it will be executed within an
+   * [[ActorContext]] that allows access to the system, spawning and watching
+   * other actors, etc.
+   *
+   * This constructor is called immutable because the behavior instance doesn't
+   * have or close over any mutable state. Processing the next message
+   * results in a new behavior that can potentially be different from this one.
+   * State is updated by returning a new behavior that holds the new immutable
+   * state.
+   */
+  def receiveMessage[T](onMessage: akka.japi.Function[T, Behavior[T]]): Behavior[T] =
+    new BehaviorImpl.ReceiveBehavior((_, msg) ⇒ onMessage.apply(msg))
 
   /**
    * Construct an actor behavior that can react to both incoming messages and
@@ -169,10 +142,10 @@ object Behaviors {
    * State is updated by returning a new behavior that holds the new immutable
    * state.
    */
-  def immutable[T](
+  def receive[T](
     onMessage: JapiFunction2[ActorContext[T], T, Behavior[T]],
     onSignal:  JapiFunction2[ActorContext[T], Signal, Behavior[T]]): Behavior[T] = {
-    new BehaviorImpl.ImmutableBehavior(
+    new BehaviorImpl.ReceiveBehavior(
       (ctx, msg) ⇒ onMessage.apply(ctx.asJava, msg),
       { case (ctx, sig) ⇒ onSignal.apply(ctx.asJava, sig) })
   }
@@ -189,16 +162,13 @@ object Behaviors {
    * @param type the supertype of all messages accepted by this behavior
    * @return the behavior builder
    */
-  def immutable[T](`type`: Class[T]): BehaviorBuilder[T] = BehaviorBuilder.create[T]
+  def receive[T](`type`: Class[T]): BehaviorBuilder[T] = BehaviorBuilder.create[T]
 
   /**
    * Construct an actor behavior that can react to lifecycle signals only.
    */
-  def onSignal[T](handler: JapiFunction2[ActorContext[T], Signal, Behavior[T]]): Behavior[T] = {
-    val jSame = new JapiFunction2[ActorContext[T], T, Behavior[T]] {
-      override def apply(ctx: ActorContext[T], msg: T) = same
-    }
-    immutable(jSame, handler)
+  def receiveSignal[T](handler: JapiFunction2[ActorContext[T], Signal, Behavior[T]]): Behavior[T] = {
+    receive(two2same, handler)
   }
 
   /**
@@ -225,7 +195,7 @@ object Behaviors {
   def monitor[T](monitor: ActorRef[T], behavior: Behavior[T]): Behavior[T] = {
     BehaviorImpl.tap(
       (ctx, msg) ⇒ monitor ! msg,
-      unitFunction,
+      ConstantFun.scalaAnyTwoToUnit,
       behavior)
   }
 
@@ -313,10 +283,9 @@ object Behaviors {
   def withTimers[T](factory: akka.japi.function.Function[TimerScheduler[T], Behavior[T]]): Behavior[T] =
     TimerSchedulerImpl.withTimers(timers ⇒ factory.apply(timers))
 
-  trait Receive[T] {
-    def receiveMessage(msg: T): Behavior[T]
-    def receiveSignal(msg: Signal): Behavior[T]
-  }
+  /** A specialized "receive" behavior that is implemented using message matching builders. */
+  @DoNotInherit
+  trait Receive[T] extends ExtensibleBehavior[T]
 
   /**
    * Provide a MDC ("Mapped Diagnostic Context") for logging from the actor.
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/MutableBehavior.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/MutableBehavior.scala
new file mode 100644
index 0000000000..0c56170041
--- /dev/null
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/MutableBehavior.scala
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package akka.actor.typed.javadsl
+
+import akka.actor.typed.{ Behavior, ExtensibleBehavior, Signal }
+import akka.actor.typed.javadsl.Behaviors.Receive
+import akka.util.OptionVal
+
+/**
+ * Mutable behavior can be implemented by extending this class and implement the
+ * abstract method [[MutableBehavior#onMessage]] and optionally override
+ * [[MutableBehavior#onSignal]].
+ *
+ * Instances of this behavior should be created via [[Behaviors#setup]] and if
+ * the [[ActorContext]] is needed it can be passed as a constructor parameter
+ * from the factory function.
+ *
+ * @see [[Behaviors#setup]]
+ */
+abstract class MutableBehavior[T] extends ExtensibleBehavior[T] {
+  private var _receive: OptionVal[Receive[T]] = OptionVal.None
+  private def receive: Receive[T] = _receive match {
+    case OptionVal.None ⇒
+      val receive = createReceive
+      _receive = OptionVal.Some(receive)
+      receive
+    case OptionVal.Some(r) ⇒ r
+  }
+
+  @throws(classOf[Exception])
+  override final def receive(ctx: akka.actor.typed.ActorContext[T], msg: T): Behavior[T] =
+    receive.receive(ctx, msg)
+
+  @throws(classOf[Exception])
+  override final def receiveSignal(ctx: akka.actor.typed.ActorContext[T], msg: Signal): Behavior[T] =
+    receive.receiveSignal(ctx, msg)
+
+  def createReceive: Receive[T]
+
+  def receiveBuilder: ReceiveBuilder[T] = ReceiveBuilder.create
+}
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/ReceiveBuilder.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/ReceiveBuilder.scala
index 661b9f85ea..55132f4133 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/ReceiveBuilder.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/ReceiveBuilder.scala
@@ -9,10 +9,11 @@ import akka.japi.function.{ Creator, Function, Predicate }
 import akka.actor.typed.javadsl.Behaviors.Receive
 import akka.actor.typed.{ Behavior, Signal }
 import ReceiveBuilder._
+import akka.actor.typed
 import akka.annotation.InternalApi
 
 /**
- * Used when implementing [[Behaviors.MutableBehavior]].
+ * Used when implementing [[MutableBehavior]].
  *
  * When handling a message or signal, this [[Behavior]] will consider all handlers in the order they were added,
  * looking for the first handler for which both the type and the (optional) predicate match.
@@ -145,16 +146,18 @@ object ReceiveBuilder {
 }
 
 /**
- * Receive type for [[Behaviors.MutableBehavior]]
+ * Receive type for [[MutableBehavior]]
  */
-private class BuiltReceive[T](
+private final class BuiltReceive[T](
   private val messageHandlers: List[Case[T, T]],
   private val signalHandlers:  List[Case[T, Signal]]
 ) extends Receive[T] {
 
-  override def receiveMessage(msg: T): Behavior[T] = receive[T](msg, messageHandlers)
+  override def receive(ctx: typed.ActorContext[T], msg: T): Behavior[T] = receive[T](msg, messageHandlers)
+  //  override def receiveMessage(msg: T): Behavior[T] = receive[T](msg, messageHandlers)
 
-  override def receiveSignal(msg: Signal): Behavior[T] = receive[Signal](msg, signalHandlers)
+  override def receiveSignal(ctx: typed.ActorContext[T], msg: Signal): Behavior[T] = receive[Signal](msg, signalHandlers)
+  //  override def receiveSignal(msg: Signal): Behavior[T] = receive[Signal](msg, signalHandlers)
 
   @tailrec
   private def receive[M](msg: M, handlers: List[Case[T, M]]): Behavior[T] =
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/Behaviors.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/Behaviors.scala
index 76c58c819d..b1e5c24aec 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/Behaviors.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/Behaviors.scala
@@ -5,11 +5,10 @@
 package akka.actor.typed
 package scaladsl
 
-import akka.annotation.{ ApiMayChange, InternalApi }
 import akka.actor.typed.internal.{ BehaviorImpl, LoggingBehaviorImpl, Supervisor, TimerSchedulerImpl }
+import akka.annotation.{ ApiMayChange, DoNotInherit, InternalApi }
 
 import scala.reflect.ClassTag
-import scala.util.control.Exception.Catcher
 
 /**
  * Factories for [[akka.actor.typed.Behavior]].
@@ -22,7 +21,7 @@ object Behaviors {
 
   /**
    * `setup` is a factory for a behavior. Creation of the behavior instance is deferred until
-   * the actor is started, as opposed to [[Behaviors.immutable]] that creates the behavior instance
+   * the actor is started, as opposed to [[Behaviors.receive]] that creates the behavior instance
    * immediately before the actor is running. The `factory` function pass the `ActorContext`
    * as parameter and that can for example be used for spawning child actors.
    *
@@ -34,71 +33,6 @@ object Behaviors {
   def setup[T](factory: ActorContext[T] ⇒ Behavior[T]): Behavior[T] =
     Behavior.DeferredBehavior(factory)
 
-  /**
-   * Factory for creating a [[MutableBehavior]] that typically holds mutable state as
-   * instance variables in the concrete [[MutableBehavior]] implementation class.
-   *
-   * Creation of the behavior instance is deferred, i.e. it is created via the `factory`
-   * function. The reason for the deferred creation is to avoid sharing the same instance in
-   * multiple actors, and to create a new instance when the actor is restarted.
-   *
-   * @param factory behavior factory that takes the child actor’s context as argument
-   * @return the deferred behavior
-   */
-  def mutable[T](factory: ActorContext[T] ⇒ MutableBehavior[T]): Behavior[T] =
-    setup(factory)
-
-  /**
-   * Mutable behavior can be implemented by extending this class and implement the
-   * abstract method [[MutableBehavior#onMessage]] and optionally override
-   * [[MutableBehavior#onSignal]].
-   *
-   * Instances of this behavior should be created via [[Behaviors#Mutable]] and if
-   * the [[ActorContext]] is needed it can be passed as a constructor parameter
-   * from the factory function.
-   *
-   * @see [[Behaviors#Mutable]]
-   */
-  abstract class MutableBehavior[T] extends ExtensibleBehavior[T] {
-    @throws(classOf[Exception])
-    override final def receiveMessage(ctx: akka.actor.typed.ActorContext[T], msg: T): Behavior[T] =
-      onMessage(msg)
-
-    /**
-     * Implement this method to process an incoming message and return the next behavior.
-     *
-     * The returned behavior can in addition to normal behaviors be one of the canned special objects:
-     * <ul>
-     * <li>returning `stopped` will terminate this Behavior</li>
-     * <li>returning `this` or `same` designates to reuse the current Behavior</li>
-     * <li>returning `unhandled` keeps the same Behavior and signals that the message was not yet handled</li>
-     * </ul>
-     *
-     */
-    @throws(classOf[Exception])
-    def onMessage(msg: T): Behavior[T]
-
-    @throws(classOf[Exception])
-    override final def receiveSignal(ctx: akka.actor.typed.ActorContext[T], msg: Signal): Behavior[T] =
-      onSignal.applyOrElse(msg, { case msg ⇒ Behavior.unhandled }: PartialFunction[Signal, Behavior[T]])
-
-    /**
-     * Override this method to process an incoming [[akka.actor.typed.Signal]] and return the next behavior.
-     * This means that all lifecycle hooks, ReceiveTimeout, Terminated and Failed messages
-     * can initiate a behavior change.
-     *
-     * The returned behavior can in addition to normal behaviors be one of the canned special objects:
-     *
-     *  * returning `stopped` will terminate this Behavior
-     *  * returning `this` or `same` designates to reuse the current Behavior
-     *  * returning `unhandled` keeps the same Behavior and signals that the message was not yet handled
-     *
-     * By default, partial function is empty and does not handle any signals.
-     */
-    @throws(classOf[Exception])
-    def onSignal: PartialFunction[Signal, Behavior[T]] = PartialFunction.empty
-  }
-
   /**
    * Return this behavior from message processing in order to advise the
    * system to reuse the previous behavior. This is provided in order to
@@ -158,27 +92,48 @@ object Behaviors {
    * need and in fact should not use (close over) mutable variables, but instead
    * return a potentially different behavior encapsulating any state changes.
    */
-  def immutable[T](onMessage: (ActorContext[T], T) ⇒ Behavior[T]): Immutable[T] =
-    new Immutable(onMessage)
+  def receive[T](onMessage: (ActorContext[T], T) ⇒ Behavior[T]): Receive[T] =
+    new ReceiveImpl(onMessage)
 
-  final class Immutable[T](onMessage: (ActorContext[T], T) ⇒ Behavior[T])
-    extends BehaviorImpl.ImmutableBehavior[T](onMessage) {
-
-    def onSignal(onSignal: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T] =
-      new BehaviorImpl.ImmutableBehavior(onMessage, onSignal)
-  }
+  /**
+   * Simplified version of [[Receive]] with only a single argument - the message
+   * to be handled. Useful for when the context is already accessible by other means,
+   * like being wrapped in an [[setup]] or similar.
+   *
+   * Construct an actor behavior that can react to both incoming messages and
+   * lifecycle signals. After spawning this actor from another actor (or as the
+   * guardian of an [[akka.actor.typed.ActorSystem]]) it will be executed within an
+   * [[ActorContext]] that allows access to the system, spawning and watching
+   * other actors, etc.
+   *
+   * This constructor is called immutable because the behavior instance does not
+   * need and in fact should not use (close over) mutable variables, but instead
+   * return a potentially different behavior encapsulating any state changes.
+   */
+  def receiveMessage[T](onMessage: T ⇒ Behavior[T]): Receive[T] =
+    new ReceiveMessageImpl(onMessage)
 
   /**
    * Construct an immutable actor behavior from a partial message handler which treats undefined messages as unhandled.
    */
-  def immutablePartial[T](onMessage: PartialFunction[(ActorContext[T], T), Behavior[T]]): Immutable[T] =
-    Behaviors.immutable[T] { (ctx, t) ⇒ onMessage.applyOrElse((ctx, t), (_: (ActorContext[T], T)) ⇒ Behaviors.unhandled[T]) }
+  def receivePartial[T](onMessage: PartialFunction[(ActorContext[T], T), Behavior[T]]): Receive[T] =
+    Behaviors.receive[T] { (ctx, t) ⇒
+      onMessage.applyOrElse((ctx, t), (_: (ActorContext[T], T)) ⇒ Behaviors.unhandled[T])
+    }
+
+  /**
+   * Construct an immutable actor behavior from a partial message handler which treats undefined messages as unhandled.
+   */
+  def receiveMessagePartial[T](onMessage: PartialFunction[T, Behavior[T]]): Receive[T] =
+    Behaviors.receive[T] { (_, t) ⇒
+      onMessage.applyOrElse(t, (_: T) ⇒ Behaviors.unhandled[T])
+    }
 
   /**
    * Construct an actor behavior that can react to lifecycle signals only.
    */
-  def onSignal[T](handler: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T] =
-    immutable[T]((_, _) ⇒ same).onSignal(handler)
+  def receiveSignal[T](handler: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T] =
+    receive[T]((_, _) ⇒ same).receiveSignal(handler)
 
   /**
    * This type of Behavior wraps another Behavior while allowing you to perform
@@ -263,4 +218,30 @@ object Behaviors {
   // TODO
   // final case class Selective[T](timeout: FiniteDuration, selector: PartialFunction[T, Behavior[T]], onTimeout: () ⇒ Behavior[T])
 
+  /**
+   * Immutable behavior that exposes additional fluent DSL methods
+   * to further change the message or signal reception behavior.
+   */
+  @DoNotInherit
+  trait Receive[T] extends ExtensibleBehavior[T] {
+    def receiveSignal(onSignal: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T]
+
+    // TODO orElse can be defined here
+  }
+
+  @InternalApi
+  private[akka] final class ReceiveImpl[T](onMessage: (ActorContext[T], T) ⇒ Behavior[T])
+    extends BehaviorImpl.ReceiveBehavior[T](onMessage) with Receive[T] {
+
+    override def receiveSignal(onSignal: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T] =
+      new BehaviorImpl.ReceiveBehavior(onMessage, onSignal)
+  }
+  @InternalApi
+  private[akka] final class ReceiveMessageImpl[T](onMessage: T ⇒ Behavior[T])
+    extends BehaviorImpl.ReceiveMessageBehavior[T](onMessage) with Receive[T] {
+
+    override def receiveSignal(onSignal: PartialFunction[(ActorContext[T], Signal), Behavior[T]]): Behavior[T] =
+      new BehaviorImpl.ReceiveMessageBehavior[T](onMessage, onSignal)
+  }
+
 }
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/MutableBehavior.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/MutableBehavior.scala
new file mode 100644
index 0000000000..94dc90b604
--- /dev/null
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/MutableBehavior.scala
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2018 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package akka.actor.typed.scaladsl
+
+import akka.actor.typed.{ Behavior, ExtensibleBehavior, Signal }
+
+/**
+ * Mutable behavior can be implemented by extending this class and implement the
+ * abstract method [[MutableBehavior#onMessage]] and optionally override
+ * [[MutableBehavior#onSignal]].
+ *
+ * Instances of this behavior should be created via [[Behaviors#setup]] and if
+ * the [[ActorContext]] is needed it can be passed as a constructor parameter
+ * from the factory function.
+ *
+ * @see [[Behaviors#setup]]
+ */
+abstract class MutableBehavior[T] extends ExtensibleBehavior[T] {
+  @throws(classOf[Exception])
+  override final def receive(ctx: akka.actor.typed.ActorContext[T], msg: T): Behavior[T] =
+    onMessage(msg)
+
+  /**
+   * Implement this method to process an incoming message and return the next behavior.
+   *
+   * The returned behavior can in addition to normal behaviors be one of the canned special objects:
+   * <ul>
+   * <li>returning `stopped` will terminate this Behavior</li>
+   * <li>returning `this` or `same` designates to reuse the current Behavior</li>
+   * <li>returning `unhandled` keeps the same Behavior and signals that the message was not yet handled</li>
+   * </ul>
+   *
+   */
+  @throws(classOf[Exception])
+  def onMessage(msg: T): Behavior[T]
+
+  @throws(classOf[Exception])
+  override final def receiveSignal(ctx: akka.actor.typed.ActorContext[T], msg: Signal): Behavior[T] =
+    onSignal.applyOrElse(msg, { case _ ⇒ Behavior.unhandled }: PartialFunction[Signal, Behavior[T]])
+
+  /**
+   * Override this method to process an incoming [[akka.actor.typed.Signal]] and return the next behavior.
+   * This means that all lifecycle hooks, ReceiveTimeout, Terminated and Failed messages
+   * can initiate a behavior change.
+   *
+   * The returned behavior can in addition to normal behaviors be one of the canned special objects:
+   *
+   *  * returning `stopped` will terminate this Behavior
+   *  * returning `this` or `same` designates to reuse the current Behavior
+   *  * returning `unhandled` keeps the same Behavior and signals that the message was not yet handled
+   *
+   * By default, partial function is empty and does not handle any signals.
+   */
+  @throws(classOf[Exception])
+  def onSignal: PartialFunction[Signal, Behavior[T]] = PartialFunction.empty
+}
diff --git a/akka-actor/src/main/scala/akka/actor/AbstractActor.scala b/akka-actor/src/main/scala/akka/actor/AbstractActor.scala
index b56776d5ee..8041ac8a2a 100644
--- a/akka-actor/src/main/scala/akka/actor/AbstractActor.scala
+++ b/akka-actor/src/main/scala/akka/actor/AbstractActor.scala
@@ -28,7 +28,8 @@ object AbstractActor {
      * Composes this `Receive` with a fallback which gets applied
      * where this partial function is not defined.
      */
-    def orElse(other: Receive): Receive = new Receive(onMessage.orElse(other.onMessage))
+    def orElse(other: Receive): Receive =
+      new Receive(onMessage.orElse(other.onMessage))
   }
 
   /**
diff --git a/akka-actor/src/main/scala/akka/util/ConstantFun.scala b/akka-actor/src/main/scala/akka/util/ConstantFun.scala
index bea14d6a7d..8f82aeafc9 100644
--- a/akka-actor/src/main/scala/akka/util/ConstantFun.scala
+++ b/akka-actor/src/main/scala/akka/util/ConstantFun.scala
@@ -31,6 +31,7 @@ import akka.japi.{ Pair ⇒ JPair }
   def scalaAnyTwoToUnit[A, B]: (A, B) ⇒ Unit = two2unit
   def scalaAnyTwoToTrue[A, B]: (A, B) ⇒ Boolean = two2true
   def scalaAnyThreeToFalse[A, B, C]: (A, B, C) ⇒ Boolean = three2false
+  def scalaAnyThreeToThird[A, B, C]: (A, B, C) ⇒ C = three2third.asInstanceOf[(A, B, C) ⇒ C]
   def javaAnyToNone[A, B]: A ⇒ Option[B] = none
   def nullFun[T] = _nullFun.asInstanceOf[Any ⇒ T]
 
@@ -54,4 +55,6 @@ import akka.japi.{ Pair ⇒ JPair }
 
   private val three2false = (_: Any, _: Any, _: Any) ⇒ false
 
+  private val three2third = (_: Any, _: Any, third: Any) ⇒ third
+
 }
diff --git a/akka-cluster-sharding-typed/src/test/java/jdoc/akka/cluster/sharding/typed/ShardingCompileOnlyTest.java b/akka-cluster-sharding-typed/src/test/java/jdoc/akka/cluster/sharding/typed/ShardingCompileOnlyTest.java
index a96592e247..2cae52a2a4 100644
--- a/akka-cluster-sharding-typed/src/test/java/jdoc/akka/cluster/sharding/typed/ShardingCompileOnlyTest.java
+++ b/akka-cluster-sharding-typed/src/test/java/jdoc/akka/cluster/sharding/typed/ShardingCompileOnlyTest.java
@@ -36,7 +36,7 @@ public class ShardingCompileOnlyTest {
   }
 
   public static Behavior<CounterCommand> counter(String entityId, Integer value) {
-    return Behaviors.immutable(CounterCommand.class)
+    return Behaviors.receive(CounterCommand.class)
       .onMessage(Increment.class, (ctx, msg) -> {
         return counter(entityId,value + 1);
       })
diff --git a/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingPersistenceSpec.scala b/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingPersistenceSpec.scala
index 2a73996683..f2329de73e 100644
--- a/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingPersistenceSpec.scala
+++ b/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingPersistenceSpec.scala
@@ -45,7 +45,7 @@ object ClusterShardingPersistenceSpec {
   import PersistentBehaviors._
 
   def persistentActor(entityId: String): Behavior[Command] =
-    PersistentBehaviors.immutable[Command, String, String](
+    PersistentBehaviors.receive[Command, String, String](
       entityId,
       initialState = "",
       commandHandler = (_, state, cmd) ⇒ cmd match {
diff --git a/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingSpec.scala b/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingSpec.scala
index 2c015212a0..e14e65f5d1 100644
--- a/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingSpec.scala
+++ b/akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingSpec.scala
@@ -135,7 +135,7 @@ class ClusterShardingSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
   }
 
   private val typeKey = EntityTypeKey[TestProtocol]("envelope-shard")
-  private val behavior = Behaviors.immutable[TestProtocol] {
+  private val behavior = Behaviors.receive[TestProtocol] {
     case (_, StopPlz()) ⇒
       Behaviors.stopped
 
@@ -150,7 +150,7 @@ class ClusterShardingSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
   }
 
   private val typeKey2 = EntityTypeKey[IdTestProtocol]("no-envelope-shard")
-  private val behaviorWithId = Behaviors.immutable[IdTestProtocol] {
+  private val behaviorWithId = Behaviors.receive[IdTestProtocol] {
     case (_, IdStopPlz()) ⇒
       Behaviors.stopped
 
diff --git a/akka-cluster-sharding-typed/src/test/scala/doc/akka/cluster/sharding/typed/ShardingCompileOnlySpec.scala b/akka-cluster-sharding-typed/src/test/scala/doc/akka/cluster/sharding/typed/ShardingCompileOnlySpec.scala
index 8a2cefc18b..de2e170afe 100644
--- a/akka-cluster-sharding-typed/src/test/scala/doc/akka/cluster/sharding/typed/ShardingCompileOnlySpec.scala
+++ b/akka-cluster-sharding-typed/src/test/scala/doc/akka/cluster/sharding/typed/ShardingCompileOnlySpec.scala
@@ -30,7 +30,7 @@ object ShardingCompileOnlySpec {
   final case class GetValue(replyTo: ActorRef[Int]) extends CounterCommand
   case object GoodByeCounter extends CounterCommand
 
-  def counter(entityId: String, value: Int): Behavior[CounterCommand] = Behaviors.immutable[CounterCommand] {
+  def counter(entityId: String, value: Int): Behavior[CounterCommand] = Behaviors.receive[CounterCommand] {
     case (ctx, Increment) ⇒
       counter(entityId, value + 1)
     case (ctx, GetValue(replyTo)) ⇒
diff --git a/akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/internal/ReplicatorBehavior.scala b/akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/internal/ReplicatorBehavior.scala
index bfec589598..24ea440f2e 100644
--- a/akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/internal/ReplicatorBehavior.scala
+++ b/akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/internal/ReplicatorBehavior.scala
@@ -59,7 +59,7 @@ import akka.actor.typed.Terminated
           }
         }
 
-        Behaviors.immutable[SReplicator.Command] { (ctx, msg) ⇒
+        Behaviors.receive[SReplicator.Command] { (ctx, msg) ⇒
           msg match {
             case cmd: SReplicator.Get[_] ⇒
               untypedReplicator.tell(
@@ -184,7 +184,7 @@ import akka.actor.typed.Terminated
 
           }
         }
-          .onSignal {
+          .receiveSignal {
             case (ctx, Terminated(ref: ActorRef[JReplicator.Changed[ReplicatedData]] @unchecked)) ⇒
               stopSubscribeAdapter(ref)
           }
diff --git a/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/AdaptedClusterImpl.scala b/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/AdaptedClusterImpl.scala
index eb1b4c7bc0..a4ce329e4d 100644
--- a/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/AdaptedClusterImpl.scala
+++ b/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/AdaptedClusterImpl.scala
@@ -52,7 +52,7 @@ private[akka] object AdapterClusterImpl {
       }
     }
 
-    Behaviors.immutable[AnyRef] { (ctx, msg) ⇒
+    Behaviors.receive[AnyRef] { (ctx, msg) ⇒
 
       msg match {
         case Subscribe(subscriber: ActorRef[SelfUp] @unchecked, clazz) if clazz == classOf[SelfUp] ⇒
@@ -94,7 +94,7 @@ private[akka] object AdapterClusterImpl {
           Behaviors.same
 
       }
-    }.onSignal {
+    }.receiveSignal {
 
       case (_, Terminated(ref)) ⇒
         upSubscribers = upSubscribers.filterNot(_ == ref)
@@ -104,7 +104,7 @@ private[akka] object AdapterClusterImpl {
     }.narrow[ClusterStateSubscription]
   }
 
-  private def managerBehavior(adaptedCluster: akka.cluster.Cluster) = Behaviors.immutable[ClusterCommand]((ctx, msg) ⇒
+  private def managerBehavior(adaptedCluster: akka.cluster.Cluster) = Behaviors.receive[ClusterCommand]((ctx, msg) ⇒
     msg match {
       case Join(address) ⇒
         adaptedCluster.join(address)
diff --git a/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionist.scala b/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionist.scala
index f4bba1bef8..fec22d115d 100644
--- a/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionist.scala
+++ b/akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionist.scala
@@ -136,8 +136,8 @@ private[typed] object ClusterReceptionist extends ReceptionistBehaviorProvider {
       def watchWith(ctx: ActorContext[Any], target: ActorRef[_], msg: InternalCommand): Unit =
         ctx.spawnAnonymous[Nothing](Behaviors.setup[Nothing] { innerCtx ⇒
           innerCtx.watch(target)
-          Behaviors.immutable[Nothing]((_, _) ⇒ Behaviors.same)
-            .onSignal {
+          Behaviors.receive[Nothing]((_, _) ⇒ Behaviors.same)
+            .receiveSignal {
               case (_, Terminated(`target`)) ⇒
                 ctx.self ! msg
                 Behaviors.stopped
@@ -263,7 +263,7 @@ private[typed] object ClusterReceptionist extends ReceptionistBehaviorProvider {
             Behavior.same
       }
 
-      Behaviors.immutable[Any] { (ctx, msg) ⇒
+      Behaviors.receive[Any] { (ctx, msg) ⇒
         msg match {
           // support two heterogenous types of messages without union types
           case cmd: Command         ⇒ onCommand(cmd)
diff --git a/akka-cluster-typed/src/test/java/akka/cluster/ddata/typed/javadsl/ReplicatorTest.java b/akka-cluster-typed/src/test/java/akka/cluster/ddata/typed/javadsl/ReplicatorTest.java
index cb4dafb21f..ab59c5119e 100644
--- a/akka-cluster-typed/src/test/java/akka/cluster/ddata/typed/javadsl/ReplicatorTest.java
+++ b/akka-cluster-typed/src/test/java/akka/cluster/ddata/typed/javadsl/ReplicatorTest.java
@@ -26,7 +26,7 @@ import akka.actor.typed.Behavior;
 import akka.cluster.ddata.typed.javadsl.Replicator.Command;
 import akka.actor.typed.javadsl.Behaviors;
 import akka.actor.typed.javadsl.Adapter;
-import akka.actor.typed.javadsl.Behaviors.MutableBehavior;
+import akka.actor.typed.javadsl.MutableBehavior;
 import akka.actor.typed.javadsl.ActorContext;
 
 public class ReplicatorTest extends JUnitSuite {
@@ -111,7 +111,7 @@ public class ReplicatorTest extends JUnitSuite {
     }
 
     public static Behavior<ClientCommand> create(ActorRef<Command> replicator, Cluster node) {
-      return Behaviors.mutable(ctx -> new Client(replicator, node, ctx));
+      return Behaviors.setup(ctx -> new Client(replicator, node, ctx));
     }
 
     @Override
diff --git a/akka-cluster-typed/src/test/java/jdocs/akka/cluster/typed/ReceptionistExampleTest.java b/akka-cluster-typed/src/test/java/jdocs/akka/cluster/typed/ReceptionistExampleTest.java
index 1388e8fe33..8e6f82510b 100644
--- a/akka-cluster-typed/src/test/java/jdocs/akka/cluster/typed/ReceptionistExampleTest.java
+++ b/akka-cluster-typed/src/test/java/jdocs/akka/cluster/typed/ReceptionistExampleTest.java
@@ -10,6 +10,7 @@ import akka.actor.typed.ActorSystem;
 import akka.actor.typed.Behavior;
 import akka.actor.typed.javadsl.ActorContext;
 import akka.actor.typed.javadsl.Behaviors;
+import akka.actor.typed.javadsl.MutableBehavior;
 import akka.actor.typed.receptionist.Receptionist;
 import akka.actor.typed.receptionist.ServiceKey;
 import akka.cluster.ClusterEvent;
@@ -31,7 +32,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
 
   static class RandomRouter {
 
-    private static class RouterBehavior<T> extends Behaviors.MutableBehavior<Object> {
+    private static class RouterBehavior<T> extends MutableBehavior<Object> {
       private final Class<T> messageClass;
       private final ServiceKey<T> serviceKey;
       private final List<ActorRef<T>> routees = new ArrayList<>();
@@ -58,7 +59,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
     }
 
     public static <T> Behavior<T> router(ServiceKey<T> serviceKey, Class<T> messageClass) {
-      return Behaviors.mutable(ctx -> new RouterBehavior<T>(ctx, messageClass, serviceKey)).narrow();
+      return Behaviors.setup(ctx -> new RouterBehavior<T>(ctx, messageClass, serviceKey)).narrow();
     }
   }
 
@@ -73,7 +74,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
       }
     }
 
-    private static class ClusterRouterBehavior<T> extends Behaviors.MutableBehavior<Object> {
+    private static class ClusterRouterBehavior<T> extends MutableBehavior<Object> {
       private final Class<T> messageClass;
       private final ServiceKey<T> serviceKey;
       private final List<ActorRef<T>> routees = new ArrayList<>();
@@ -133,7 +134,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
     }
 
     public static <T> Behavior<T> clusterRouter(ServiceKey<T> serviceKey, Class<T> messageClass) {
-      return Behaviors.mutable((ctx) -> new ClusterRouterBehavior<T>(ctx, messageClass, serviceKey)).narrow();
+      return Behaviors.setup((ctx) -> new ClusterRouterBehavior<T>(ctx, messageClass, serviceKey)).narrow();
     }
   }
 
@@ -155,7 +156,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
       return Behaviors.setup((ctx) -> {
         ctx.getSystem().receptionist()
           .tell(Receptionist.register(PingServiceKey, ctx.getSelf()));
-        return Behaviors.immutable(Ping.class)
+        return Behaviors.receive(Ping.class)
           .onMessage(Ping.class, (c, msg) -> {
             msg.replyTo.tell(new Pong());
             return Behaviors.same();
@@ -168,7 +169,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
     static Behavior<Pong> pinger(ActorRef<Ping> pingService) {
       return Behaviors.setup((ctx) -> {
         pingService.tell(new Ping(ctx.getSelf()));
-        return Behaviors.immutable(Pong.class)
+        return Behaviors.receive(Pong.class)
           .onMessage(Pong.class, (c, msg) -> {
             System.out.println("I was ponged! " + msg);
             return Behaviors.same();
@@ -184,7 +185,7 @@ public class ReceptionistExampleTest extends JUnitSuite {
           .tell(Receptionist.subscribe(PingServiceKey, ctx.getSelf().narrow()));
         ActorRef<Ping> ps = ctx.spawnAnonymous(pingService());
         ctx.watch(ps);
-        return Behaviors.immutable(Object.class)
+        return Behaviors.receive(Object.class)
           .onMessage(Receptionist.Listing.class, listing -> listing.isForKey(PingServiceKey), (c, msg) -> {
           msg.getServiceInstances(PingServiceKey).forEach(ar -> ctx.spawnAnonymous(pinger(ar)));
           return Behaviors.same();
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/ddata/typed/scaladsl/ReplicatorSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/ddata/typed/scaladsl/ReplicatorSpec.scala
index 01f8e1f5fc..4cca8197a0 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/ddata/typed/scaladsl/ReplicatorSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/ddata/typed/scaladsl/ReplicatorSpec.scala
@@ -58,7 +58,7 @@ object ReplicatorSpec {
       replicator ! Replicator.Subscribe(Key, changedAdapter)
 
       def behavior(cachedValue: Int): Behavior[ClientCommand] = {
-        Behaviors.immutable[ClientCommand] { (ctx, msg) ⇒
+        Behaviors.receive[ClientCommand] { (ctx, msg) ⇒
           msg match {
             case Increment ⇒
               replicator ! Replicator.Update(Key, GCounter.empty, Replicator.WriteLocal, updateResponseAdapter)(_ + 1)
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ActorSystemSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ActorSystemSpec.scala
index b6186858aa..fdc1a49c88 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ActorSystemSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ActorSystemSpec.scala
@@ -45,7 +45,7 @@ class ActorSystemSpec extends WordSpec with Matchers with BeforeAndAfterAll
     "start the guardian actor and terminate when it terminates" in {
       val t = withSystem(
         "a",
-        Behaviors.immutable[Probe] { case (_, p) ⇒ p.replyTo ! p.msg; Behaviors.stopped }, doTerminate = false) { sys ⇒
+        Behaviors.receive[Probe] { case (_, p) ⇒ p.replyTo ! p.msg; Behaviors.stopped }, doTerminate = false) { sys ⇒
           val inbox = TestInbox[String]("a")
           sys ! Probe("hello", inbox.ref)
           eventually {
@@ -69,9 +69,9 @@ class ActorSystemSpec extends WordSpec with Matchers with BeforeAndAfterAll
     "terminate the guardian actor" in {
       val inbox = TestInbox[String]("terminate")
       val sys = system(
-        Behaviors.immutable[Probe] {
+        Behaviors.receive[Probe] {
           case (_, _) ⇒ Behaviors.unhandled
-        } onSignal {
+        } receiveSignal {
           case (_, PostStop) ⇒
             inbox.ref ! "done"
             Behaviors.same
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonApiSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonApiSpec.scala
index 8124e61db9..c3895c3270 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonApiSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonApiSpec.scala
@@ -48,7 +48,7 @@ object ClusterSingletonApiSpec {
 
   case object Perish extends PingProtocol
 
-  val pingPong = Behaviors.immutable[PingProtocol] { (_, msg) ⇒
+  val pingPong = Behaviors.receive[PingProtocol] { (_, msg) ⇒
 
     msg match {
       case Ping(respondTo) ⇒
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonPersistenceSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonPersistenceSpec.scala
index 3187d461c7..e94cb819d0 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonPersistenceSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/ClusterSingletonPersistenceSpec.scala
@@ -35,7 +35,7 @@ object ClusterSingletonPersistenceSpec {
   private final case object StopPlz extends Command
 
   val persistentActor: Behavior[Command] =
-    PersistentBehaviors.immutable[Command, String, String](
+    PersistentBehaviors.receive[Command, String, String](
       persistenceId = "TheSingleton",
       initialState = "",
       commandHandler = (_, state, cmd) ⇒ cmd match {
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteContextAskSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteContextAskSpec.scala
index 3743b1eac5..2d3e9b9c9e 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteContextAskSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteContextAskSpec.scala
@@ -71,7 +71,7 @@ object RemoteContextAskSpec {
   case object Pong
   case class Ping(respondTo: ActorRef[Pong.type])
 
-  def pingPong = Behaviors.immutable[Ping] { (_, msg) ⇒
+  def pingPong = Behaviors.receive[Ping] { (_, msg) ⇒
     msg match {
       case Ping(sender) ⇒
         sender ! Pong
@@ -118,7 +118,7 @@ class RemoteContextAskSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
           case Failure(ex)   ⇒ ex
         }
 
-        Behaviors.immutable { (_, msg) ⇒
+        Behaviors.receive { (_, msg) ⇒
           node1Probe.ref ! msg
           Behaviors.same
         }
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteDeployNotAllowedSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteDeployNotAllowedSpec.scala
index b4a037a948..3224a17f59 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteDeployNotAllowedSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteDeployNotAllowedSpec.scala
@@ -58,7 +58,7 @@ class RemoteDeployNotAllowedSpec extends ActorTestKit with TypedAkkaSpecWithShut
       case class SpawnChild(name: String) extends GuardianProtocol
       case object SpawnAnonymous extends GuardianProtocol
 
-      val guardianBehavior = Behaviors.immutable[GuardianProtocol] { (ctx, msg) ⇒
+      val guardianBehavior = Behaviors.receive[GuardianProtocol] { (ctx, msg) ⇒
 
         msg match {
           case SpawnChild(name) ⇒
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteMessageSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteMessageSpec.scala
index fdb9f483ad..da93578144 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteMessageSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteMessageSpec.scala
@@ -71,7 +71,7 @@ class RemoteMessageSpec extends AkkaSpec(RemoteMessageSpec.config) {
     "something something" in {
 
       val pingPromise = Promise[Done]()
-      val ponger = Behaviors.immutable[Ping]((_, msg) ⇒
+      val ponger = Behaviors.receive[Ping]((_, msg) ⇒
         msg match {
           case Ping(sender) ⇒
             pingPromise.success(Done)
@@ -92,7 +92,7 @@ class RemoteMessageSpec extends AkkaSpec(RemoteMessageSpec.config) {
           ActorRefResolver(typedSystem2).resolveActorRef[Ping](remoteRefStr)
 
         val pongPromise = Promise[Done]()
-        val recipient = system2.spawn(Behaviors.immutable[String] { (_, _) ⇒
+        val recipient = system2.spawn(Behaviors.receive[String] { (_, _) ⇒
           pongPromise.success(Done)
           Behaviors.stopped
         }, "recipient")
diff --git a/akka-cluster-typed/src/test/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionistSpec.scala b/akka-cluster-typed/src/test/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionistSpec.scala
index 83520c200a..dbfbfe0189 100644
--- a/akka-cluster-typed/src/test/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionistSpec.scala
+++ b/akka-cluster-typed/src/test/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionistSpec.scala
@@ -56,7 +56,7 @@ object ClusterReceptionistSpec {
   case class Ping(respondTo: ActorRef[Pong.type]) extends PingProtocol
   case object Perish extends PingProtocol
 
-  val pingPongBehavior = Behaviors.immutable[PingProtocol] { (_, msg) ⇒
+  val pingPongBehavior = Behaviors.receive[PingProtocol] { (_, msg) ⇒
     msg match {
       case Ping(respondTo) ⇒
         respondTo ! Pong
diff --git a/akka-cluster-typed/src/test/scala/docs/akka/cluster/typed/ReceptionistExampleSpec.scala b/akka-cluster-typed/src/test/scala/docs/akka/cluster/typed/ReceptionistExampleSpec.scala
index 83134c2e97..3184dd4db1 100644
--- a/akka-cluster-typed/src/test/scala/docs/akka/cluster/typed/ReceptionistExampleSpec.scala
+++ b/akka-cluster-typed/src/test/scala/docs/akka/cluster/typed/ReceptionistExampleSpec.scala
@@ -27,7 +27,7 @@ object RandomRouter {
       ctx.system.receptionist ! Receptionist.Subscribe(serviceKey, ctx.self)
 
       def routingBehavior(routees: Vector[ActorRef[T]]): Behavior[Any] =
-        Behaviors.immutable { (_, msg) ⇒
+        Behaviors.receive { (_, msg) ⇒
           msg match {
             case serviceKey.Listing(services) ⇒
               routingBehavior(services.toVector)
@@ -60,7 +60,7 @@ object RandomRouter {
       cluster.subscriptions ! Subscribe(reachabilityAdapter, classOf[ReachabilityEvent])
 
       def routingBehavior(routees: Vector[ActorRef[T]], unreachable: Set[Address]): Behavior[Any] =
-        Behaviors.immutable { (_, msg) ⇒
+        Behaviors.receive { (_, msg) ⇒
           msg match {
             case serviceKey.Listing(services: Set[ActorRef[T]]) ⇒
               routingBehavior(services.toVector, unreachable)
@@ -100,7 +100,7 @@ object PingPongExample {
   val pingService: Behavior[Ping] =
     Behaviors.setup { ctx ⇒
       ctx.system.receptionist ! Receptionist.Register(PingServiceKey, ctx.self)
-      Behaviors.immutable[Ping] { (_, msg) ⇒
+      Behaviors.receive[Ping] { (_, msg) ⇒
         msg match {
           case Ping(replyTo) ⇒
             replyTo ! Pong
@@ -113,7 +113,7 @@ object PingPongExample {
   //#pinger
   def pinger(pingService: ActorRef[Ping]) = Behaviors.setup[Pong.type] { ctx ⇒
     pingService ! Ping(ctx.self)
-    Behaviors.immutable { (_, msg) ⇒
+    Behaviors.receive { (_, msg) ⇒
       println("I was ponged!!" + msg)
       Behaviors.same
     }
@@ -125,11 +125,11 @@ object PingPongExample {
     ctx.system.receptionist ! Receptionist.Subscribe(PingServiceKey, ctx.self)
     val ps = ctx.spawnAnonymous(pingService)
     ctx.watch(ps)
-    Behaviors.immutablePartial[Listing] {
-      case (_, PingServiceKey.Listing(listings)) if listings.nonEmpty ⇒
+    Behaviors.receiveMessagePartial[Listing] {
+      case PingServiceKey.Listing(listings) if listings.nonEmpty ⇒
         listings.foreach(ps ⇒ ctx.spawnAnonymous(pinger(ps)))
         Behaviors.same
-    } onSignal {
+    } receiveSignal {
       case (_, Terminated(`ps`)) ⇒
         println("Ping service has shut down")
         Behaviors.stopped
@@ -141,11 +141,11 @@ object PingPongExample {
   val guardianJustPingService: Behavior[Nothing] = Behaviors.setup[Listing] { ctx ⇒
     val ps = ctx.spawnAnonymous(pingService)
     ctx.watch(ps)
-    Behaviors.immutablePartial[Listing] {
-      case (c, PingServiceKey.Listing(listings)) if listings.nonEmpty ⇒
+    Behaviors.receiveMessagePartial[Listing] {
+      case PingServiceKey.Listing(listings) if listings.nonEmpty ⇒
         listings.foreach(ps ⇒ ctx.spawnAnonymous(pinger(ps)))
         Behaviors.same
-    } onSignal {
+    } receiveSignal {
       case (_, Terminated(`ps`)) ⇒
         println("Ping service has shut down")
         Behaviors.stopped
@@ -156,8 +156,8 @@ object PingPongExample {
   //#pinger-guardian-just-pinger
   val guardianJustPinger: Behavior[Nothing] = Behaviors.setup[Listing] { ctx ⇒
     ctx.system.receptionist ! Receptionist.Subscribe(PingServiceKey, ctx.self)
-    Behaviors.immutablePartial[Listing] {
-      case (c, PingServiceKey.Listing(listings)) if listings.nonEmpty ⇒
+    Behaviors.receiveMessagePartial[Listing] {
+      case PingServiceKey.Listing(listings) if listings.nonEmpty ⇒
         listings.foreach(ps ⇒ ctx.spawnAnonymous(pinger(ps)))
         Behaviors.same
     }
diff --git a/akka-docs/src/main/paradox/typed/actors.md b/akka-docs/src/main/paradox/typed/actors.md
index dc5fed093c..4776033532 100644
--- a/akka-docs/src/main/paradox/typed/actors.md
+++ b/akka-docs/src/main/paradox/typed/actors.md
@@ -50,12 +50,11 @@ supplies so that the `HelloWorld` Actor can send back the confirmation
 message.
 
 The behavior of the Actor is defined as the `greeter` value with the help
-of the `immutable` behavior constructor. This constructor is called
-immutable because the behavior instance doesn't have or close over any mutable
-state. Processing the next message may result in a new behavior that can
-potentially be different from this one. State is updated by returning a new
-behavior that holds the new immutable state. In this case we don't need to
-update any state, so we return `Same`.
+of the `receive` behavior factory. Processing the next message then results
+in a new behavior that can potentially be different from this one. State is 
+updated by returning a new behavior that holds the new immutable state. In this 
+case we don't need to update any state, so we return `Same`, which means 
+the next behavior is "the same as the current one".
 
 The type of the messages handled by this behavior is declared to be of class
 `Greet`, meaning that `msg` argument is
@@ -248,14 +247,14 @@ Actor will perform its job on its own accord, we do not need to send messages
 from the outside, so we declare it to be of type @scala[`NotUsed`]@java[`Void`]. Actors receive not
 only external messages, they also are notified of certain system events,
 so-called Signals. In order to get access to those we choose to implement this
-particular one using the `immutable` behavior decorator. The
+particular one using the `receive` behavior decorator. The
 provided `onSignal` function will be invoked for signals (subclasses of `Signal`)
 or the `onMessage` function for user messages.
 
-This particular `main` Actor is created using `Behaviors.onStart`, which is like a factory for a behavior.
-Creation of the behavior instance is deferred until the actor is started, as opposed to `Behaviors.immutable`
+This particular `main` Actor is created using `Behaviors.setup`, which is like a factory for a behavior.
+Creation of the behavior instance is deferred until the actor is started, as opposed to `Behaviors.receive`
 that creates the behavior instance immediately before the actor is running. The factory function in
-`onStart` is passed the `ActorContext` as parameter and that can for example be used for spawning child actors.
+`setup` is passed the `ActorContext` as parameter and that can for example be used for spawning child actors.
 This `main` Actor creates the chat room and the gabbler and the session between them is initiated, and when the
 gabbler is finished we will receive the `Terminated` event due to having
 called `ctx.watch` for it. This allows us to shut down the Actor system: when
diff --git a/akka-docs/src/main/paradox/typed/interaction-patterns.md b/akka-docs/src/main/paradox/typed/interaction-patterns.md
index 4d77b512e9..27ae60f88b 100644
--- a/akka-docs/src/main/paradox/typed/interaction-patterns.md
+++ b/akka-docs/src/main/paradox/typed/interaction-patterns.md
@@ -224,7 +224,8 @@ Java
 
 There are a few things worth noting here:
 
-* To get access to the timers you start with `Behaviors.withTimers` that will pass a `TimerScheduler` instance to the function. This can be used with any type of `Behavior`, such as `immutable` or `mutable`.
+* To get access to the timers you start with `Behaviors.withTimers` that will pass a `TimerScheduler` instance to the function. 
+This can be used with any type of `Behavior`, including `receive`, `receiveMessage`, but also `setup` or any other behavior.
 * Each timer has a key and if a new timer with same key is started the previous is cancelled and it's guaranteed that a message from the previous timer is not received, even though it might already be enqueued in the mailbox when the new timer is started.
 * Both periodic and single message timers are supported. 
 * The `TimerScheduler` is mutable in itself, because it performs and manages the side effects of registering the scheduled tasks.
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingEvents.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingEvents.scala
index ee6973d603..cd7758fc0a 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingEvents.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingEvents.scala
@@ -68,13 +68,13 @@ private[persistence] class EventsourcedReplayingEvents[C, E, S](override val set
 
   private def stay(state: ReplayingState[S]): Behavior[InternalProtocol] =
     withMdc(setup, MDC.ReplayingEvents) {
-      Behaviors.immutable[InternalProtocol] {
-        case (_, JournalResponse(r))      ⇒ onJournalResponse(state, r)
-        case (_, SnapshotterResponse(r))  ⇒ onSnapshotterResponse(r)
-        case (_, RecoveryTickEvent(snap)) ⇒ onRecoveryTick(state, snap)
-        case (_, cmd: IncomingCommand[C]) ⇒ onCommand(cmd)
-        case (_, RecoveryPermitGranted)   ⇒ Behaviors.unhandled // should not happen, we already have the permit
-      }.onSignal(returnPermitOnStop)
+      Behaviors.receiveMessage[InternalProtocol] {
+        case JournalResponse(r)      ⇒ onJournalResponse(state, r)
+        case SnapshotterResponse(r)  ⇒ onSnapshotterResponse(r)
+        case RecoveryTickEvent(snap) ⇒ onRecoveryTick(state, snap)
+        case cmd: IncomingCommand[C] ⇒ onCommand(cmd)
+        case RecoveryPermitGranted   ⇒ Behaviors.unhandled // should not happen, we already have the permit
+      }.receiveSignal(returnPermitOnStop)
     }
 
   private def onJournalResponse(
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingSnapshot.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingSnapshot.scala
index ea94c83a0e..c87bcb00c5 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingSnapshot.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingSnapshot.scala
@@ -46,13 +46,13 @@ private[akka] class EventsourcedReplayingSnapshot[C, E, S](override val setup: E
     loadSnapshot(setup.recovery.fromSnapshot, setup.recovery.toSequenceNr)
 
     withMdc(setup, MDC.ReplayingSnapshot) {
-      Behaviors.immutable[InternalProtocol] {
-        case (_, SnapshotterResponse(r))      ⇒ onSnapshotterResponse(r)
-        case (_, JournalResponse(r))          ⇒ onJournalResponse(r)
-        case (_, RecoveryTickEvent(snapshot)) ⇒ onRecoveryTick(snapshot)
-        case (_, cmd: IncomingCommand[C])     ⇒ onCommand(cmd)
-        case (_, RecoveryPermitGranted)       ⇒ Behaviors.unhandled // should not happen, we already have the permit
-      }.onSignal(returnPermitOnStop)
+      Behaviors.receiveMessage[InternalProtocol] {
+        case SnapshotterResponse(r)      ⇒ onSnapshotterResponse(r)
+        case JournalResponse(r)          ⇒ onJournalResponse(r)
+        case RecoveryTickEvent(snapshot) ⇒ onRecoveryTick(snapshot)
+        case cmd: IncomingCommand[C]     ⇒ onCommand(cmd)
+        case RecoveryPermitGranted       ⇒ Behaviors.unhandled // should not happen, we already have the permit
+      }.receiveSignal(returnPermitOnStop)
     }
   }
 
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRequestingRecoveryPermit.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRequestingRecoveryPermit.scala
index 61781458ed..c74a5b067b 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRequestingRecoveryPermit.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRequestingRecoveryPermit.scala
@@ -37,7 +37,7 @@ private[akka] class EventsourcedRequestingRecoveryPermit[C, E, S](override val s
     requestRecoveryPermit()
 
     withMdc {
-      Behaviors.immutable[InternalProtocol] {
+      Behaviors.receive[InternalProtocol] {
         case (_, InternalProtocol.RecoveryPermitGranted) ⇒
           becomeReplaying()
 
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRunning.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRunning.scala
index e6d6b8db6d..b689d9d4f4 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRunning.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRunning.scala
@@ -7,7 +7,7 @@ package akka.persistence.typed.internal
 import akka.actor.typed.{ Behavior, Signal }
 import akka.actor.typed.Behavior.StoppedBehavior
 import akka.actor.typed.scaladsl.Behaviors
-import akka.actor.typed.scaladsl.Behaviors.MutableBehavior
+import akka.actor.typed.scaladsl.MutableBehavior
 import akka.annotation.InternalApi
 import akka.persistence.JournalProtocol._
 import akka.persistence._
@@ -148,9 +148,9 @@ private[akka] object EventsourcedRunning {
     }
 
     withMdc(setup, MDC.RunningCmds) {
-      Behaviors.immutable[EventsourcedBehavior.InternalProtocol] {
-        case (_, IncomingCommand(c: C @unchecked)) ⇒ onCommand(state, c)
-        case _                                     ⇒ Behaviors.unhandled
+      Behaviors.receiveMessage[EventsourcedBehavior.InternalProtocol] {
+        case IncomingCommand(c: C @unchecked) ⇒ onCommand(state, c)
+        case _                                ⇒ Behaviors.unhandled
       }
     }
 
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/javadsl/PersistentBehavior.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/javadsl/PersistentBehavior.scala
index f743646e40..7325e18003 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/javadsl/PersistentBehavior.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/javadsl/PersistentBehavior.scala
@@ -92,7 +92,7 @@ abstract class PersistentBehavior[Command, Event, State >: Null](val persistence
 
   /** INTERNAL API */
   @InternalApi private[akka] override def untypedProps(props: akka.actor.typed.Props): akka.actor.Props = {
-    val behaviorImpl = scaladsl.PersistentBehaviors.immutable[Command, Event, State](
+    val behaviorImpl = scaladsl.PersistentBehaviors.receive[Command, Event, State](
       persistenceId,
       initialState,
       (c, state, cmd) ⇒ commandHandler()(c.asJava, state, cmd).asInstanceOf[EffectImpl[Event, State]],
diff --git a/akka-persistence-typed/src/main/scala/akka/persistence/typed/scaladsl/PersistentBehaviors.scala b/akka-persistence-typed/src/main/scala/akka/persistence/typed/scaladsl/PersistentBehaviors.scala
index 6ec2ac5470..9258173691 100644
--- a/akka-persistence-typed/src/main/scala/akka/persistence/typed/scaladsl/PersistentBehaviors.scala
+++ b/akka-persistence-typed/src/main/scala/akka/persistence/typed/scaladsl/PersistentBehaviors.scala
@@ -18,7 +18,7 @@ object PersistentBehaviors {
   /**
    * Create a `Behavior` for a persistent actor.
    */
-  def immutable[Command, Event, State](
+  def receive[Command, Event, State](
     persistenceId:  String,
     initialState:   State,
     commandHandler: CommandHandler[Command, Event, State],
diff --git a/akka-persistence-typed/src/test/java/akka/persistence/typed/javadsl/PersistentActorTest.java b/akka-persistence-typed/src/test/java/akka/persistence/typed/javadsl/PersistentActorTest.java
index da847415e0..f9677dac97 100644
--- a/akka-persistence-typed/src/test/java/akka/persistence/typed/javadsl/PersistentActorTest.java
+++ b/akka-persistence-typed/src/test/java/akka/persistence/typed/javadsl/PersistentActorTest.java
@@ -8,11 +8,8 @@ import akka.actor.typed.ActorRef;
 import akka.actor.typed.javadsl.Behaviors;
 import akka.japi.Pair;
 import akka.japi.function.Function3;
-import akka.persistence.typed.scaladsl.PersistentBehaviorSpec;
 import akka.persistence.typed.scaladsl.PersistentBehaviorSpec$;
-import akka.testkit.AkkaJUnitActorSystemResource;
 import akka.testkit.typed.javadsl.TestKitJunitResource;
-import akka.testkit.typed.scaladsl.ActorTestKit;
 import akka.testkit.typed.javadsl.TestProbe;
 import org.junit.ClassRule;
 import org.junit.Test;
@@ -204,7 +201,7 @@ public class PersistentActorTest {
           .matchCommand(IncrementLater.class, (ctx, state, command) -> {
             ActorRef<Object> delay = ctx.spawnAnonymous(Behaviors.withTimers(timers -> {
               timers.startSingleTimer(Tick.instance, Tick.instance, FiniteDuration.create(10, TimeUnit.MILLISECONDS));
-              return Behaviors.immutable((context, o) -> Behaviors.stopped());
+              return Behaviors.receive((context, o) -> Behaviors.stopped());
             }));
             ctx.watchWith(delay, new DelayFinished());
             return Effect().none();
diff --git a/akka-persistence-typed/src/test/scala/akka/persistence/typed/internal/RecoveryPermitterSpec.scala b/akka-persistence-typed/src/test/scala/akka/persistence/typed/internal/RecoveryPermitterSpec.scala
index 72e68b9df2..7df4567cb1 100644
--- a/akka-persistence-typed/src/test/scala/akka/persistence/typed/internal/RecoveryPermitterSpec.scala
+++ b/akka-persistence-typed/src/test/scala/akka/persistence/typed/internal/RecoveryPermitterSpec.scala
@@ -42,7 +42,7 @@ object RecoveryPermitterSpec {
     commandProbe:    TestProbe[Any],
     eventProbe:      TestProbe[Any],
     throwOnRecovery: Boolean        = false): Behavior[Command] =
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = name,
       initialState = EmptyState,
       commandHandler = CommandHandler.command {
@@ -57,7 +57,7 @@ object RecoveryPermitterSpec {
       }
 
   def forwardingBehavior(target: TestProbe[Any]): Behavior[Any] =
-    Behaviors.immutable[Any] {
+    Behaviors.receive[Any] {
       (_, any) ⇒ target.ref ! any; Behaviors.same
     }
 }
@@ -188,7 +188,7 @@ class RecoveryPermitterSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
           val persistentActor =
             ctx.spawnAnonymous(persistentBehavior("p3", p3, p3, throwOnRecovery = true))
           ctx.watch(persistentActor)
-          Behaviors.immutable[Command] {
+          Behaviors.receive[Command] {
             case (_, StopActor) ⇒
               stopProbe.ref ! persistentActor
               ctx.stop(persistentActor)
diff --git a/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentActorCompileOnlyTest.scala b/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentActorCompileOnlyTest.scala
index 6a1a90a6b4..48ec8a05ec 100644
--- a/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentActorCompileOnlyTest.scala
+++ b/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentActorCompileOnlyTest.scala
@@ -43,7 +43,7 @@ object PersistentActorCompileOnlyTest {
 
     //#behavior
     val simpleBehavior: PersistentBehavior[SimpleCommand, SimpleEvent, ExampleState] =
-      PersistentBehaviors.immutable[SimpleCommand, SimpleEvent, ExampleState](
+      PersistentBehaviors.receive[SimpleCommand, SimpleEvent, ExampleState](
         persistenceId = "sample-id-1",
         initialState = ExampleState(Nil),
         commandHandler = commandHandler,
@@ -63,7 +63,7 @@ object PersistentActorCompileOnlyTest {
 
     case class ExampleState(events: List[String] = Nil)
 
-    PersistentBehaviors.immutable[MyCommand, MyEvent, ExampleState](
+    PersistentBehaviors.receive[MyCommand, MyEvent, ExampleState](
       persistenceId = "sample-id-1",
 
       initialState = ExampleState(Nil),
@@ -107,7 +107,7 @@ object PersistentActorCompileOnlyTest {
         .foreach(sender ! _)
     }
 
-    PersistentBehaviors.immutable[Command, Event, EventsInFlight](
+    PersistentBehaviors.receive[Command, Event, EventsInFlight](
       persistenceId = "recovery-complete-id",
 
       initialState = EventsInFlight(0, Map.empty),
@@ -149,7 +149,7 @@ object PersistentActorCompileOnlyTest {
     sealed trait Event
     case class MoodChanged(to: Mood) extends Event
 
-    val b: Behavior[Command] = PersistentBehaviors.immutable[Command, Event, Mood](
+    val b: Behavior[Command] = PersistentBehaviors.receive[Command, Event, Mood](
       persistenceId = "myPersistenceId",
       initialState = Happy,
       commandHandler = CommandHandler.byState {
@@ -190,7 +190,7 @@ object PersistentActorCompileOnlyTest {
 
     case class State(tasksInFlight: List[Task])
 
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "asdf",
       initialState = State(Nil),
       commandHandler = CommandHandler.command {
@@ -217,7 +217,7 @@ object PersistentActorCompileOnlyTest {
 
     def worker(task: Task): Behavior[Nothing] = ???
 
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "asdf",
       initialState = State(Nil),
       commandHandler = (ctx, _, cmd) ⇒ cmd match {
@@ -280,7 +280,7 @@ object PersistentActorCompileOnlyTest {
           .persist[Event, List[Id]](ItemAdded(id))
           .andThen(metadataRegistry ! GetMetaData(id, adapt))
 
-      PersistentBehaviors.immutable[Command, Event, List[Id]](
+      PersistentBehaviors.receive[Command, Event, List[Id]](
         persistenceId = "basket-1",
         initialState = Nil,
         commandHandler =
@@ -341,7 +341,7 @@ object PersistentActorCompileOnlyTest {
       if (currentState == newMood) Effect.none
       else Effect.persist(MoodChanged(newMood))
 
-    PersistentBehaviors.immutable[Command, Event, Mood](
+    PersistentBehaviors.receive[Command, Event, Mood](
       persistenceId = "myPersistenceId",
       initialState = Sad,
       commandHandler = (_, state, cmd) ⇒
@@ -377,7 +377,7 @@ object PersistentActorCompileOnlyTest {
 
     class State
 
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "myPersistenceId",
       initialState = new State,
       commandHandler = CommandHandler.command {
diff --git a/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentBehaviorSpec.scala b/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentBehaviorSpec.scala
index 896eade33d..a8e4fa54ff 100644
--- a/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentBehaviorSpec.scala
+++ b/akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentBehaviorSpec.scala
@@ -84,7 +84,7 @@ object PersistentBehaviorSpec {
     persistenceId: String,
     loggingActor:  ActorRef[String],
     probe:         ActorRef[(State, Event)]): PersistentBehavior[Command, Event, State] = {
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId,
       initialState = State(0, Vector.empty),
       commandHandler = (ctx, state, cmd) ⇒ cmd match {
@@ -116,7 +116,7 @@ object PersistentBehaviorSpec {
           // purpose is to test signals
           val delay = ctx.spawnAnonymous(Behaviors.withTimers[Tick.type] { timers ⇒
             timers.startSingleTimer(Tick, Tick, 10.millis)
-            Behaviors.immutable((_, msg) ⇒ msg match {
+            Behaviors.receive((_, msg) ⇒ msg match {
               case Tick ⇒ Behaviors.stopped
             })
           })
@@ -412,8 +412,8 @@ class PersistentBehaviorSpec extends ActorTestKit with TypedAkkaSpecWithShutdown
       val probe = TestProbe[String]()
       val w = Behaviors.setup[Any] { (ctx) ⇒
         ctx.watch(toWatch)
-        Behaviors.immutable[Any] { (_, _) ⇒ Behaviors.same }
-          .onSignal {
+        Behaviors.receive[Any] { (_, _) ⇒ Behaviors.same }
+          .receiveSignal {
             case (_, s: Terminated) ⇒
               probe.ref ! "Terminated"
               Behaviors.stopped
diff --git a/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/BasicPersistentBehaviorsSpec.scala b/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/BasicPersistentBehaviorsSpec.scala
index 66e7738f9a..e4ca1f0b0e 100644
--- a/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/BasicPersistentBehaviorsSpec.scala
+++ b/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/BasicPersistentBehaviorsSpec.scala
@@ -15,7 +15,7 @@ object BasicPersistentBehaviorsSpec {
   case class State()
 
   val behavior: Behavior[Command] =
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "abc",
       initialState = State(),
       commandHandler = (ctx, state, cmd) ⇒ ???,
@@ -24,7 +24,7 @@ object BasicPersistentBehaviorsSpec {
 
   //#recovery
   val recoveryBehavior: Behavior[Command] =
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "abc",
       initialState = State(),
       commandHandler = (ctx, state, cmd) ⇒ ???,
@@ -36,7 +36,7 @@ object BasicPersistentBehaviorsSpec {
 
   //#tagging
   val taggingBehavior: Behavior[Command] =
-    PersistentBehaviors.immutable[Command, Event, State](
+    PersistentBehaviors.receive[Command, Event, State](
       persistenceId = "abc",
       initialState = State(),
       commandHandler = (ctx, state, cmd) ⇒ ???,
diff --git a/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/InDepthPersistentBehaviorSpec.scala b/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/InDepthPersistentBehaviorSpec.scala
index a7b5a4565f..892463f326 100644
--- a/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/InDepthPersistentBehaviorSpec.scala
+++ b/akka-persistence-typed/src/test/scala/docs/akka/persistence/typed/InDepthPersistentBehaviorSpec.scala
@@ -119,7 +119,7 @@ object InDepthPersistentBehaviorSpec {
 
   //#behavior
   def behavior(entityId: String): Behavior[BlogCommand] =
-    PersistentBehaviors.immutable[BlogCommand, BlogEvent, BlogState](
+    PersistentBehaviors.receive[BlogCommand, BlogEvent, BlogState](
       persistenceId = "Blog-" + entityId,
       initialState = BlogState.empty,
       commandHandler,
diff --git a/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/ActorSourceSinkSpec.scala b/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/ActorSourceSinkSpec.scala
index 88eaaee076..72cfc8360a 100644
--- a/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/ActorSourceSinkSpec.scala
+++ b/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/ActorSourceSinkSpec.scala
@@ -48,7 +48,7 @@ class ActorSourceSinkSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
     "obey protocol" in {
       val p = TestProbe[AckProto]()
 
-      val autoPilot = Behaviors.immutable[AckProto] {
+      val autoPilot = Behaviors.receive[AckProto] {
         (ctx, msg) ⇒
           msg match {
             case m @ Init(sender) ⇒
diff --git a/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/CustomGuardianAndMaterializerSpec.scala b/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/CustomGuardianAndMaterializerSpec.scala
index 480d8315bc..a3a0dfd23a 100644
--- a/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/CustomGuardianAndMaterializerSpec.scala
+++ b/akka-stream-typed/src/test/scala/akka/stream/typed/scaladsl/CustomGuardianAndMaterializerSpec.scala
@@ -25,7 +25,7 @@ object CustomGuardianAndMaterializerSpec {
 class CustomGuardianAndMaterializerSpec extends ActorTestKit with TypedAkkaSpecWithShutdown {
   import CustomGuardianAndMaterializerSpec._
 
-  val guardian = Behaviors.immutable[GuardianProtocol] {
+  val guardian = Behaviors.receive[GuardianProtocol] {
     (_, msg) ⇒ Behaviors.same
   }
 
diff --git a/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestKitUtils.scala b/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestKitUtils.scala
index 00b5a13231..5189d16e90 100644
--- a/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestKitUtils.scala
+++ b/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestKitUtils.scala
@@ -20,7 +20,7 @@ private[akka] object ActorTestKitGuardian {
   final case class SpawnActor[T](name: String, behavior: Behavior[T], replyTo: ActorRef[ActorRef[T]], props: Props) extends TestKitCommand
   final case class SpawnActorAnonymous[T](behavior: Behavior[T], replyTo: ActorRef[ActorRef[T]], props: Props) extends TestKitCommand
 
-  val testKitGuardian: Behavior[TestKitCommand] = Behaviors.immutable[TestKitCommand] {
+  val testKitGuardian: Behavior[TestKitCommand] = Behaviors.receive[TestKitCommand] {
     case (ctx, SpawnActor(name, behavior, reply, props)) ⇒
       reply ! ctx.spawn(behavior, name, props)
       Behaviors.same
diff --git a/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestProbeImpl.scala b/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestProbeImpl.scala
index 178945406e..460a08d6cf 100644
--- a/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestProbeImpl.scala
+++ b/akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/TestProbeImpl.scala
@@ -27,13 +27,13 @@ private[akka] object TestProbeImpl {
   private val testActorId = new AtomicInteger(0)
 
   private case class WatchActor[U](actor: ActorRef[U])
-  private def testActor[M](queue: BlockingDeque[M], terminations: BlockingDeque[Terminated]): Behavior[M] = Behaviors.immutable[M] { (ctx, msg) ⇒
+  private def testActor[M](queue: BlockingDeque[M], terminations: BlockingDeque[Terminated]): Behavior[M] = Behaviors.receive[M] { (ctx, msg) ⇒
     msg match {
       case WatchActor(ref) ⇒ ctx.watch(ref)
       case other           ⇒ queue.offerLast(other)
     }
     Behaviors.same
-  }.onSignal {
+  }.receiveSignal {
     case (_, t: Terminated) ⇒
       terminations.offerLast(t)
       Behaviors.same
diff --git a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/AsyncTestingExampleTest.java b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/AsyncTestingExampleTest.java
index 710cb4d794..6a564cc36b 100644
--- a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/AsyncTestingExampleTest.java
+++ b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/AsyncTestingExampleTest.java
@@ -35,7 +35,7 @@ public class AsyncTestingExampleTest {
     }
   }
 
-  Behavior<Ping> echoActor = Behaviors.immutable((ctx, ping) -> {
+  Behavior<Ping> echoActor = Behaviors.receive((ctx, ping) -> {
     ping.replyTo.tell(new Pong(ping.msg));
     return Behaviors.same();
   });
diff --git a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/ManualTimerExampleTest.java b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/ManualTimerExampleTest.java
index 0edbdaec5a..ca9f2c602b 100644
--- a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/ManualTimerExampleTest.java
+++ b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/ManualTimerExampleTest.java
@@ -35,7 +35,7 @@ public class ManualTimerExampleTest extends JUnitSuite {
     TestProbe<Tock> probe = testKit.createTestProbe();
     Behavior<Tick> behavior = Behaviors.withTimers(timer -> {
       timer.startSingleTimer("T", new Tick(), Duration.create(10, TimeUnit.MILLISECONDS));
-      return Behaviors.immutable( (ctx, tick) -> {
+      return Behaviors.receive( (ctx, tick) -> {
         probe.ref().tell(new Tock());
         return Behaviors.same();
       });
diff --git a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/SyncTestingExampleTest.java b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/SyncTestingExampleTest.java
index 2315e2e373..ff5f2c41de 100644
--- a/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/SyncTestingExampleTest.java
+++ b/akka-testkit-typed/src/test/java/akka/testkit/typed/javadsl/SyncTestingExampleTest.java
@@ -7,7 +7,6 @@ package akka.testkit.typed.javadsl;
 //#imports
 import akka.actor.typed.*;
 import akka.actor.typed.javadsl.*;
-import akka.testkit.typed.javadsl.*;
 //#imports
 import org.junit.Test;
 import org.scalatest.junit.JUnitSuite;
@@ -15,7 +14,7 @@ import org.scalatest.junit.JUnitSuite;
 public class SyncTestingExampleTest extends JUnitSuite {
 
   //#child
-  public static Behavior<String> childActor = Behaviors.immutable((ctx, msg) -> Behaviors.same());
+  public static Behavior<String> childActor = Behaviors.receive((ctx, msg) -> Behaviors.same());
   //#child
 
   //#under-test
@@ -42,7 +41,7 @@ public class SyncTestingExampleTest extends JUnitSuite {
     }
   }
 
-  public static Behavior<Command> myBehavior = Behaviors.immutable(Command.class)
+  public static Behavior<Command> myBehavior = Behaviors.receive(Command.class)
     .onMessage(CreateAChild.class, (ctx, msg) -> {
       ctx.spawn(childActor, msg.childName);
       return Behaviors.same();
diff --git a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/AsyncTestingExampleSpec.scala b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/AsyncTestingExampleSpec.scala
index 0c487fdefc..4ebf465268 100644
--- a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/AsyncTestingExampleSpec.scala
+++ b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/AsyncTestingExampleSpec.scala
@@ -13,7 +13,7 @@ object AsyncTestingExampleSpec {
   case class Ping(msg: String, response: ActorRef[Pong])
   case class Pong(msg: String)
 
-  val echoActor = Behaviors.immutable[Ping] { (_, msg) ⇒
+  val echoActor = Behaviors.receive[Ping] { (_, msg) ⇒
     msg match {
       case Ping(m, replyTo) ⇒
         replyTo ! Pong(m)
diff --git a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/BehaviorTestKitSpec.scala b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/BehaviorTestKitSpec.scala
index 933f30ec2a..e827d068fe 100644
--- a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/BehaviorTestKitSpec.scala
+++ b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/BehaviorTestKitSpec.scala
@@ -27,7 +27,7 @@ object BehaviorTestKitSpec {
 
     def behavior: Behavior[Command] = init()
 
-    def init(): Behavior[Command] = Behaviors.immutable[Command] { (ctx, msg) ⇒
+    def init(): Behavior[Command] = Behaviors.receive[Command] { (ctx, msg) ⇒
       msg match {
         case SpawnChildren(numberOfChildren) if numberOfChildren > 0 ⇒
           0.until(numberOfChildren).foreach { i ⇒
@@ -67,7 +67,7 @@ object BehaviorTestKitSpec {
 
     sealed trait Action
 
-    val initial: Behavior[Action] = Behaviors.immutable[Action] { (_, msg) ⇒
+    val initial: Behavior[Action] = Behaviors.receive[Action] { (_, msg) ⇒
       msg match {
         case _ ⇒
           Behaviors.empty
diff --git a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/ManualTimerExampleSpec.scala b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/ManualTimerExampleSpec.scala
index 05bfe8f7f7..d6f42a6f59 100644
--- a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/ManualTimerExampleSpec.scala
+++ b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/ManualTimerExampleSpec.scala
@@ -24,7 +24,7 @@ class ManualTimerExampleSpec extends AbstractActorSpec {
       val probe = TestProbe[Tock.type]()
       val behavior = Behaviors.withTimers[Tick.type] { timer ⇒
         timer.startSingleTimer("T", Tick, 10.millis)
-        Behaviors.immutable { (ctx, Tick) ⇒
+        Behaviors.receive { (ctx, Tick) ⇒
           probe.ref ! Tock
           Behaviors.same
         }
@@ -48,7 +48,7 @@ class ManualTimerExampleSpec extends AbstractActorSpec {
       val probe = TestProbe[Tock.type]()
       val behavior = Behaviors.withTimers[Tick.type] { timer ⇒
         timer.startPeriodicTimer("T", Tick, 10.millis)
-        Behaviors.immutable { (ctx, Tick) ⇒
+        Behaviors.receive { (ctx, Tick) ⇒
           probe.ref ! Tock
           Behaviors.same
         }
@@ -76,7 +76,7 @@ class ManualTimerExampleSpec extends AbstractActorSpec {
 
       val behavior = Behaviors.withTimers[Command] { timer ⇒
         timer.startPeriodicTimer("T", Tick(1), interval)
-        Behaviors.immutable { (ctx, cmd) ⇒
+        Behaviors.receive { (ctx, cmd) ⇒
           cmd match {
             case Tick(n) ⇒
               probe.ref ! Tock(n)
diff --git a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/SyncTestingExampleSpec.scala b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/SyncTestingExampleSpec.scala
index 36b368a324..b2cc6ef9bb 100644
--- a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/SyncTestingExampleSpec.scala
+++ b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/SyncTestingExampleSpec.scala
@@ -13,7 +13,7 @@ import org.scalatest.{ Matchers, WordSpec }
 
 object SyncTestingExampleSpec {
   //#child
-  val childActor = Behaviors.immutable[String] { (_, _) ⇒
+  val childActor = Behaviors.receiveMessage[String] { _ ⇒
     Behaviors.same[String]
   }
   //#child
@@ -26,7 +26,7 @@ object SyncTestingExampleSpec {
   case object SayHelloToAnonymousChild extends Cmd
   case class SayHello(who: ActorRef[String]) extends Cmd
 
-  val myBehavior = Behaviors.immutablePartial[Cmd] {
+  val myBehavior = Behaviors.receivePartial[Cmd] {
     case (ctx, CreateChild(name)) ⇒
       ctx.spawn(childActor, name)
       Behaviors.same
diff --git a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/TestProbeSpec.scala b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/TestProbeSpec.scala
index de4f81400a..e4223db543 100644
--- a/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/TestProbeSpec.scala
+++ b/akka-testkit-typed/src/test/scala/akka/testkit/typed/scaladsl/TestProbeSpec.scala
@@ -40,11 +40,11 @@ class TestProbeSpec extends AbstractActorSpec {
     "allow probing for actor stop when actor has not stopped yet" in {
       case object Stop
       val probe = TestProbe()
-      val ref = spawn(Behaviors.immutable[Stop.type]((ctx, message) ⇒
+      val ref = spawn(Behaviors.receive[Stop.type]((ctx, message) ⇒
         Behaviors.withTimers { (timer) ⇒
           timer.startSingleTimer("key", Stop, 300.millis)
 
-          Behaviors.immutable((ctx, stop) ⇒
+          Behaviors.receive((ctx, stop) ⇒
             Behaviors.stopped
           )
         }