MySerializer.scala

package my.akka.typed

import java.io.{PrintWriter, StringWriter}

import akka.serialization.{SerializationExtension, SerializerWithStringManifest}
import akka.typed.scaladsl._
import akka.typed.scaladsl.adapter._
import com.typesafe.config.{Config, ConfigFactory}

object MySerializer {
  def serializeTypedActorRef(config: Config): Unit = {
    val empty = Actor.immutable[String] { (_, msg) ⇒
      akka.typed.scaladsl.Actor.same
    }

    val system = akka.actor.ActorSystem("example", config)
    try {
      val original = system.spawn(empty, "empty")
      val serialization = SerializationExtension(system)

      val serializer = serialization.findSerializerFor(original)

      //Serializer for class akka.typed.internal.adapter.ActorRefAdapter = akka.serialization.JavaSerializer@7389af41
      println(s"Serializer for ${original.getClass} = " + serializer)

      // Turn it into bytes
      val bytes = serializer.toBinary(original)

      // Turn it back into an object
      val back = serialization.findSerializerFor(original) match {
        case s: SerializerWithStringManifest ⇒ s.fromBinary(bytes, s.manifest(original))
        case _ => serializer.fromBinary(bytes, manifest = None)
      }

      // Voilá!
      println(back, " ", back.getClass)
      println(original, " ", original.getClass)
    } catch {
      case t: Throwable => {
        val sw = new StringWriter
        t.printStackTrace(new PrintWriter(sw))
        println(t.getMessage)
        println(sw)
      }
    } finally {
      system.terminate()
    }
  }

  def main(args: Array[String]): Unit = {
    serializeTypedActorRef(
      ConfigFactory.parseString(
        """akka {
          |  actor {
          |    serialization-bindings {
          |      "akka.typed.ActorRef" = java
          |      "akka.typed.internal.adapter.ActorRefAdapter" = java
          |    }
          |  }
          |}
        """.stripMargin)
    )

    println("------------------------------------------------------")

    serializeTypedActorRef(ConfigFactory.parseString(""))

  }
}

output.txt

Serializer for class akka.typed.internal.adapter.ActorRefAdapter = akka.serialization.JavaSerializer@7364a7de
akka.typed.internal.adapter.ActorRefAdapter
java.io.NotSerializableException: akka.typed.internal.adapter.ActorRefAdapter
        at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
        at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
        at akka.serialization.JavaSerializer.$anonfun$toBinary$1(Serializer.scala:319)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
        at scala.util.DynamicVariable.withValue(DynamicVariable.scala:58)
        at akka.serialization.JavaSerializer.toBinary(Serializer.scala:319)
        at my.akka.typed.MySerializer$.serializeTypedActorRef(MySerializer.scala:27)
        at my.akka.typed.MySerializer$.main(MySerializer.scala:53)
        at my.akka.typed.MySerializer.main(MySerializer.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:497)
        at sbt.Run.invokeMain(Run.scala:67)
        at sbt.Run.run0(Run.scala:61)
        at sbt.Run.sbt$Run$$execute$1(Run.scala:51)
        at sbt.Run$$anonfun$run$1.apply$mcV$sp(Run.scala:55)
        at sbt.Run$$anonfun$run$1.apply(Run.scala:55)
        at sbt.Run$$anonfun$run$1.apply(Run.scala:55)
        at sbt.Logger$$anon$4.apply(Logger.scala:84)
        at sbt.TrapExit$App.run(TrapExit.scala:248)
        at java.lang.Thread.run(Thread.java:745)

------------------------------------------------------
Serializer for class akka.typed.internal.adapter.ActorRefAdapter = akka.typed.cluster.internal.MiscMessageSerializer@520d16bb
(Actor[akka://example/user/empty#1537921913], ,class akka.typed.internal.adapter.ActorRefAdapter)
(Actor[akka://example/user/empty#1537921913], ,class akka.typed.internal.adapter.ActorRefAdapter)