Merge branch 'master' into wip-2053d-actorbased-remote-drewhk

akka-actor-tests/src/test/java/akka/japi/JavaAPITestBase.java

@@ -1,5 +1,7 @@
 package akka.japi;
 
+import akka.event.LoggingAdapter;
+import akka.event.NoLogging;
 import org.junit.Test;
 
 import static org.junit.Assert.*;
@@ -46,4 +48,10 @@ public class JavaAPITestBase {
   public void shouldBeSingleton() {
     assertSame(Option.none(), Option.none());
   }
+
+  @Test
+  public void mustBeAbleToGetNoLogging() {
+      LoggingAdapter a = NoLogging.getInstance();
+      assertNotNull(a);
+  }
 }

akka-actor-tests/src/test/java/akka/routing/CustomRouteTest.java

@@ -15,7 +15,8 @@ public class CustomRouteTest {
   // only to test compilability
   public void testRoute() {
     final ActorRef ref = system.actorOf(new Props().withRouter(new RoundRobinRouter(1)));
-    final scala.Function1<scala.Tuple2<ActorRef, Object>, scala.collection.Iterable<Destination>> route = ExtractRoute.apply(ref);
+    final scala.Function1<scala.Tuple2<ActorRef, Object>,
+                          scala.collection.immutable.Iterable<Destination>> route = ExtractRoute.apply(ref);
     route.apply(null);
   }
   

akka-actor-tests/src/test/scala/akka/actor/ActorDSLSpec.scala

@@ -103,6 +103,32 @@ class ActorDSLSpec extends AkkaSpec {
       i.receive() must be("hi")
     }
 
+    "support becomeStacked" in {
+      //#becomeStacked
+      val a = actor(new Act {
+        become { // this will replace the initial (empty) behavior
+          case "info" ⇒ sender ! "A"
+          case "switch" ⇒
+            becomeStacked { // this will stack upon the "A" behavior
+              case "info"   ⇒ sender ! "B"
+              case "switch" ⇒ unbecome() // return to the "A" behavior
+            }
+          case "lobotomize" ⇒ unbecome() // OH NOES: Actor.emptyBehavior
+        }
+      })
+      //#becomeStacked
+
+      implicit def sender = testActor
+      a ! "info"
+      expectMsg("A")
+      a ! "switch"
+      a ! "info"
+      expectMsg("B")
+      a ! "switch"
+      a ! "info"
+      expectMsg("A")
+    }
+
     "support setup/teardown" in {
       //#simple-start-stop
       val a = actor(new Act {
@@ -188,7 +214,7 @@ class ActorDSLSpec extends AkkaSpec {
         become {
           case 1 ⇒ stash()
           case 2 ⇒
-            testActor ! 2; unstashAll(); become {
+            testActor ! 2; unstashAll(); becomeStacked {
               case 1 ⇒ testActor ! 1; unbecome()
             }
         }

akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala

@@ -4,14 +4,15 @@
 package akka.actor
 
 import language.postfixOps
+
 import akka.testkit._
 import org.scalatest.junit.JUnitSuite
 import com.typesafe.config.ConfigFactory
 import scala.concurrent.Await
 import scala.concurrent.duration._
-import scala.collection.JavaConverters
+import java.util.concurrent.{ RejectedExecutionException, ConcurrentLinkedQueue }
-import java.util.concurrent.{ TimeUnit, RejectedExecutionException, CountDownLatch, ConcurrentLinkedQueue }
 import akka.util.Timeout
+import akka.japi.Util.immutableSeq
 import scala.concurrent.Future
 import akka.pattern.ask
 
@@ -102,8 +103,6 @@ class ActorSystemSpec extends AkkaSpec("""akka.extensions = ["akka.actor.TestExt
     }
 
     "run termination callbacks in order" in {
-      import scala.collection.JavaConverters._
-
       val system2 = ActorSystem("TerminationCallbacks", AkkaSpec.testConf)
       val result = new ConcurrentLinkedQueue[Int]
       val count = 10
@@ -121,13 +120,11 @@ class ActorSystemSpec extends AkkaSpec("""akka.extensions = ["akka.actor.TestExt
       Await.ready(latch, 5 seconds)
 
       val expected = (for (i ← 1 to count) yield i).reverse
-      result.asScala.toSeq must be(expected)
 
+      immutableSeq(result) must be(expected)
     }
 
     "awaitTermination after termination callbacks" in {
-      import scala.collection.JavaConverters._
-
       val system2 = ActorSystem("AwaitTermination", AkkaSpec.testConf)
       @volatile
       var callbackWasRun = false

akka-actor-tests/src/test/scala/akka/actor/IOActor.scala

@@ -14,7 +14,7 @@ import akka.dispatch.MessageDispatcher
 import akka.pattern.ask
 import java.net.{ Socket, InetSocketAddress, InetAddress, SocketAddress }
 import scala.util.Failure
-import annotation.tailrec
+import scala.annotation.tailrec
 
 object IOActorSpec {
 
@@ -55,6 +55,8 @@ object IOActorSpec {
 
     def receive = {
 
+      case _: IO.Connected ⇒ //don't care
+
       case bytes: ByteString ⇒
         val source = sender
         socket write bytes
@@ -65,9 +67,9 @@ object IOActorSpec {
 
       case IO.Closed(`socket`, cause) ⇒
         state(cause)
-        throw cause match {
+        cause match {
-          case IO.Error(e) ⇒ e
+          case IO.Error(e) ⇒ throw e
-          case _           ⇒ new RuntimeException("Socket closed")
+          case _           ⇒ throw new RuntimeException("Socket closed")
         }
     }
 
@@ -154,6 +156,8 @@ object IOActorSpec {
       case IO.Read(socket, bytes) ⇒
         state(socket)(IO Chunk bytes)
 
+      case _: IO.Connected ⇒ //don't care
+
       case IO.Closed(socket, cause) ⇒
         state -= socket
 
@@ -181,6 +185,8 @@ object IOActorSpec {
           readResult map (source !)
         }
 
+      case _: IO.Connected ⇒ //don't care
+
       case IO.Read(`socket`, bytes) ⇒
         state(IO Chunk bytes)
 
@@ -276,7 +282,7 @@ class IOActorSpec extends AkkaSpec with DefaultTimeout {
   }
 
   "an IO Actor" must {
-    implicit val ec = system.dispatcher
+    import system.dispatcher
     "run echo server" in {
       filterException[java.net.ConnectException] {
         val addressPromise = Promise[SocketAddress]()

akka-actor-tests/src/test/scala/akka/actor/LocalActorRefProviderSpec.scala

@@ -43,9 +43,10 @@ class LocalActorRefProviderSpec extends AkkaSpec(LocalActorRefProviderSpec.confi
       val childName = "akka%3A%2F%2FClusterSystem%40127.0.0.1%3A2552"
       val a = system.actorOf(Props(new Actor {
         val child = context.actorOf(Props.empty, name = childName)
-        assert(childName == child.path.name)
         def receive = {
-          case "lookup" ⇒ sender ! context.actorFor(childName)
+          case "lookup" ⇒
+            if (childName == child.path.name) sender ! context.actorFor(childName)
+            else sender ! s"$childName is not ${child.path.name}!"
         }
       }))
       a.tell("lookup", testActor)

akka-actor-tests/src/test/scala/akka/actor/RelativeActorPathSpec.scala

@@ -6,24 +6,22 @@ package akka.actor
 import org.scalatest.WordSpec
 import org.scalatest.matchers.MustMatchers
 import java.net.URLEncoder
+import scala.collection.immutable
 
 class RelativeActorPathSpec extends WordSpec with MustMatchers {
 
-  def elements(path: String): Seq[String] = path match {
+  def elements(path: String): immutable.Seq[String] = RelativeActorPath.unapply(path).getOrElse(Nil)
-    case RelativeActorPath(elem) ⇒ elem.toSeq
-    case _                       ⇒ Nil
-  }
 
   "RelativeActorPath" must {
     "match single name" in {
-      elements("foo") must be(Seq("foo"))
+      elements("foo") must be(List("foo"))
     }
     "match path separated names" in {
-      elements("foo/bar/baz") must be(Seq("foo", "bar", "baz"))
+      elements("foo/bar/baz") must be(List("foo", "bar", "baz"))
     }
     "match url encoded name" in {
       val name = URLEncoder.encode("akka://ClusterSystem@127.0.0.1:2552", "UTF-8")
-      elements(name) must be(Seq(name))
+      elements(name) must be(List(name))
     }
   }
 }

akka-actor-tests/src/test/scala/akka/actor/SupervisorHierarchySpec.scala

@@ -194,7 +194,7 @@ object SupervisorHierarchySpec {
       case x ⇒ (x, x)
     }
     override val supervisorStrategy = OneForOneStrategy()(unwrap andThen {
-      case _: Failure if pongsToGo > 0 ⇒
+      case (_: Failure, _) if pongsToGo > 0 ⇒
         log :+= Event("pongOfDeath resuming " + sender, identityHashCode(this))
         Resume
       case (f: Failure, orig) ⇒
@@ -391,10 +391,10 @@ object SupervisorHierarchySpec {
 
     // don’t escalate from this one!
     override val supervisorStrategy = OneForOneStrategy() {
-      case f: Failure                               ⇒ f.directive
+      case f: Failure ⇒ f.directive
-      case OriginalRestartException(f: Failure)     ⇒ f.directive
+      case OriginalRestartException(f: Failure) ⇒ f.directive
-      case ActorInitializationException(f: Failure) ⇒ f.directive
+      case ActorInitializationException(_, _, f: Failure) ⇒ f.directive
-      case _                                        ⇒ Stop
+      case _ ⇒ Stop
     }
 
     var children = Vector.empty[ActorRef]

akka-actor-tests/src/test/scala/akka/actor/TypedActorSpec.scala

@@ -5,18 +5,19 @@ package akka.actor
 
 import language.postfixOps
 import org.scalatest.{ BeforeAndAfterAll, BeforeAndAfterEach }
-import akka.util.Timeout
+import scala.annotation.tailrec
+import scala.collection.immutable
 import scala.concurrent.{ Await, Future, Promise }
 import scala.concurrent.duration._
-import java.util.concurrent.atomic.AtomicReference
-import annotation.tailrec
 import akka.testkit.{ EventFilter, filterEvents, AkkaSpec }
+import akka.util.Timeout
 import akka.japi.{ Option ⇒ JOption }
 import akka.testkit.DefaultTimeout
-import akka.dispatch.{ Dispatchers }
+import akka.dispatch.Dispatchers
 import akka.pattern.ask
 import akka.serialization.JavaSerializer
 import akka.actor.TypedActor._
+import java.util.concurrent.atomic.AtomicReference
 import java.lang.IllegalStateException
 import java.util.concurrent.{ TimeoutException, TimeUnit, CountDownLatch }
 
@@ -35,9 +36,9 @@ object TypedActorSpec {
     }
     """
 
-  class CyclicIterator[T](val items: Seq[T]) extends Iterator[T] {
+  class CyclicIterator[T](val items: immutable.Seq[T]) extends Iterator[T] {
 
-    private[this] val current: AtomicReference[Seq[T]] = new AtomicReference(items)
+    private[this] val current = new AtomicReference(items)
 
     def hasNext = items != Nil
 

akka-actor-tests/src/test/scala/akka/config/ConfigSpec.scala

@@ -45,6 +45,9 @@ class ConfigSpec extends AkkaSpec(ConfigFactory.defaultReference(ActorSystem.fin
 
         getInt("akka.actor.deployment.default.virtual-nodes-factor") must be(10)
         settings.DefaultVirtualNodesFactor must be(10)
+
+        getMilliseconds("akka.actor.unstarted-push-timeout") must be(10.seconds.toMillis)
+        settings.UnstartedPushTimeout.duration must be(10.seconds)
       }
 
       {

akka-actor-tests/src/test/scala/akka/dispatch/PriorityDispatcherSpec.scala

@@ -6,10 +6,9 @@ import org.junit.runner.RunWith
 import org.scalatest.junit.JUnitRunner
 import com.typesafe.config.Config
 
-import akka.actor.{ Props, InternalActorRef, ActorSystem, Actor }
+import akka.actor.{ Props, ActorSystem, Actor }
 import akka.pattern.ask
 import akka.testkit.{ DefaultTimeout, AkkaSpec }
-import scala.concurrent.Await
 import scala.concurrent.duration._
 
 object PriorityDispatcherSpec {
@@ -50,24 +49,23 @@ class PriorityDispatcherSpec extends AkkaSpec(PriorityDispatcherSpec.config) wit
   }
 
   def testOrdering(dispatcherKey: String) {
+    val msgs = (1 to 100) toList
 
     val actor = system.actorOf(Props(new Actor {
-      var acc: List[Int] = Nil
+
+      val acc = scala.collection.mutable.ListBuffer[Int]()
+
+      scala.util.Random.shuffle(msgs) foreach { m ⇒ self ! m }
+
+      self.tell('Result, testActor)
 
       def receive = {
-        case i: Int  ⇒ acc = i :: acc
+        case i: Int  ⇒ acc += i
-        case 'Result ⇒ sender ! acc
+        case 'Result ⇒ sender ! acc.toList
       }
-    }).withDispatcher(dispatcherKey)).asInstanceOf[InternalActorRef]
+    }).withDispatcher(dispatcherKey))
 
-    actor.suspend //Make sure the actor isn't treating any messages, let it buffer the incoming messages
+    expectMsgType[List[_]] must be === msgs
-
-    val msgs = (1 to 100).toList
-    for (m ← msgs) actor ! m
-
-    actor.resume(causedByFailure = null) //Signal the actor to start treating it's message backlog
-
-    Await.result(actor.?('Result).mapTo[List[Int]], timeout.duration) must be === msgs.reverse
   }
 
 }

akka-actor-tests/src/test/scala/akka/performance/workbench/BenchResultRepository.scala

@@ -12,17 +12,18 @@ import java.io.PrintWriter
 import java.text.SimpleDateFormat
 import java.util.Date
 import scala.collection.mutable.{ Map ⇒ MutableMap }
+import scala.collection.immutable
 import akka.actor.ActorSystem
 import akka.event.Logging
 
 trait BenchResultRepository {
   def add(stats: Stats)
 
-  def get(name: String): Seq[Stats]
+  def get(name: String): immutable.Seq[Stats]
 
   def get(name: String, load: Int): Option[Stats]
 
-  def getWithHistorical(name: String, load: Int): Seq[Stats]
+  def getWithHistorical(name: String, load: Int): immutable.Seq[Stats]
 
   def isBaseline(stats: Stats): Boolean
 
@@ -38,9 +39,9 @@ object BenchResultRepository {
 }
 
 class FileBenchResultRepository extends BenchResultRepository {
-  private val statsByName = MutableMap[String, Seq[Stats]]()
+  private val statsByName = MutableMap[String, immutable.Seq[Stats]]()
   private val baselineStats = MutableMap[Key, Stats]()
-  private val historicalStats = MutableMap[Key, Seq[Stats]]()
+  private val historicalStats = MutableMap[Key, immutable.Seq[Stats]]()
   private def resultDir = BenchmarkConfig.config.getString("benchmark.resultDir")
   private val serDir = resultDir + "/ser"
   private def serDirExists: Boolean = new File(serDir).exists
@@ -51,13 +52,13 @@ class FileBenchResultRepository extends BenchResultRepository {
   case class Key(name: String, load: Int)
 
   def add(stats: Stats): Unit = synchronized {
-    val values = statsByName.getOrElseUpdate(stats.name, IndexedSeq.empty)
+    val values = statsByName.getOrElseUpdate(stats.name, Vector.empty)
     statsByName(stats.name) = values :+ stats
     save(stats)
   }
 
-  def get(name: String): Seq[Stats] = synchronized {
+  def get(name: String): immutable.Seq[Stats] = synchronized {
-    statsByName.getOrElse(name, IndexedSeq.empty)
+    statsByName.getOrElse(name, Vector.empty)
   }
 
   def get(name: String, load: Int): Option[Stats] = synchronized {
@@ -68,13 +69,13 @@ class FileBenchResultRepository extends BenchResultRepository {
     baselineStats.get(Key(stats.name, stats.load)) == Some(stats)
   }
 
-  def getWithHistorical(name: String, load: Int): Seq[Stats] = synchronized {
+  def getWithHistorical(name: String, load: Int): immutable.Seq[Stats] = synchronized {
     val key = Key(name, load)
-    val historical = historicalStats.getOrElse(key, IndexedSeq.empty)
+    val historical = historicalStats.getOrElse(key, Vector.empty)
     val baseline = baselineStats.get(key)
     val current = get(name, load)
 
-    val limited = (IndexedSeq.empty ++ historical ++ baseline ++ current).takeRight(maxHistorical)
+    val limited = (Vector.empty ++ historical ++ baseline ++ current).takeRight(maxHistorical)
     limited.sortBy(_.timestamp)
   }
 
@@ -94,7 +95,7 @@ class FileBenchResultRepository extends BenchResultRepository {
       }
       val historical = load(historicalFiles)
       for (h ← historical) {
-        val values = historicalStats.getOrElseUpdate(Key(h.name, h.load), IndexedSeq.empty)
+        val values = historicalStats.getOrElseUpdate(Key(h.name, h.load), Vector.empty)
         historicalStats(Key(h.name, h.load)) = values :+ h
       }
     }
@@ -120,7 +121,7 @@ class FileBenchResultRepository extends BenchResultRepository {
     }
   }
 
-  private def load(files: Iterable[File]): Seq[Stats] = {
+  private def load(files: Iterable[File]): immutable.Seq[Stats] = {
     val result =
       for (f ← files) yield {
         var in: ObjectInputStream = null
@@ -132,11 +133,11 @@ class FileBenchResultRepository extends BenchResultRepository {
           case e: Throwable ⇒
             None
         } finally {
-          if (in ne null) try { in.close() } catch { case ignore: Exception ⇒ }
+          if (in ne null) try in.close() catch { case ignore: Exception ⇒ }
         }
       }
 
-    result.flatten.toSeq.sortBy(_.timestamp)
+    result.flatten.toVector.sortBy(_.timestamp)
   }
 
   loadFiles()

akka-actor-tests/src/test/scala/akka/performance/workbench/GoogleChartBuilder.scala

@@ -3,7 +3,7 @@ package akka.performance.workbench
 import java.io.UnsupportedEncodingException
 import java.net.URLEncoder
 
-import scala.collection.immutable.TreeMap
+import scala.collection.immutable
 
 /**
  * Generates URLs to Google Chart API http://code.google.com/apis/chart/
@@ -16,7 +16,7 @@ object GoogleChartBuilder {
   /**
    * Builds a bar chart for tps in the statistics.
    */
-  def tpsChartUrl(statsByTimestamp: TreeMap[Long, Seq[Stats]], title: String, legend: Stats ⇒ String): String = {
+  def tpsChartUrl(statsByTimestamp: immutable.TreeMap[Long, Seq[Stats]], title: String, legend: Stats ⇒ String): String = {
     if (statsByTimestamp.isEmpty) ""
     else {
       val loads = statsByTimestamp.values.head.map(_.load)
@@ -46,7 +46,7 @@ object GoogleChartBuilder {
       //sb.append("&")
 
       // legend
-      val legendStats = statsByTimestamp.values.map(_.head).toSeq
+      val legendStats = statsByTimestamp.values.toVector.map(_.head)
       appendLegend(legendStats, sb, legend)
       sb.append("&")
       // bar spacing
@@ -60,10 +60,7 @@ object GoogleChartBuilder {
       val loadStr = loads.mkString(",")
       sb.append("chd=t:")
       val maxValue = allStats.map(_.tps).max
-      val tpsSeries: Iterable[String] =
+      val tpsSeries: Iterable[String] = for (statsSeq ← statsByTimestamp.values) yield statsSeq.map(_.tps).mkString(",")
-        for (statsSeq ← statsByTimestamp.values) yield {
-          statsSeq.map(_.tps).mkString(",")
-        }
       sb.append(tpsSeries.mkString("|"))
 
       // y range
@@ -83,7 +80,7 @@ object GoogleChartBuilder {
   /**
    * Builds a bar chart for all percentiles and the mean in the statistics.
    */
-  def percentilesAndMeanChartUrl(statistics: Seq[Stats], title: String, legend: Stats ⇒ String): String = {
+  def percentilesAndMeanChartUrl(statistics: immutable.Seq[Stats], title: String, legend: Stats ⇒ String): String = {
     if (statistics.isEmpty) ""
     else {
       val current = statistics.last
@@ -146,13 +143,13 @@ object GoogleChartBuilder {
     }
   }
 
-  private def percentileLabels(percentiles: TreeMap[Int, Long], sb: StringBuilder) {
+  private def percentileLabels(percentiles: immutable.TreeMap[Int, Long], sb: StringBuilder) {
     sb.append("chxl=1:|")
     val s = percentiles.keys.toList.map(_ + "%").mkString("|")
     sb.append(s)
   }
 
-  private def appendLegend(statistics: Seq[Stats], sb: StringBuilder, legend: Stats ⇒ String) {
+  private def appendLegend(statistics: immutable.Seq[Stats], sb: StringBuilder, legend: Stats ⇒ String) {
     val legends = statistics.map(legend(_))
     sb.append("chdl=")
     val s = legends.map(urlEncode(_)).mkString("|")
@@ -166,7 +163,7 @@ object GoogleChartBuilder {
     sb.append(s)
   }
 
-  private def dataSeries(allPercentiles: Seq[TreeMap[Int, Long]], meanValues: Seq[Double], sb: StringBuilder) {
+  private def dataSeries(allPercentiles: immutable.Seq[immutable.TreeMap[Int, Long]], meanValues: immutable.Seq[Double], sb: StringBuilder) {
     val percentileSeries =
       for {
         percentiles ← allPercentiles
@@ -181,7 +178,7 @@ object GoogleChartBuilder {
     sb.append(series.mkString("|"))
   }
 
-  private def dataSeries(values: Seq[Double], sb: StringBuilder) {
+  private def dataSeries(values: immutable.Seq[Double], sb: StringBuilder) {
     val series = values.map(formatDouble(_))
     sb.append(series.mkString("|"))
   }
@@ -198,7 +195,7 @@ object GoogleChartBuilder {
     }
   }
 
-  def latencyAndThroughputChartUrl(statistics: Seq[Stats], title: String): String = {
+  def latencyAndThroughputChartUrl(statistics: immutable.Seq[Stats], title: String): String = {
     if (statistics.isEmpty) ""
     else {
       val sb = new StringBuilder

akka-actor-tests/src/test/scala/akka/performance/workbench/Report.scala

@@ -5,7 +5,7 @@ import java.text.SimpleDateFormat
 import java.util.Date
 import akka.actor.ActorSystem
 import akka.event.Logging
-import scala.collection.immutable.TreeMap
+import scala.collection.immutable
 
 class Report(
   system: ActorSystem,
@@ -19,7 +19,7 @@ class Report(
   val legendTimeFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm")
   val fileTimestampFormat = new SimpleDateFormat("yyyyMMddHHmmss")
 
-  def html(statistics: Seq[Stats]) {
+  def html(statistics: immutable.Seq[Stats]) {
 
     val current = statistics.last
     val sb = new StringBuilder
@@ -80,13 +80,13 @@ class Report(
     chartUrl
   }
 
-  def comparePercentilesAndMeanChart(stats: Stats): Seq[String] = {
+  def comparePercentilesAndMeanChart(stats: Stats): immutable.Seq[String] = {
     for {
-      compareName ← compareResultWith.toSeq
+      compareName ← compareResultWith.to[immutable.Seq]
       compareStats ← resultRepository.get(compareName, stats.load)
     } yield {
       val chartTitle = stats.name + " vs. " + compareName + ", " + stats.load + " clients" + ", Percentiles and Mean (microseconds)"
-      val chartUrl = GoogleChartBuilder.percentilesAndMeanChartUrl(Seq(compareStats, stats), chartTitle, _.name)
+      val chartUrl = GoogleChartBuilder.percentilesAndMeanChartUrl(List(compareStats, stats), chartTitle, _.name)
       chartUrl
     }
   }
@@ -102,17 +102,17 @@ class Report(
     }
   }
 
-  def compareWithHistoricalTpsChart(statistics: Seq[Stats]): Option[String] = {
+  def compareWithHistoricalTpsChart(statistics: immutable.Seq[Stats]): Option[String] = {
 
     if (statistics.isEmpty) {
       None
     } else {
       val histTimestamps = resultRepository.getWithHistorical(statistics.head.name, statistics.head.load).map(_.timestamp)
-      val statsByTimestamp = TreeMap[Long, Seq[Stats]]() ++
+      val statsByTimestamp = immutable.TreeMap[Long, Seq[Stats]]() ++
         (for (ts ← histTimestamps) yield {
           val seq =
             for (stats ← statistics) yield {
-              val withHistorical: Seq[Stats] = resultRepository.getWithHistorical(stats.name, stats.load)
+              val withHistorical: immutable.Seq[Stats] = resultRepository.getWithHistorical(stats.name, stats.load)
               val cell = withHistorical.find(_.timestamp == ts)
               cell.getOrElse(Stats(stats.name, stats.load, ts))
             }
@@ -131,7 +131,7 @@ class Report(
     chartUrl
   }
 
-  def formatResultsTable(statsSeq: Seq[Stats]): String = {
+  def formatResultsTable(statsSeq: immutable.Seq[Stats]): String = {
 
     val name = statsSeq.head.name
 

akka-actor-tests/src/test/scala/akka/routing/CustomRouteSpec.scala

@@ -19,7 +19,7 @@ class CustomRouteSpec extends AkkaSpec {
       provider.createRoutees(1)
 
       {
-        case (sender, message: String) ⇒ Seq(Destination(sender, target))
+        case (sender, message: String) ⇒ List(Destination(sender, target))
         case (sender, message)         ⇒ toAll(sender, provider.routees)
       }
     }
@@ -43,8 +43,8 @@ class CustomRouteSpec extends AkkaSpec {
       val r = Await.result(router.ask(CurrentRoutees)(1 second).
         mapTo[RouterRoutees], 1 second)
       r.routees.size must be(1)
-      route(testActor -> "hallo") must be(Seq(Destination(testActor, target)))
+      route(testActor -> "hallo") must be(List(Destination(testActor, target)))
-      route(testActor -> 12) must be(Seq(Destination(testActor, r.routees.head)))
+      route(testActor -> 12) must be(List(Destination(testActor, r.routees.head)))
       //#test-route
     }
 

akka-actor-tests/src/test/scala/akka/routing/ResizerSpec.scala

@@ -10,10 +10,9 @@ import akka.testkit.TestEvent._
 import akka.actor.Props
 import scala.concurrent.Await
 import scala.concurrent.duration._
+import scala.collection.immutable
 import akka.actor.ActorRef
-import java.util.concurrent.atomic.AtomicInteger
 import akka.pattern.ask
-import java.util.concurrent.TimeoutException
 import scala.util.Try
 
 object ResizerSpec {
@@ -61,10 +60,10 @@ class ResizerSpec extends AkkaSpec(ResizerSpec.config) with DefaultTimeout with
         lowerBound = 2,
         upperBound = 3)
 
-      val c1 = resizer.capacity(IndexedSeq.empty[ActorRef])
+      val c1 = resizer.capacity(immutable.IndexedSeq.empty[ActorRef])
       c1 must be(2)
 
-      val current = IndexedSeq(system.actorOf(Props[TestActor]), system.actorOf(Props[TestActor]))
+      val current = immutable.IndexedSeq(system.actorOf(Props[TestActor]), system.actorOf(Props[TestActor]))
       val c2 = resizer.capacity(current)
       c2 must be(0)
     }

akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala

@@ -5,9 +5,8 @@ package akka.routing
 
 import language.postfixOps
 
-import java.util.concurrent.atomic.AtomicInteger
 import akka.actor._
-import scala.collection.mutable.LinkedList
+import scala.collection.immutable
 import akka.testkit._
 import scala.concurrent.duration._
 import scala.concurrent.Await
@@ -17,7 +16,9 @@ import akka.pattern.{ ask, pipe }
 import java.util.concurrent.ConcurrentHashMap
 import com.typesafe.config.Config
 import akka.dispatch.Dispatchers
+import akka.util.Collections.EmptyImmutableSeq
 import akka.util.Timeout
+import java.util.concurrent.atomic.AtomicInteger
 
 object RoutingSpec {
 
@@ -54,11 +55,10 @@ object RoutingSpec {
   class MyRouter(config: Config) extends RouterConfig {
     val foo = config.getString("foo")
     def createRoute(routeeProvider: RouteeProvider): Route = {
-      val routees = IndexedSeq(routeeProvider.context.actorOf(Props[Echo]))
+      routeeProvider.registerRoutees(List(routeeProvider.context.actorOf(Props[Echo])))
-      routeeProvider.registerRoutees(routees)
 
       {
-        case (sender, message) ⇒ Nil
+        case (sender, message) ⇒ EmptyImmutableSeq
       }
     }
     def routerDispatcher: String = Dispatchers.DefaultDispatcherId
@@ -101,33 +101,34 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
     }
 
     "be able to send their routees" in {
-      class TheActor extends Actor {
+      case class TestRun(id: String, names: immutable.Iterable[String], actors: Int)
-        val routee1 = context.actorOf(Props[TestActor], "routee1")
+      val actor = system.actorOf(Props(new Actor {
-        val routee2 = context.actorOf(Props[TestActor], "routee2")
-        val routee3 = context.actorOf(Props[TestActor], "routee3")
-        val router = context.actorOf(Props[TestActor].withRouter(
-          ScatterGatherFirstCompletedRouter(
-            routees = List(routee1, routee2, routee3),
-            within = 5 seconds)))
-
         def receive = {
-          case "doIt"                 ⇒ router ! CurrentRoutees
+          case TestRun(id, names, actors) ⇒
-          case routees: RouterRoutees ⇒ testActor forward routees
+            val routerProps = Props[TestActor].withRouter(
+              ScatterGatherFirstCompletedRouter(
+                routees = names map { context.actorOf(Props(new TestActor), _) },
+                within = 5 seconds))
+
+            1 to actors foreach { i ⇒ context.actorOf(routerProps, id + i).tell(CurrentRoutees, testActor) }
         }
-      }
+      }))
 
-      val theActor = system.actorOf(Props(new TheActor), "theActor")
+      val actors = 15
-      theActor ! "doIt"
+      val names = 1 to 20 map { "routee" + _ } toList
-      val routees = expectMsgPF() {
-        case RouterRoutees(routees) ⇒ routees.toSet
-      }
 
-      routees.map(_.path.name) must be(Set("routee1", "routee2", "routee3"))
+      actor ! TestRun("test", names, actors)
+      1 to actors foreach { _ ⇒
+        val routees = expectMsgType[RouterRoutees].routees
+        routees.map(_.path.name) must be === names
+      }
+      expectNoMsg(500.millis)
     }
 
     "use configured nr-of-instances when FromConfig" in {
       val router = system.actorOf(Props[TestActor].withRouter(FromConfig), "router1")
-      Await.result(router ? CurrentRoutees, remaining).asInstanceOf[RouterRoutees].routees.size must be(3)
+      router ! CurrentRoutees
+      expectMsgType[RouterRoutees].routees.size must be(3)
       watch(router)
       system.stop(router)
       expectMsgType[Terminated]
@@ -135,7 +136,8 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
 
     "use configured nr-of-instances when router is specified" in {
       val router = system.actorOf(Props[TestActor].withRouter(RoundRobinRouter(nrOfInstances = 2)), "router2")
-      Await.result(router ? CurrentRoutees, remaining).asInstanceOf[RouterRoutees].routees.size must be(3)
+      router ! CurrentRoutees
+      expectMsgType[RouterRoutees].routees.size must be(3)
       system.stop(router)
     }
 
@@ -150,7 +152,8 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
       }
       val router = system.actorOf(Props[TestActor].withRouter(RoundRobinRouter(resizer = Some(resizer))), "router3")
       Await.ready(latch, remaining)
-      Await.result(router ? CurrentRoutees, remaining).asInstanceOf[RouterRoutees].routees.size must be(3)
+      router ! CurrentRoutees
+      expectMsgType[RouterRoutees].routees.size must be(3)
       system.stop(router)
     }
 
@@ -251,15 +254,15 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
       val doneLatch = new TestLatch(connectionCount)
 
       //lets create some connections.
-      var actors = new LinkedList[ActorRef]
+      @volatile var actors = immutable.IndexedSeq[ActorRef]()
-      var counters = new LinkedList[AtomicInteger]
+      @volatile var counters = immutable.IndexedSeq[AtomicInteger]()
       for (i ← 0 until connectionCount) {
         counters = counters :+ new AtomicInteger()
 
         val actor = system.actorOf(Props(new Actor {
           def receive = {
             case "end"    ⇒ doneLatch.countDown()
-            case msg: Int ⇒ counters.get(i).get.addAndGet(msg)
+            case msg: Int ⇒ counters(i).addAndGet(msg)
           }
         }))
         actors = actors :+ actor
@@ -278,10 +281,8 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
       //now wait some and do validations.
       Await.ready(doneLatch, remaining)
 
-      for (i ← 0 until connectionCount) {
+      for (i ← 0 until connectionCount)
-        val counter = counters.get(i).get
+        counters(i).get must be((iterationCount * (i + 1)))
-        counter.get must be((iterationCount * (i + 1)))
-      }
     }
 
     "deliver a broadcast message using the !" in {

akka-actor-tests/src/test/scala/akka/util/DurationSpec.scala

@@ -8,10 +8,31 @@ import language.postfixOps
 import org.scalatest.WordSpec
 import org.scalatest.matchers.MustMatchers
 import scala.concurrent.duration._
+import scala.concurrent.Await
 
 import java.util.concurrent.TimeUnit._
+import akka.testkit.AkkaSpec
+import akka.testkit.TestLatch
+import java.util.concurrent.TimeoutException
+import akka.testkit.LongRunningTest
 
-class DurationSpec extends WordSpec with MustMatchers {
+class DurationSpec extends AkkaSpec {
+
+  "A HashedWheelTimer" must {
+
+    "not mess up long timeouts" taggedAs LongRunningTest in {
+      val longish = Long.MaxValue.nanos
+      val barrier = TestLatch()
+      import system.dispatcher
+      val job = system.scheduler.scheduleOnce(longish)(barrier.countDown())
+      intercept[TimeoutException] {
+        // this used to fire after 46 seconds due to wrap-around
+        Await.ready(barrier, 90 seconds)
+      }
+      job.cancel()
+    }
+
+  }
 
   "Duration" must {
 

akka-actor/src/main/java/akka/japi/JAPI.java

@@ -5,7 +5,7 @@ import scala.collection.Seq;
 public class JAPI {
 
   public static <T> Seq<T> seq(T... ts) {
-    return Util.arrayToSeq(ts);
+    return Util.immutableSeq(ts);
   }
   
 }

akka-actor/src/main/java/akka/util/internal/HashedWheelTimer.java

@@ -263,8 +263,11 @@ public class HashedWheelTimer implements Timer {
 
     void scheduleTimeout(HashedWheelTimeout timeout, long delay) {
         // Prepare the required parameters to schedule the timeout object.
-        final long relativeIndex = Math.max(1, (delay + tickDuration - 1) / tickDuration); // If relative index < 1 then it should be 1
+        long relativeIndex = (delay + tickDuration - 1) / tickDuration;
-
+        // if the previous line had an overflow going on, then we’ll just schedule this timeout
+        // one tick early; that shouldn’t matter since we’re talking 270 years here
+        if (relativeIndex < 0) relativeIndex = delay / tickDuration;
+        if (relativeIndex == 0) relativeIndex = 1;
         final long remainingRounds = relativeIndex / wheel.length;
 
         // Add the timeout to the wheel.
@@ -304,7 +307,7 @@ public class HashedWheelTimer implements Timer {
 
             while (!shutdown()) {
                 final long deadline = waitForNextTick();
-                if (deadline > 0)
+                if (deadline > Long.MIN_VALUE)
                     notifyExpiredTimeouts(fetchExpiredTimeouts(deadline));
             }
         }
@@ -332,7 +335,7 @@ public class HashedWheelTimer implements Timer {
                 HashedWheelTimeout timeout = i.next();
                 if (timeout.remainingRounds <= 0) {
                     i.remove();
-                    if (timeout.deadline <= deadline) {
+                    if (timeout.deadline - deadline <= 0) {
                         expiredTimeouts.add(timeout);
                     } else {
                         // Handle the case where the timeout is put into a wrong
@@ -368,6 +371,12 @@ public class HashedWheelTimer implements Timer {
             expiredTimeouts.clear();
         }
 
+        /**
+         * calculate goal nanoTime from startTime and current tick number,
+         * then wait until that goal has been reached.
+         * 
+         * @return Long.MIN_VALUE if received a shutdown request, current time otherwise (with Long.MIN_VALUE changed by +1)
+         */
         private long waitForNextTick() {
             long deadline = startTime + tickDuration * tick;
 
@@ -378,7 +387,8 @@ public class HashedWheelTimer implements Timer {
 
                 if (sleepTimeMs <= 0) {
                     tick += 1;
-                    return currentTime;
+                    if (currentTime == Long.MIN_VALUE) return -Long.MAX_VALUE;
+                    else return currentTime;
                 }
 
                 // Check if we run on windows, as if thats the case we will need
@@ -394,7 +404,7 @@ public class HashedWheelTimer implements Timer {
                     Thread.sleep(sleepTimeMs);
                 } catch (InterruptedException e) {
                     if (shutdown()) {
-                        return -1;
+                        return Long.MIN_VALUE;
                     }
                 }
             }

akka-actor/src/main/scala/akka/actor/ActorCell.scala

@@ -6,7 +6,7 @@ package akka.actor
 
 import java.io.{ ObjectOutputStream, NotSerializableException }
 import scala.annotation.tailrec
-import scala.collection.immutable.TreeSet
+import scala.collection.immutable
 import scala.concurrent.duration.Duration
 import scala.util.control.NonFatal
 import akka.actor.dungeon.ChildrenContainer
@@ -76,8 +76,14 @@ trait ActorContext extends ActorRefFactory {
 
   /**
    * Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler.
-   * Puts the behavior on top of the hotswap stack.
+   * This method acts upon the behavior stack as follows:
-   * If "discardOld" is true, an unbecome will be issued prior to pushing the new behavior to the stack
+   *
+   *  - if `discardOld = true` it will replace the top element (i.e. the current behavior)
+   *  - if `discardOld = false` it will keep the current behavior and push the given one atop
+   *
+   * The default of replacing the current behavior has been chosen to avoid memory leaks in
+   * case client code is written without consulting this documentation first (i.e. always pushing
+   * new closures and never issuing an `unbecome()`)
    */
   def become(behavior: Actor.Receive, discardOld: Boolean = true): Unit
 
@@ -102,7 +108,7 @@ trait ActorContext extends ActorRefFactory {
    * val goodLookup = context.actorFor("kid")
    * }}}
    */
-  def children: Iterable[ActorRef]
+  def children: immutable.Iterable[ActorRef]
 
   /**
    * Get the child with the given name if it exists.
@@ -167,14 +173,20 @@ trait UntypedActorContext extends ActorContext {
 
   /**
    * Changes the Actor's behavior to become the new 'Procedure' handler.
-   * Puts the behavior on top of the hotswap stack.
+   * Replaces the current behavior at the top of the hotswap stack.
    */
   def become(behavior: Procedure[Any]): Unit
 
   /**
    * Changes the Actor's behavior to become the new 'Procedure' handler.
-   * Puts the behavior on top of the hotswap stack.
+   * This method acts upon the behavior stack as follows:
-   * If "discardOld" is true, an unbecome will be issued prior to pushing the new behavior to the stack
+   *
+   *  - if `discardOld = true` it will replace the top element (i.e. the current behavior)
+   *  - if `discardOld = false` it will keep the current behavior and push the given one atop
+   *
+   * The default of replacing the current behavior has been chosen to avoid memory leaks in
+   * case client code is written without consulting this documentation first (i.e. always pushing
+   * new closures and never issuing an `unbecome()`)
    */
   def become(behavior: Procedure[Any], discardOld: Boolean): Unit
 
@@ -247,12 +259,12 @@ private[akka] trait Cell {
    */
   def isLocal: Boolean
   /**
-   * If the actor isLocal, returns whether messages are currently queued,
+   * If the actor isLocal, returns whether "user messages" are currently queued,
    * “false” otherwise.
    */
   def hasMessages: Boolean
   /**
-   * If the actor isLocal, returns the number of messages currently queued,
+   * If the actor isLocal, returns the number of "user messages" currently queued,
    * which may be a costly operation, 0 otherwise.
    */
   def numberOfMessages: Int
@@ -275,7 +287,7 @@ private[akka] object ActorCell {
 
   final val emptyBehaviorStack: List[Actor.Receive] = Nil
 
-  final val emptyActorRefSet: Set[ActorRef] = TreeSet.empty
+  final val emptyActorRefSet: Set[ActorRef] = immutable.TreeSet.empty
 }
 
 //ACTORCELL IS 64bytes and should stay that way unless very good reason not to (machine sympathy, cache line fit)

akka-actor/src/main/scala/akka/actor/ActorPath.scala

@@ -3,6 +3,8 @@
  */
 package akka.actor
 import scala.annotation.tailrec
+import scala.collection.immutable
+import akka.japi.Util.immutableSeq
 import java.net.MalformedURLException
 
 object ActorPath {
@@ -20,6 +22,8 @@ object ActorPath {
    * http://www.ietf.org/rfc/rfc2396.txt
    */
   val ElementRegex = """(?:[-\w:@&=+,.!~*'_;]|%\p{XDigit}{2})(?:[-\w:@&=+,.!~*'$_;]|%\p{XDigit}{2})*""".r
+
+  private[akka] final val emptyActorPath: immutable.Iterable[String] = List("")
 }
 
 /**
@@ -68,23 +72,18 @@ sealed trait ActorPath extends Comparable[ActorPath] with Serializable {
   /**
    * ''Java API'': Recursively create a descendant’s path by appending all child names.
    */
-  def descendant(names: java.lang.Iterable[String]): ActorPath = {
+  def descendant(names: java.lang.Iterable[String]): ActorPath = /(immutableSeq(names))
-    import scala.collection.JavaConverters._
-    /(names.asScala)
-  }
 
   /**
    * Sequence of names for this path from root to this. Performance implication: has to allocate a list.
    */
-  def elements: Iterable[String]
+  def elements: immutable.Iterable[String]
 
   /**
    * ''Java API'': Sequence of names for this path from root to this. Performance implication: has to allocate a list.
    */
-  def getElements: java.lang.Iterable[String] = {
+  def getElements: java.lang.Iterable[String] =
-    import scala.collection.JavaConverters._
+    scala.collection.JavaConverters.asJavaIterableConverter(elements).asJava
-    elements.asJava
-  }
 
   /**
    * Walk up the tree to obtain and return the RootActorPath.
@@ -112,7 +111,7 @@ final case class RootActorPath(address: Address, name: String = "/") extends Act
 
   override def /(child: String): ActorPath = new ChildActorPath(this, child)
 
-  override val elements: Iterable[String] = List("")
+  override def elements: immutable.Iterable[String] = ActorPath.emptyActorPath
 
   override val toString: String = address + name
 
@@ -121,7 +120,7 @@ final case class RootActorPath(address: Address, name: String = "/") extends Act
     else addr + name
 
   override def compareTo(other: ActorPath): Int = other match {
-    case r: RootActorPath  ⇒ toString compareTo r.toString
+    case r: RootActorPath  ⇒ toString compareTo r.toString // FIXME make this cheaper by comparing address and name in isolation
     case c: ChildActorPath ⇒ 1
   }
 }
@@ -134,9 +133,9 @@ final class ChildActorPath(val parent: ActorPath, val name: String) extends Acto
 
   override def /(child: String): ActorPath = new ChildActorPath(this, child)
 
-  override def elements: Iterable[String] = {
+  override def elements: immutable.Iterable[String] = {
     @tailrec
-    def rec(p: ActorPath, acc: List[String]): Iterable[String] = p match {
+    def rec(p: ActorPath, acc: List[String]): immutable.Iterable[String] = p match {
       case r: RootActorPath ⇒ acc
       case _                ⇒ rec(p.parent, p.name :: acc)
     }

akka-actor/src/main/scala/akka/actor/ActorRef.scala

@@ -419,7 +419,10 @@ private[akka] trait MinimalActorRef extends InternalActorRef with LocalRef {
  * to the ActorSystem's EventStream
  */
 @SerialVersionUID(1L)
-case class DeadLetter(message: Any, sender: ActorRef, recipient: ActorRef)
+case class DeadLetter(message: Any, sender: ActorRef, recipient: ActorRef) {
+  require(sender ne null, "DeadLetter sender may not be null")
+  require(recipient ne null, "DeadLetter recipient may not be null")
+}
 
 private[akka] object DeadLetterActorRef {
   @SerialVersionUID(1L)
@@ -446,8 +449,11 @@ private[akka] class EmptyLocalActorRef(override val provider: ActorRefProvider,
   override def sendSystemMessage(message: SystemMessage): Unit = specialHandle(message)
 
   override def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit = message match {
-    case d: DeadLetter ⇒ specialHandle(d.message) // do NOT form endless loops, since deadLetters will resend!
+    case d: DeadLetter ⇒
-    case _             ⇒ if (!specialHandle(message)) eventStream.publish(DeadLetter(message, sender, this))
+      specialHandle(d.message) // do NOT form endless loops, since deadLetters will resend!
+    case _ if !specialHandle(message) ⇒
+      eventStream.publish(DeadLetter(message, if (sender eq Actor.noSender) provider.deadLetters else sender, this))
+    case _ ⇒
   }
 
   protected def specialHandle(msg: Any): Boolean = msg match {
@@ -530,7 +536,7 @@ private[akka] class VirtualPathContainer(
 
   def hasChildren: Boolean = !children.isEmpty
 
-  def foreachChild(f: ActorRef ⇒ Unit) = {
+  def foreachChild(f: ActorRef ⇒ Unit): Unit = {
     val iter = children.values.iterator
     while (iter.hasNext) f(iter.next)
   }

akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala

@@ -8,8 +8,9 @@ import akka.dispatch._
 import akka.routing._
 import akka.event._
 import akka.util.{ Switch, Helpers }
+import akka.japi.Util.immutableSeq
+import akka.util.Collections.EmptyImmutableSeq
 import scala.util.{ Success, Failure }
-import scala.util.control.NonFatal
 import scala.concurrent.{ Future, Promise }
 import java.util.concurrent.atomic.AtomicLong
 
@@ -271,10 +272,7 @@ trait ActorRefFactory {
    *
    * For maximum performance use a collection with efficient head & tail operations.
    */
-  def actorFor(path: java.lang.Iterable[String]): ActorRef = {
+  def actorFor(path: java.lang.Iterable[String]): ActorRef = provider.actorFor(lookupRoot, immutableSeq(path))
-    import scala.collection.JavaConverters._
-    provider.actorFor(lookupRoot, path.asScala)
-  }
 
   /**
    * Construct an [[akka.actor.ActorSelection]] from the given path, which is
@@ -480,7 +478,7 @@ class LocalActorRefProvider(
   def registerExtraNames(_extras: Map[String, InternalActorRef]): Unit = extraNames ++= _extras
 
   private def guardianSupervisorStrategyConfigurator =
-    dynamicAccess.createInstanceFor[SupervisorStrategyConfigurator](settings.SupervisorStrategyClass, Seq()).get
+    dynamicAccess.createInstanceFor[SupervisorStrategyConfigurator](settings.SupervisorStrategyClass, EmptyImmutableSeq).get
 
   /**
    * Overridable supervision strategy to be used by the “/user” guardian.

akka-actor/src/main/scala/akka/actor/ActorSystem.scala

@@ -6,20 +6,20 @@ package akka.actor
 
 import akka.event._
 import akka.dispatch._
-import akka.pattern.ask
+import akka.japi.Util.immutableSeq
 import com.typesafe.config.{ Config, ConfigFactory }
 import scala.annotation.tailrec
-import scala.concurrent.duration.Duration
+import scala.collection.immutable
-import java.io.Closeable
+import scala.concurrent.duration.{ FiniteDuration, Duration }
 import scala.concurrent.{ Await, Awaitable, CanAwait, Future }
+import scala.util.{ Failure, Success }
 import scala.util.control.NonFatal
 import akka.util._
+import java.io.Closeable
 import akka.util.internal.{ HashedWheelTimer, ConcurrentIdentityHashMap }
 import java.util.concurrent.{ ThreadFactory, CountDownLatch, TimeoutException, RejectedExecutionException }
 import java.util.concurrent.TimeUnit.MILLISECONDS
 import akka.actor.dungeon.ChildrenContainer
-import scala.concurrent.duration.FiniteDuration
-import util.{ Failure, Success }
 
 object ActorSystem {
 
@@ -144,7 +144,7 @@ object ActorSystem {
 
     final val LogLevel: String = getString("akka.loglevel")
     final val StdoutLogLevel: String = getString("akka.stdout-loglevel")
-    final val EventHandlers: Seq[String] = getStringList("akka.event-handlers").asScala
+    final val EventHandlers: immutable.Seq[String] = immutableSeq(getStringList("akka.event-handlers"))
     final val EventHandlerStartTimeout: Timeout = Timeout(Duration(getMilliseconds("akka.event-handler-startup-timeout"), MILLISECONDS))
     final val LogConfigOnStart: Boolean = config.getBoolean("akka.log-config-on-start")
 
@@ -273,10 +273,7 @@ abstract class ActorSystem extends ActorRefFactory {
   /**
    * ''Java API'': Recursively create a descendant’s path by appending all child names.
    */
-  def descendant(names: java.lang.Iterable[String]): ActorPath = {
+  def descendant(names: java.lang.Iterable[String]): ActorPath = /(immutableSeq(names))
-    import scala.collection.JavaConverters._
-    /(names.asScala)
-  }
 
   /**
    * Start-up time in milliseconds since the epoch.
@@ -536,7 +533,7 @@ private[akka] class ActorSystemImpl(val name: String, applicationConfig: Config,
   val scheduler: Scheduler = createScheduler()
 
   val provider: ActorRefProvider = {
-    val arguments = Seq(
+    val arguments = Vector(
       classOf[String] -> name,
       classOf[Settings] -> settings,
       classOf[EventStream] -> eventStream,
@@ -676,9 +673,8 @@ private[akka] class ActorSystemImpl(val name: String, applicationConfig: Config,
   def hasExtension(ext: ExtensionId[_ <: Extension]): Boolean = findExtension(ext) != null
 
   private def loadExtensions() {
-    import scala.collection.JavaConverters.collectionAsScalaIterableConverter
+    immutableSeq(settings.config.getStringList("akka.extensions")) foreach { fqcn ⇒
-    settings.config.getStringList("akka.extensions").asScala foreach { fqcn ⇒
+      dynamicAccess.getObjectFor[AnyRef](fqcn) recoverWith { case _ ⇒ dynamicAccess.createInstanceFor[AnyRef](fqcn, Nil) } match {
-      dynamicAccess.getObjectFor[AnyRef](fqcn) recoverWith { case _ ⇒ dynamicAccess.createInstanceFor[AnyRef](fqcn, Seq()) } match {
         case Success(p: ExtensionIdProvider) ⇒ registerExtension(p.lookup())
         case Success(p: ExtensionId[_])      ⇒ registerExtension(p)
         case Success(other)                  ⇒ log.error("[{}] is not an 'ExtensionIdProvider' or 'ExtensionId', skipping...", fqcn)

akka-actor/src/main/scala/akka/actor/Address.scala

@@ -5,7 +5,8 @@ package akka.actor
 import java.net.URI
 import java.net.URISyntaxException
 import java.net.MalformedURLException
-import annotation.tailrec
+import scala.annotation.tailrec
+import scala.collection.immutable
 
 /**
  * The address specifies the physical location under which an Actor can be
@@ -71,7 +72,7 @@ private[akka] trait PathUtils {
 }
 
 object RelativeActorPath extends PathUtils {
-  def unapply(addr: String): Option[Iterable[String]] = {
+  def unapply(addr: String): Option[immutable.Seq[String]] = {
     try {
       val uri = new URI(addr)
       if (uri.isAbsolute) None
@@ -119,13 +120,12 @@ object AddressFromURIString {
  * Given an ActorPath it returns the Address and the path elements if the path is well-formed
  */
 object ActorPathExtractor extends PathUtils {
-  def unapply(addr: String): Option[(Address, Iterable[String])] =
+  def unapply(addr: String): Option[(Address, immutable.Iterable[String])] =
     try {
       val uri = new URI(addr)
-      if (uri.getRawPath == null) None
+      uri.getRawPath match {
-      else AddressFromURIString.unapply(uri) match {
+        case null ⇒ None
-        case None       ⇒ None
+        case path ⇒ AddressFromURIString.unapply(uri).map((_, split(path).drop(1)))
-        case Some(addr) ⇒ Some((addr, split(uri.getRawPath).drop(1)))
       }
     } catch {
       case _: URISyntaxException ⇒ None

akka-actor/src/main/scala/akka/actor/Deployer.scala

@@ -7,10 +7,11 @@ package akka.actor
 import scala.concurrent.duration.Duration
 import com.typesafe.config._
 import akka.routing._
+import akka.japi.Util.immutableSeq
 import java.util.concurrent.{ TimeUnit }
 import akka.util.WildcardTree
 import java.util.concurrent.atomic.AtomicReference
-import annotation.tailrec
+import scala.annotation.tailrec
 
 /**
  * This class represents deployment configuration for a given actor path. It is
@@ -141,7 +142,7 @@ private[akka] class Deployer(val settings: ActorSystem.Settings, val dynamicAcce
 
     val deployment = config.withFallback(default)
 
-    val routees = Vector() ++ deployment.getStringList("routees.paths").asScala
+    val routees = immutableSeq(deployment.getStringList("routees.paths"))
 
     val nrOfInstances = deployment.getInt("nr-of-instances")
 
@@ -160,7 +161,7 @@ private[akka] class Deployer(val settings: ActorSystem.Settings, val dynamicAcce
         val vnodes = deployment.getInt("virtual-nodes-factor")
         ConsistentHashingRouter(nrOfInstances, routees, resizer, virtualNodesFactor = vnodes)
       case fqn ⇒
-        val args = Seq(classOf[Config] -> deployment)
+        val args = List(classOf[Config] -> deployment)
         dynamicAccess.createInstanceFor[RouterConfig](fqn, args).recover({
           case exception ⇒ throw new IllegalArgumentException(
             ("Cannot instantiate router [%s], defined in [%s], " +

akka-actor/src/main/scala/akka/actor/DynamicAccess.scala

@@ -3,7 +3,7 @@
  */
 package akka.actor
 
-import scala.util.control.NonFatal
+import scala.collection.immutable
 import java.lang.reflect.InvocationTargetException
 import scala.reflect.ClassTag
 import scala.util.Try
@@ -25,7 +25,7 @@ abstract class DynamicAccess {
    * val obj = DynamicAccess.createInstanceFor(clazz, Seq(classOf[Config] -> config, classOf[String] -> name))
    * }}}
    */
-  def createInstanceFor[T: ClassTag](clazz: Class[_], args: Seq[(Class[_], AnyRef)]): Try[T]
+  def createInstanceFor[T: ClassTag](clazz: Class[_], args: immutable.Seq[(Class[_], AnyRef)]): Try[T]
 
   /**
    * Obtain a `Class[_]` object loaded with the right class loader (i.e. the one
@@ -40,7 +40,7 @@ abstract class DynamicAccess {
    * `args` argument. The exact usage of args depends on which type is requested,
    * see the relevant requesting code for details.
    */
-  def createInstanceFor[T: ClassTag](fqcn: String, args: Seq[(Class[_], AnyRef)]): Try[T]
+  def createInstanceFor[T: ClassTag](fqcn: String, args: immutable.Seq[(Class[_], AnyRef)]): Try[T]
 
   /**
    * Obtain the Scala “object” instance for the given fully-qualified class name, if there is one.
@@ -70,7 +70,7 @@ class ReflectiveDynamicAccess(val classLoader: ClassLoader) extends DynamicAcces
       if (t.isAssignableFrom(c)) c else throw new ClassCastException(t + " is not assignable from " + c)
     })
 
-  override def createInstanceFor[T: ClassTag](clazz: Class[_], args: Seq[(Class[_], AnyRef)]): Try[T] =
+  override def createInstanceFor[T: ClassTag](clazz: Class[_], args: immutable.Seq[(Class[_], AnyRef)]): Try[T] =
     Try {
       val types = args.map(_._1).toArray
       val values = args.map(_._2).toArray
@@ -81,7 +81,7 @@ class ReflectiveDynamicAccess(val classLoader: ClassLoader) extends DynamicAcces
       if (t.isInstance(obj)) obj.asInstanceOf[T] else throw new ClassCastException(clazz.getName + " is not a subtype of " + t)
     } recover { case i: InvocationTargetException if i.getTargetException ne null ⇒ throw i.getTargetException }
 
-  override def createInstanceFor[T: ClassTag](fqcn: String, args: Seq[(Class[_], AnyRef)]): Try[T] =
+  override def createInstanceFor[T: ClassTag](fqcn: String, args: immutable.Seq[(Class[_], AnyRef)]): Try[T] =
     getClassFor(fqcn) flatMap { c ⇒ createInstanceFor(c, args) }
 
   override def getObjectFor[T: ClassTag](fqcn: String): Try[T] = {

akka-actor/src/main/scala/akka/actor/Extension.scala

@@ -98,5 +98,5 @@ abstract class ExtensionKey[T <: Extension](implicit m: ClassTag[T]) extends Ext
   def this(clazz: Class[T]) = this()(ClassTag(clazz))
 
   override def lookup(): ExtensionId[T] = this
-  def createExtension(system: ExtendedActorSystem): T = system.dynamicAccess.createInstanceFor[T](m.runtimeClass, Seq(classOf[ExtendedActorSystem] -> system)).get
+  def createExtension(system: ExtendedActorSystem): T = system.dynamicAccess.createInstanceFor[T](m.runtimeClass, List(classOf[ExtendedActorSystem] -> system)).get
 }

akka-actor/src/main/scala/akka/actor/FSM.scala

@@ -521,7 +521,7 @@ trait FSM[S, D] extends Listeners with ActorLogging {
    *       Main actor receive() method
    * *******************************************
    */
-  override final def receive: Receive = {
+  override def receive: Receive = {
     case TimeoutMarker(gen) ⇒
       if (generation == gen) {
         processMsg(StateTimeout, "state timeout")

akka-actor/src/main/scala/akka/actor/FaultHandling.scala

@@ -5,10 +5,13 @@ package akka.actor
 
 import language.implicitConversions
 
-import java.util.concurrent.TimeUnit
-import scala.collection.mutable.ArrayBuffer
 import java.lang.{ Iterable ⇒ JIterable }
+import java.util.concurrent.TimeUnit
+import akka.japi.Util.immutableSeq
+import scala.collection.mutable.ArrayBuffer
+import scala.collection.immutable
 import scala.concurrent.duration.Duration
+
 /**
  * INTERNAL API
  */
@@ -170,7 +173,7 @@ object SupervisorStrategy extends SupervisorStrategyLowPriorityImplicits {
    * Implicit conversion from `Seq` of Throwables to a `Decider`.
    * This maps the given Throwables to restarts, otherwise escalates.
    */
-  implicit def seqThrowable2Decider(trapExit: Seq[Class[_ <: Throwable]]): Decider = makeDecider(trapExit)
+  implicit def seqThrowable2Decider(trapExit: immutable.Seq[Class[_ <: Throwable]]): Decider = makeDecider(trapExit)
 
   type Decider = PartialFunction[Throwable, Directive]
   type JDecider = akka.japi.Function[Throwable, Directive]
@@ -180,25 +183,16 @@ object SupervisorStrategy extends SupervisorStrategyLowPriorityImplicits {
    * Decider builder which just checks whether one of
    * the given Throwables matches the cause and restarts, otherwise escalates.
    */
-  def makeDecider(trapExit: Array[Class[_]]): Decider =
+  def makeDecider(trapExit: immutable.Seq[Class[_ <: Throwable]]): Decider = {
-    { case x ⇒ if (trapExit exists (_ isInstance x)) Restart else Escalate }
+    case x ⇒ if (trapExit exists (_ isInstance x)) Restart else Escalate
-
-  /**
-   * Decider builder which just checks whether one of
-   * the given Throwables matches the cause and restarts, otherwise escalates.
-   */
-  def makeDecider(trapExit: Seq[Class[_ <: Throwable]]): Decider =
-    { case x ⇒ if (trapExit exists (_ isInstance x)) Restart else Escalate }
-
-  /**
-   * Decider builder which just checks whether one of
-   * the given Throwables matches the cause and restarts, otherwise escalates.
-   */
-  def makeDecider(trapExit: JIterable[Class[_ <: Throwable]]): Decider = {
-    import scala.collection.JavaConverters.iterableAsScalaIterableConverter
-    makeDecider(trapExit.asScala.toSeq)
   }
 
+  /**
+   * Decider builder which just checks whether one of
+   * the given Throwables matches the cause and restarts, otherwise escalates.
+   */
+  def makeDecider(trapExit: JIterable[Class[_ <: Throwable]]): Decider = makeDecider(immutableSeq(trapExit))
+
   /**
    * Decider builder for Iterables of cause-directive pairs, e.g. a map obtained
    * from configuration; will sort the pairs so that the most specific type is
@@ -222,14 +216,14 @@ object SupervisorStrategy extends SupervisorStrategyLowPriorityImplicits {
    *
    * INTERNAL API
    */
-  private[akka] def sort(in: Iterable[CauseDirective]): Seq[CauseDirective] =
+  private[akka] def sort(in: Iterable[CauseDirective]): immutable.Seq[CauseDirective] =
     (new ArrayBuffer[CauseDirective](in.size) /: in) { (buf, ca) ⇒
       buf.indexWhere(_._1 isAssignableFrom ca._1) match {
         case -1 ⇒ buf append ca
         case x  ⇒ buf insert (x, ca)
       }
       buf
-    }
+    }.to[immutable.IndexedSeq]
 
   private[akka] def withinTimeRangeOption(withinTimeRange: Duration): Option[Duration] =
     if (withinTimeRange.isFinite && withinTimeRange >= Duration.Zero) Some(withinTimeRange) else None
@@ -338,10 +332,6 @@ case class AllForOneStrategy(maxNrOfRetries: Int = -1, withinTimeRange: Duration
 
   def this(maxNrOfRetries: Int, withinTimeRange: Duration, trapExit: JIterable[Class[_ <: Throwable]]) =
     this(maxNrOfRetries, withinTimeRange)(SupervisorStrategy.makeDecider(trapExit))
-
-  def this(maxNrOfRetries: Int, withinTimeRange: Duration, trapExit: Array[Class[_]]) =
-    this(maxNrOfRetries, withinTimeRange)(SupervisorStrategy.makeDecider(trapExit))
-
   /*
    *  this is a performance optimization to avoid re-allocating the pairs upon
    *  every call to requestRestartPermission, assuming that strategies are shared
@@ -380,9 +370,6 @@ case class OneForOneStrategy(maxNrOfRetries: Int = -1, withinTimeRange: Duration
   def this(maxNrOfRetries: Int, withinTimeRange: Duration, trapExit: JIterable[Class[_ <: Throwable]]) =
     this(maxNrOfRetries, withinTimeRange)(SupervisorStrategy.makeDecider(trapExit))
 
-  def this(maxNrOfRetries: Int, withinTimeRange: Duration, trapExit: Array[Class[_]]) =
-    this(maxNrOfRetries, withinTimeRange)(SupervisorStrategy.makeDecider(trapExit))
-
   /*
    *  this is a performance optimization to avoid re-allocating the pairs upon
    *  every call to requestRestartPermission, assuming that strategies are shared

akka-actor/src/main/scala/akka/actor/IO.scala

@@ -6,6 +6,7 @@ package akka.actor
 import language.higherKinds
 import language.postfixOps
 
+import scala.collection.immutable
 import scala.concurrent.{ ExecutionContext, Future }
 import scala.concurrent.duration.Duration
 import scala.util.control.NonFatal
@@ -122,7 +123,7 @@ object IO {
      * @return a new SocketHandle that can be used to perform actions on the
      *         new connection's SocketChannel.
      */
-    def accept(options: Seq[SocketOption] = Seq.empty)(implicit socketOwner: ActorRef): SocketHandle = {
+    def accept(options: immutable.Seq[SocketOption] = Nil)(implicit socketOwner: ActorRef): SocketHandle = {
       val socket = SocketHandle(socketOwner, ioManager)
       ioManager ! Accept(socket, this, options)
       socket
@@ -250,7 +251,7 @@ object IO {
    *
    * Normally sent using IOManager.listen()
    */
-  case class Listen(server: ServerHandle, address: SocketAddress, options: Seq[ServerSocketOption] = Seq.empty) extends IOMessage
+  case class Listen(server: ServerHandle, address: SocketAddress, options: immutable.Seq[ServerSocketOption] = Nil) extends IOMessage
 
   /**
    * Message from an [[akka.actor.IOManager]] that the ServerSocketChannel is
@@ -272,7 +273,7 @@ object IO {
    *
    * Normally sent using [[akka.actor.IO.ServerHandle]].accept()
    */
-  case class Accept(socket: SocketHandle, server: ServerHandle, options: Seq[SocketOption] = Seq.empty) extends IOMessage
+  case class Accept(socket: SocketHandle, server: ServerHandle, options: immutable.Seq[SocketOption] = Nil) extends IOMessage
 
   /**
    * Message to an [[akka.actor.IOManager]] to create a SocketChannel connected
@@ -280,7 +281,7 @@ object IO {
    *
    * Normally sent using IOManager.connect()
    */
-  case class Connect(socket: SocketHandle, address: SocketAddress, options: Seq[SocketOption] = Seq.empty) extends IOMessage
+  case class Connect(socket: SocketHandle, address: SocketAddress, options: immutable.Seq[SocketOption] = Nil) extends IOMessage
 
   /**
    * Message from an [[akka.actor.IOManager]] that the SocketChannel has
@@ -832,7 +833,7 @@ final class IOManager private (system: ExtendedActorSystem) extends Extension {
    * @param option Seq of [[akka.actor.IO.ServerSocketOptions]] to setup on socket
    * @return a [[akka.actor.IO.ServerHandle]] to uniquely identify the created socket
    */
-  def listen(address: SocketAddress, options: Seq[IO.ServerSocketOption])(implicit owner: ActorRef): IO.ServerHandle = {
+  def listen(address: SocketAddress, options: immutable.Seq[IO.ServerSocketOption])(implicit owner: ActorRef): IO.ServerHandle = {
     val server = IO.ServerHandle(owner, actor)
     actor ! IO.Listen(server, address, options)
     server
@@ -847,7 +848,7 @@ final class IOManager private (system: ExtendedActorSystem) extends Extension {
    * @param owner the ActorRef that will receive messages from the IOManagerActor
    * @return a [[akka.actor.IO.ServerHandle]] to uniquely identify the created socket
    */
-  def listen(address: SocketAddress)(implicit owner: ActorRef): IO.ServerHandle = listen(address, Seq.empty)
+  def listen(address: SocketAddress)(implicit owner: ActorRef): IO.ServerHandle = listen(address, Nil)
 
   /**
    * Create a ServerSocketChannel listening on a host and port. Messages will
@@ -860,7 +861,7 @@ final class IOManager private (system: ExtendedActorSystem) extends Extension {
    * @param owner the ActorRef that will receive messages from the IOManagerActor
    * @return a [[akka.actor.IO.ServerHandle]] to uniquely identify the created socket
    */
-  def listen(host: String, port: Int, options: Seq[IO.ServerSocketOption] = Seq.empty)(implicit owner: ActorRef): IO.ServerHandle =
+  def listen(host: String, port: Int, options: immutable.Seq[IO.ServerSocketOption] = Nil)(implicit owner: ActorRef): IO.ServerHandle =
     listen(new InetSocketAddress(host, port), options)(owner)
 
   /**
@@ -873,7 +874,7 @@ final class IOManager private (system: ExtendedActorSystem) extends Extension {
    * @param owner the ActorRef that will receive messages from the IOManagerActor
    * @return a [[akka.actor.IO.SocketHandle]] to uniquely identify the created socket
    */
-  def connect(address: SocketAddress, options: Seq[IO.SocketOption] = Seq.empty)(implicit owner: ActorRef): IO.SocketHandle = {
+  def connect(address: SocketAddress, options: immutable.Seq[IO.SocketOption] = Nil)(implicit owner: ActorRef): IO.SocketHandle = {
     val socket = IO.SocketHandle(owner, actor)
     actor ! IO.Connect(socket, address, options)
     socket
@@ -991,7 +992,7 @@ final class IOManagerActor(val settings: Settings) extends Actor with ActorLoggi
 
   private def forwardFailure(f: ⇒ Unit): Unit = try f catch { case NonFatal(e) ⇒ sender ! Status.Failure(e) }
 
-  private def setSocketOptions(socket: java.net.Socket, options: Seq[IO.SocketOption]) {
+  private def setSocketOptions(socket: java.net.Socket, options: immutable.Seq[IO.SocketOption]) {
     options foreach {
       case IO.KeepAlive(on)           ⇒ forwardFailure(socket.setKeepAlive(on))
       case IO.OOBInline(on)           ⇒ forwardFailure(socket.setOOBInline(on))

akka-actor/src/main/scala/akka/actor/RepointableActorRef.scala

@@ -189,15 +189,16 @@ private[akka] class UnstartedCell(val systemImpl: ActorSystemImpl, val self: Rep
   def childrenRefs: ChildrenContainer = ChildrenContainer.EmptyChildrenContainer
   def getChildByName(name: String): Option[ChildRestartStats] = None
   def tell(message: Any, sender: ActorRef): Unit = {
+    val useSender = if (sender eq Actor.noSender) system.deadLetters else sender
     if (lock.tryLock(timeout, TimeUnit.MILLISECONDS)) {
       try {
-        if (self.underlying eq this) queue enqueue Envelope(message, sender, system)
+        if (self.underlying eq this) queue enqueue Envelope(message, useSender, system)
-        else self.underlying.tell(message, sender)
+        else self.underlying.tell(message, useSender)
       } finally {
         lock.unlock()
       }
     } else {
-      system.deadLetters ! DeadLetter(message, sender, self)
+      system.deadLetters ! DeadLetter(message, useSender, self)
     }
   }
   def sendSystemMessage(msg: SystemMessage): Unit = {

akka-actor/src/main/scala/akka/actor/Scheduler.scala

@@ -203,8 +203,8 @@ class DefaultScheduler(hashedWheelTimer: HashedWheelTimer, log: LoggingAdapter)
   }
 
   override def close(): Unit = {
-    import scala.collection.JavaConverters._
+    val i = hashedWheelTimer.stop().iterator()
-    hashedWheelTimer.stop().asScala foreach execDirectly
+    while (i.hasNext) execDirectly(i.next())
   }
 }
 

akka-actor/src/main/scala/akka/actor/Stash.scala

@@ -16,13 +16,13 @@ import akka.AkkaException
  *      def receive = {
  *        case "open" ⇒
  *          unstashAll()
- *          context.become {
+ *          context.become({
  *            case "write" ⇒ // do writing...
  *            case "close" ⇒
  *              unstashAll()
  *              context.unbecome()
  *            case msg ⇒ stash()
- *          }
+ *          }, discardOld = false)
  *        case "done" ⇒ // done
  *        case msg    ⇒ stash()
  *      }

akka-actor/src/main/scala/akka/actor/TypedActor.scala

@@ -4,22 +4,25 @@
 package akka.actor
 
 import language.existentials
-import akka.japi.{ Creator, Option ⇒ JOption }
+
-import java.lang.reflect.{ InvocationTargetException, Method, InvocationHandler, Proxy }
-import akka.util.Timeout
 import scala.util.control.NonFatal
+import scala.util.{ Try, Success, Failure }
+import scala.collection.immutable
+import scala.concurrent.duration.FiniteDuration
 import scala.concurrent.duration.Duration
+import scala.reflect.ClassTag
 import scala.concurrent.{ Await, Future }
+import akka.japi.{ Creator, Option ⇒ JOption }
+import akka.japi.Util.{ immutableSeq, immutableSingletonSeq }
+import akka.util.Timeout
 import akka.util.Reflect.instantiator
+import akka.serialization.{ JavaSerializer, SerializationExtension }
 import akka.dispatch._
 import java.util.concurrent.atomic.{ AtomicReference ⇒ AtomVar }
 import java.util.concurrent.TimeoutException
 import java.util.concurrent.TimeUnit.MILLISECONDS
-import scala.reflect.ClassTag
-import akka.serialization.{ JavaSerializer, SerializationExtension }
 import java.io.ObjectStreamException
-import scala.util.{ Try, Success, Failure }
+import java.lang.reflect.{ InvocationTargetException, Method, InvocationHandler, Proxy }
-import scala.concurrent.duration.FiniteDuration
 
 /**
  * A TypedActorFactory is something that can created TypedActor instances.
@@ -439,8 +442,8 @@ object TypedProps {
    * @return a sequence of interfaces that the specified class implements,
    * or a sequence containing only itself, if itself is an interface.
    */
-  def extractInterfaces(clazz: Class[_]): Seq[Class[_]] =
+  def extractInterfaces(clazz: Class[_]): immutable.Seq[Class[_]] =
-    if (clazz.isInterface) Seq[Class[_]](clazz) else clazz.getInterfaces.toList
+    if (clazz.isInterface) immutableSingletonSeq(clazz) else immutableSeq(clazz.getInterfaces)
 
   /**
    * Uses the supplied class as the factory for the TypedActor implementation,
@@ -489,7 +492,7 @@ object TypedProps {
  */
 @SerialVersionUID(1L)
 case class TypedProps[T <: AnyRef] protected[TypedProps] (
-  interfaces: Seq[Class[_]],
+  interfaces: immutable.Seq[Class[_]],
   creator: () ⇒ T,
   dispatcher: String = TypedProps.defaultDispatcherId,
   deploy: Deploy = Props.defaultDeploy,

akka-actor/src/main/scala/akka/actor/dsl/Creators.scala

@@ -29,7 +29,9 @@ trait Creators { this: ActorDSL.type ⇒
    * for quickly trying things out in the REPL. It makes the following keywords
    * available:
    *
-   *  - `become` mapped to `context.become(_, discardOld = false)`
+   *  - `become` mapped to `context.become(_, discardOld = true)`
+   *
+   *  - `becomeStacked` mapped to `context.become(_, discardOld = false)`
    *
    *  - `unbecome` mapped to `context.unbecome`
    *
@@ -87,7 +89,14 @@ trait Creators { this: ActorDSL.type ⇒
      * stack is cleared upon restart. Use `unbecome()` to pop an element off
      * this stack.
      */
-    def become(r: Receive) = context.become(r, discardOld = false)
+    def becomeStacked(r: Receive) = context.become(r, discardOld = false)
+
+    /**
+     * Replace the behavior at the top of the behavior stack for this actor. The
+     * stack is cleared upon restart. Use `unbecome()` to pop an element off
+     * this stack or `becomeStacked()` to push a new element on top of it.
+     */
+    def become(r: Receive) = context.become(r, discardOld = true)
 
     /**
      * Pop the active behavior from the behavior stack of this actor. This stack

akka-actor/src/main/scala/akka/actor/dungeon/Children.scala

@@ -5,14 +5,12 @@
 package akka.actor.dungeon
 
 import scala.annotation.tailrec
-import scala.collection.JavaConverters.asJavaIterableConverter
 import scala.util.control.NonFatal
+import scala.collection.immutable
 import akka.actor._
-import akka.actor.ActorCell
 import akka.actor.ActorPath.ElementRegex
 import akka.serialization.SerializationExtension
 import akka.util.{ Unsafe, Helpers }
-import akka.actor.ChildNameReserved
 
 private[akka] trait Children { this: ActorCell ⇒
 
@@ -24,8 +22,9 @@ private[akka] trait Children { this: ActorCell ⇒
   def childrenRefs: ChildrenContainer =
     Unsafe.instance.getObjectVolatile(this, AbstractActorCell.childrenOffset).asInstanceOf[ChildrenContainer]
 
-  final def children: Iterable[ActorRef] = childrenRefs.children
+  final def children: immutable.Iterable[ActorRef] = childrenRefs.children
-  final def getChildren(): java.lang.Iterable[ActorRef] = children.asJava
+  final def getChildren(): java.lang.Iterable[ActorRef] =
+    scala.collection.JavaConverters.asJavaIterableConverter(children).asJava
 
   final def child(name: String): Option[ActorRef] = Option(getChild(name))
   final def getChild(name: String): ActorRef = childrenRefs.getByName(name) match {
@@ -141,7 +140,7 @@ private[akka] trait Children { this: ActorCell ⇒
 
   protected def getChildByRef(ref: ActorRef): Option[ChildRestartStats] = childrenRefs.getByRef(ref)
 
-  protected def getAllChildStats: Iterable[ChildRestartStats] = childrenRefs.stats
+  protected def getAllChildStats: immutable.Iterable[ChildRestartStats] = childrenRefs.stats
 
   protected def removeChildAndGetStateChange(child: ActorRef): Option[SuspendReason] = {
     childrenRefs match {

akka-actor/src/main/scala/akka/actor/dungeon/ChildrenContainer.scala

@@ -4,10 +4,11 @@
 
 package akka.actor.dungeon
 
-import scala.collection.immutable.TreeMap
+import scala.collection.immutable
 
 import akka.actor.{ InvalidActorNameException, ChildStats, ChildRestartStats, ChildNameReserved, ActorRef }
 import akka.dispatch.SystemMessage
+import akka.util.Collections.{ EmptyImmutableSeq, PartialImmutableValuesIterable }
 
 /**
  * INTERNAL API
@@ -20,8 +21,8 @@ private[akka] trait ChildrenContainer {
   def getByName(name: String): Option[ChildStats]
   def getByRef(actor: ActorRef): Option[ChildRestartStats]
 
-  def children: Iterable[ActorRef]
+  def children: immutable.Iterable[ActorRef]
-  def stats: Iterable[ChildRestartStats]
+  def stats: immutable.Iterable[ChildRestartStats]
 
   def shallDie(actor: ActorRef): ChildrenContainer
 
@@ -49,6 +50,18 @@ private[akka] object ChildrenContainer {
   case class Creation() extends SuspendReason with WaitingForChildren
   case object Termination extends SuspendReason
 
+  class ChildRestartsIterable(stats: immutable.MapLike[_, ChildStats, _]) extends PartialImmutableValuesIterable[ChildStats, ChildRestartStats] {
+    override final def apply(c: ChildStats) = c.asInstanceOf[ChildRestartStats]
+    override final def isDefinedAt(c: ChildStats) = c.isInstanceOf[ChildRestartStats]
+    override final def valuesIterator = stats.valuesIterator
+  }
+
+  class ChildrenIterable(stats: immutable.MapLike[_, ChildStats, _]) extends PartialImmutableValuesIterable[ChildStats, ActorRef] {
+    override final def apply(c: ChildStats) = c.asInstanceOf[ChildRestartStats].child
+    override final def isDefinedAt(c: ChildStats) = c.isInstanceOf[ChildRestartStats]
+    override final def valuesIterator = stats.valuesIterator
+  }
+
   trait WaitingForChildren {
     private var todo: SystemMessage = null
     def enqueue(message: SystemMessage) = { message.next = todo; todo = message }
@@ -56,13 +69,13 @@ private[akka] object ChildrenContainer {
   }
 
   trait EmptyChildrenContainer extends ChildrenContainer {
-    val emptyStats = TreeMap.empty[String, ChildStats]
+    val emptyStats = immutable.TreeMap.empty[String, ChildStats]
     override def add(name: String, stats: ChildRestartStats): ChildrenContainer = new NormalChildrenContainer(emptyStats.updated(name, stats))
     override def remove(child: ActorRef): ChildrenContainer = this
     override def getByName(name: String): Option[ChildRestartStats] = None
     override def getByRef(actor: ActorRef): Option[ChildRestartStats] = None
-    override def children: Iterable[ActorRef] = Nil
+    override def children: immutable.Iterable[ActorRef] = EmptyImmutableSeq
-    override def stats: Iterable[ChildRestartStats] = Nil
+    override def stats: immutable.Iterable[ChildRestartStats] = EmptyImmutableSeq
     override def shallDie(actor: ActorRef): ChildrenContainer = this
     override def reserve(name: String): ChildrenContainer = new NormalChildrenContainer(emptyStats.updated(name, ChildNameReserved))
     override def unreserve(name: String): ChildrenContainer = this
@@ -95,7 +108,7 @@ private[akka] object ChildrenContainer {
    * calling context.stop(child) and processing the ChildTerminated() system
    * message).
    */
-  class NormalChildrenContainer(val c: TreeMap[String, ChildStats]) extends ChildrenContainer {
+  class NormalChildrenContainer(val c: immutable.TreeMap[String, ChildStats]) extends ChildrenContainer {
 
     override def add(name: String, stats: ChildRestartStats): ChildrenContainer = new NormalChildrenContainer(c.updated(name, stats))
 
@@ -108,9 +121,11 @@ private[akka] object ChildrenContainer {
       case _ ⇒ None
     }
 
-    override def children: Iterable[ActorRef] = c.values.view.collect { case ChildRestartStats(child, _, _) ⇒ child }
+    override def children: immutable.Iterable[ActorRef] =
+      if (c.isEmpty) EmptyImmutableSeq else new ChildrenIterable(c)
 
-    override def stats: Iterable[ChildRestartStats] = c.values.view.collect { case c: ChildRestartStats ⇒ c }
+    override def stats: immutable.Iterable[ChildRestartStats] =
+      if (c.isEmpty) EmptyImmutableSeq else new ChildRestartsIterable(c)
 
     override def shallDie(actor: ActorRef): ChildrenContainer = TerminatingChildrenContainer(c, Set(actor), UserRequest)
 
@@ -130,7 +145,7 @@ private[akka] object ChildrenContainer {
   }
 
   object NormalChildrenContainer {
-    def apply(c: TreeMap[String, ChildStats]): ChildrenContainer =
+    def apply(c: immutable.TreeMap[String, ChildStats]): ChildrenContainer =
       if (c.isEmpty) EmptyChildrenContainer
       else new NormalChildrenContainer(c)
   }
@@ -145,7 +160,7 @@ private[akka] object ChildrenContainer {
    * type of container, depending on whether or not children are left and whether or not
    * the reason was “Terminating”.
    */
-  case class TerminatingChildrenContainer(c: TreeMap[String, ChildStats], toDie: Set[ActorRef], reason: SuspendReason)
+  case class TerminatingChildrenContainer(c: immutable.TreeMap[String, ChildStats], toDie: Set[ActorRef], reason: SuspendReason)
     extends ChildrenContainer {
 
     override def add(name: String, stats: ChildRestartStats): ChildrenContainer = copy(c.updated(name, stats))
@@ -166,9 +181,11 @@ private[akka] object ChildrenContainer {
       case _ ⇒ None
     }
 
-    override def children: Iterable[ActorRef] = c.values.view.collect { case ChildRestartStats(child, _, _) ⇒ child }
+    override def children: immutable.Iterable[ActorRef] =
+      if (c.isEmpty) EmptyImmutableSeq else new ChildrenIterable(c)
 
-    override def stats: Iterable[ChildRestartStats] = c.values.view.collect { case c: ChildRestartStats ⇒ c }
+    override def stats: immutable.Iterable[ChildRestartStats] =
+      if (c.isEmpty) EmptyImmutableSeq else new ChildRestartsIterable(c)
 
     override def shallDie(actor: ActorRef): ChildrenContainer = copy(toDie = toDie + actor)
 

akka-actor/src/main/scala/akka/actor/dungeon/FaultHandling.scala

@@ -10,7 +10,7 @@ import akka.dispatch._
 import akka.event.Logging.{ Warning, Error, Debug }
 import scala.util.control.NonFatal
 import akka.event.Logging
-import scala.Some
+import scala.collection.immutable
 import akka.dispatch.ChildTerminated
 import akka.actor.PreRestartException
 import akka.actor.Failed
@@ -160,7 +160,7 @@ private[akka] trait FaultHandling { this: ActorCell ⇒
     }
   }
 
-  final def handleInvokeFailure(childrenNotToSuspend: Iterable[ActorRef], t: Throwable, message: String): Unit = {
+  final def handleInvokeFailure(childrenNotToSuspend: immutable.Iterable[ActorRef], t: Throwable, message: String): Unit = {
     publish(Error(t, self.path.toString, clazz(actor), message))
     // prevent any further messages to be processed until the actor has been restarted
     if (!isFailed) try {

akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala

@@ -420,7 +420,7 @@ abstract class MessageDispatcherConfigurator(val config: Config, val prerequisit
       case "unbounded" ⇒ UnboundedMailbox()
       case "bounded"   ⇒ new BoundedMailbox(prerequisites.settings, config)
       case fqcn ⇒
-        val args = Seq(classOf[ActorSystem.Settings] -> prerequisites.settings, classOf[Config] -> config)
+        val args = List(classOf[ActorSystem.Settings] -> prerequisites.settings, classOf[Config] -> config)
         prerequisites.dynamicAccess.createInstanceFor[MailboxType](fqcn, args).recover({
           case exception ⇒
             throw new IllegalArgumentException(
@@ -436,7 +436,7 @@ abstract class MessageDispatcherConfigurator(val config: Config, val prerequisit
       case null | "" | "fork-join-executor" ⇒ new ForkJoinExecutorConfigurator(config.getConfig("fork-join-executor"), prerequisites)
       case "thread-pool-executor"           ⇒ new ThreadPoolExecutorConfigurator(config.getConfig("thread-pool-executor"), prerequisites)
       case fqcn ⇒
-        val args = Seq(
+        val args = List(
           classOf[Config] -> config,
           classOf[DispatcherPrerequisites] -> prerequisites)
         prerequisites.dynamicAccess.createInstanceFor[ExecutorServiceConfigurator](fqcn, args).recover({

akka-actor/src/main/scala/akka/dispatch/Dispatchers.scala

@@ -147,7 +147,7 @@ class Dispatchers(val settings: ActorSystem.Settings, val prerequisites: Dispatc
       case "BalancingDispatcher" ⇒ new BalancingDispatcherConfigurator(cfg, prerequisites)
       case "PinnedDispatcher"    ⇒ new PinnedDispatcherConfigurator(cfg, prerequisites)
       case fqn ⇒
-        val args = Seq(classOf[Config] -> cfg, classOf[DispatcherPrerequisites] -> prerequisites)
+        val args = List(classOf[Config] -> cfg, classOf[DispatcherPrerequisites] -> prerequisites)
         prerequisites.dynamicAccess.createInstanceFor[MessageDispatcherConfigurator](fqn, args).recover({
           case exception ⇒
             throw new IllegalArgumentException(

akka-actor/src/main/scala/akka/dispatch/Future.scala

@@ -95,7 +95,7 @@ object Futures {
    */
   def find[T <: AnyRef](futures: JIterable[Future[T]], predicate: JFunc[T, java.lang.Boolean], executor: ExecutionContext): Future[JOption[T]] = {
     implicit val ec = executor
-    Future.find[T](futures.asScala)(predicate.apply(_))(executor).map(JOption.fromScalaOption(_))
+    Future.find[T](futures.asScala)(predicate.apply(_))(executor) map JOption.fromScalaOption
   }
 
   /**

akka-actor/src/main/scala/akka/event/EventBus.scala

@@ -10,6 +10,7 @@ import java.util.concurrent.ConcurrentSkipListSet
 import java.util.Comparator
 import akka.util.{ Subclassification, SubclassifiedIndex }
 import scala.collection.immutable.TreeSet
+import scala.collection.immutable
 
 /**
  * Represents the base type for EventBuses
@@ -167,12 +168,12 @@ trait SubchannelClassification { this: EventBus ⇒
     recv foreach (publish(event, _))
   }
 
-  private def removeFromCache(changes: Seq[(Classifier, Set[Subscriber])]): Unit =
+  private def removeFromCache(changes: immutable.Seq[(Classifier, Set[Subscriber])]): Unit =
     cache = (cache /: changes) {
       case (m, (c, cs)) ⇒ m.updated(c, m.getOrElse(c, Set.empty[Subscriber]) -- cs)
     }
 
-  private def addToCache(changes: Seq[(Classifier, Set[Subscriber])]): Unit =
+  private def addToCache(changes: immutable.Seq[(Classifier, Set[Subscriber])]): Unit =
     cache = (cache /: changes) {
       case (m, (c, cs)) ⇒ m.updated(c, m.getOrElse(c, Set.empty[Subscriber]) ++ cs)
     }
@@ -265,9 +266,9 @@ trait ActorClassification { this: ActorEventBus with ActorClassifier ⇒
     }
   }
 
-  protected final def dissociate(monitored: ActorRef): Iterable[ActorRef] = {
+  protected final def dissociate(monitored: ActorRef): immutable.Iterable[ActorRef] = {
     @tailrec
-    def dissociateAsMonitored(monitored: ActorRef): Iterable[ActorRef] = {
+    def dissociateAsMonitored(monitored: ActorRef): immutable.Iterable[ActorRef] = {
       val current = mappings get monitored
       current match {
         case null ⇒ empty

akka-actor/src/main/scala/akka/event/Logging.scala

@@ -9,12 +9,13 @@ import akka.actor._
 import akka.{ ConfigurationException, AkkaException }
 import akka.actor.ActorSystem.Settings
 import akka.util.{ Timeout, ReentrantGuard }
-import scala.concurrent.duration._
 import java.util.concurrent.atomic.AtomicInteger
-import scala.util.control.NoStackTrace
 import java.util.concurrent.TimeoutException
+import scala.annotation.implicitNotFound
+import scala.collection.immutable
+import scala.concurrent.duration._
 import scala.concurrent.Await
-import annotation.implicitNotFound
+import scala.util.control.NoStackTrace
 
 /**
  * This trait brings log level handling to the EventStream: it reads the log
@@ -448,7 +449,7 @@ object Logging {
   }
 
   // these type ascriptions/casts are necessary to avoid CCEs during construction while retaining correct type
-  val AllLogLevels: Seq[LogLevel] = Seq(ErrorLevel, WarningLevel, InfoLevel, DebugLevel)
+  val AllLogLevels: immutable.Seq[LogLevel] = Vector(ErrorLevel, WarningLevel, InfoLevel, DebugLevel)
 
   /**
    * Obtain LoggingAdapter for the given actor system and source object. This
@@ -877,15 +878,25 @@ class BusLogging(val bus: LoggingBus, val logSource: String, val logClass: Class
   protected def notifyDebug(message: String): Unit = bus.publish(Debug(logSource, logClass, message))
 }
 
-private[akka] object NoLogging extends LoggingAdapter {
+/**
-  def isErrorEnabled = false
+ * NoLogging is a LoggingAdapter that does absolutely nothing – no logging at all.
-  def isWarningEnabled = false
+ */
-  def isInfoEnabled = false
+object NoLogging extends LoggingAdapter {
-  def isDebugEnabled = false
 
-  protected def notifyError(message: String): Unit = ()
+  /**
-  protected def notifyError(cause: Throwable, message: String): Unit = ()
+   * Java API to return the reference to NoLogging
-  protected def notifyWarning(message: String): Unit = ()
+   * @return The NoLogging instance
-  protected def notifyInfo(message: String): Unit = ()
+   */
-  protected def notifyDebug(message: String): Unit = ()
+  def getInstance = this
+
+  final override def isErrorEnabled = false
+  final override def isWarningEnabled = false
+  final override def isInfoEnabled = false
+  final override def isDebugEnabled = false
+
+  final protected override def notifyError(message: String): Unit = ()
+  final protected override def notifyError(cause: Throwable, message: String): Unit = ()
+  final protected override def notifyWarning(message: String): Unit = ()
+  final protected override def notifyInfo(message: String): Unit = ()
+  final protected override def notifyDebug(message: String): Unit = ()
 }

akka-actor/src/main/scala/akka/japi/JavaAPI.scala

@@ -5,10 +5,12 @@
 package akka.japi
 
 import language.implicitConversions
-import scala.Some
+
+import scala.collection.immutable
 import scala.reflect.ClassTag
 import scala.util.control.NoStackTrace
 import scala.runtime.AbstractPartialFunction
+import akka.util.Collections.EmptyImmutableSeq
 import java.util.Collections.{ emptyList, singletonList }
 
 /**
@@ -174,9 +176,40 @@ object Option {
  * This class hold common utilities for Java
  */
 object Util {
+
+  /**
+   * Returns a ClassTag describing the provided Class.
+   *
+   * Java API
+   */
   def classTag[T](clazz: Class[T]): ClassTag[T] = ClassTag(clazz)
 
-  def arrayToSeq[T](arr: Array[T]): Seq[T] = arr.toSeq
+  /**
+   * Returns an immutable.Seq representing the provided array of Classes,
+   * an overloading of the generic immutableSeq in Util, to accommodate for erasure.
+   *
+   * Java API
+   */
+  def immutableSeq(arr: Array[Class[_]]): immutable.Seq[Class[_]] = immutableSeq[Class[_]](arr)
 
-  def arrayToSeq(classes: Array[Class[_]]): Seq[Class[_]] = classes.toSeq
+  /**
+   *
+   */
+  def immutableSeq[T](arr: Array[T]): immutable.Seq[T] = if ((arr ne null) && arr.length > 0) Vector(arr: _*) else Nil
+
+  def immutableSeq[T](iterable: java.lang.Iterable[T]): immutable.Seq[T] =
+    iterable match {
+      case imm: immutable.Seq[_] ⇒ imm.asInstanceOf[immutable.Seq[T]]
+      case other ⇒
+        val i = other.iterator()
+        if (i.hasNext) {
+          val builder = new immutable.VectorBuilder[T]
+
+          do { builder += i.next() } while (i.hasNext)
+
+          builder.result()
+        } else EmptyImmutableSeq
+    }
+
+  def immutableSingletonSeq[T](value: T): immutable.Seq[T] = value :: Nil
 }

akka-actor/src/main/scala/akka/routing/ConsistentHash.scala

@@ -4,7 +4,7 @@
 
 package akka.routing
 
-import scala.collection.immutable.SortedMap
+import scala.collection.immutable
 import scala.reflect.ClassTag
 import java.util.Arrays
 
@@ -18,7 +18,7 @@ import java.util.Arrays
  * hash, i.e. make sure it is different for different nodes.
  *
  */
-class ConsistentHash[T: ClassTag] private (nodes: SortedMap[Int, T], val virtualNodesFactor: Int) {
+class ConsistentHash[T: ClassTag] private (nodes: immutable.SortedMap[Int, T], val virtualNodesFactor: Int) {
 
   import ConsistentHash._
 
@@ -106,7 +106,7 @@ class ConsistentHash[T: ClassTag] private (nodes: SortedMap[Int, T], val virtual
 
 object ConsistentHash {
   def apply[T: ClassTag](nodes: Iterable[T], virtualNodesFactor: Int): ConsistentHash[T] = {
-    new ConsistentHash(SortedMap.empty[Int, T] ++
+    new ConsistentHash(immutable.SortedMap.empty[Int, T] ++
       (for (node ← nodes; vnode ← 1 to virtualNodesFactor) yield (nodeHashFor(node, vnode) -> node)),
       virtualNodesFactor)
   }
@@ -120,8 +120,10 @@ object ConsistentHash {
     apply(nodes.asScala, virtualNodesFactor)(ClassTag(classOf[Any].asInstanceOf[Class[T]]))
   }
 
-  private def nodeHashFor(node: Any, vnode: Int): Int =
+  private def nodeHashFor(node: Any, vnode: Int): Int = {
-    hashFor((node + ":" + vnode).getBytes("UTF-8"))
+    val baseStr = node.toString + ":"
+    hashFor(baseStr + vnode)
+  }
 
   private def hashFor(bytes: Array[Byte]): Int = MurmurHash.arrayHash(bytes)
 

akka-actor/src/main/scala/akka/routing/ConsistentHashingRouter.scala

@@ -3,30 +3,29 @@
  */
 package akka.routing
 
-import scala.collection.JavaConverters.iterableAsScalaIterableConverter
+import scala.collection.immutable
+import akka.japi.Util.immutableSeq
 import scala.util.control.NonFatal
 import akka.actor.ActorRef
 import akka.actor.SupervisorStrategy
-import akka.actor.Props
 import akka.dispatch.Dispatchers
 import akka.event.Logging
 import akka.serialization.SerializationExtension
 import java.util.concurrent.atomic.AtomicReference
+import akka.actor.Address
+import akka.actor.ExtendedActorSystem
 
 object ConsistentHashingRouter {
   /**
    * Creates a new ConsistentHashingRouter, routing to the specified routees
    */
-  def apply(routees: Iterable[ActorRef]): ConsistentHashingRouter =
+  def apply(routees: immutable.Iterable[ActorRef]): ConsistentHashingRouter =
     new ConsistentHashingRouter(routees = routees map (_.path.toString))
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef]): ConsistentHashingRouter = {
+  def create(routees: java.lang.Iterable[ActorRef]): ConsistentHashingRouter = apply(immutableSeq(routees))
-    import scala.collection.JavaConverters._
-    apply(routees.asScala)
-  }
 
   /**
    * If you don't define the `hashMapping` when
@@ -144,7 +143,7 @@ object ConsistentHashingRouter {
  */
 @SerialVersionUID(1L)
 case class ConsistentHashingRouter(
-  nrOfInstances: Int = 0, routees: Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
+  nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
   val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
   val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy,
   val virtualNodesFactor: Int = 0,
@@ -163,7 +162,7 @@ case class ConsistentHashingRouter(
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String]) = this(routees = routeePaths.asScala)
+  def this(routeePaths: java.lang.Iterable[String]) = this(routees = immutableSeq(routeePaths))
 
   /**
    * Constructor that sets the resizer to be used.
@@ -225,7 +224,7 @@ trait ConsistentHashingLike { this: RouterConfig ⇒
 
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   def virtualNodesFactor: Int
 
@@ -238,20 +237,22 @@ trait ConsistentHashingLike { this: RouterConfig ⇒
     }
 
     val log = Logging(routeeProvider.context.system, routeeProvider.context.self)
+    val selfAddress = routeeProvider.context.system.asInstanceOf[ExtendedActorSystem].provider.rootPath.address
     val vnodes =
       if (virtualNodesFactor == 0) routeeProvider.context.system.settings.DefaultVirtualNodesFactor
       else virtualNodesFactor
 
     // tuple of routees and the ConsistentHash, updated together in updateConsistentHash
-    val consistentHashRef = new AtomicReference[(IndexedSeq[ActorRef], ConsistentHash[ActorRef])]((null, null))
+    val consistentHashRef = new AtomicReference[(IndexedSeq[ConsistentActorRef], ConsistentHash[ConsistentActorRef])]((null, null))
     updateConsistentHash()
 
     // update consistentHash when routees has changed
     // changes to routees are rare and when no changes this is a quick operation
-    def updateConsistentHash(): ConsistentHash[ActorRef] = {
+    def updateConsistentHash(): ConsistentHash[ConsistentActorRef] = {
       val oldConsistentHashTuple = consistentHashRef.get
       val (oldConsistentHashRoutees, oldConsistentHash) = oldConsistentHashTuple
-      val currentRoutees = routeeProvider.routees
+      val currentRoutees = routeeProvider.routees map { ConsistentActorRef(_, selfAddress) }
+
       if (currentRoutees ne oldConsistentHashRoutees) {
         // when other instance, same content, no need to re-hash, but try to set routees
         val consistentHash =
@@ -267,9 +268,9 @@ trait ConsistentHashingLike { this: RouterConfig ⇒
       val currentConsistenHash = updateConsistentHash()
       if (currentConsistenHash.isEmpty) routeeProvider.context.system.deadLetters
       else hashData match {
-        case bytes: Array[Byte] ⇒ currentConsistenHash.nodeFor(bytes)
+        case bytes: Array[Byte] ⇒ currentConsistenHash.nodeFor(bytes).actorRef
-        case str: String        ⇒ currentConsistenHash.nodeFor(str)
+        case str: String        ⇒ currentConsistenHash.nodeFor(str).actorRef
-        case x: AnyRef          ⇒ currentConsistenHash.nodeFor(SerializationExtension(routeeProvider.context.system).serialize(x).get)
+        case x: AnyRef          ⇒ currentConsistenHash.nodeFor(SerializationExtension(routeeProvider.context.system).serialize(x).get).actorRef
       }
     } catch {
       case NonFatal(e) ⇒
@@ -294,4 +295,21 @@ trait ConsistentHashingLike { this: RouterConfig ⇒
 
     }
   }
+}
+
+/**
+ * INTERNAL API
+ * Important to use ActorRef with full address, with host and port, in the hash ring,
+ * so that same ring is produced on different nodes.
+ * The ConsistentHash uses toString of the ring nodes, and the ActorRef itself
+ * isn't a good representation, because LocalActorRef doesn't include the
+ * host and port.
+ */
+private[akka] case class ConsistentActorRef(actorRef: ActorRef, selfAddress: Address) {
+  override def toString: String = {
+    actorRef.path.address match {
+      case Address(_, _, None, None) ⇒ actorRef.path.toStringWithAddress(selfAddress)
+      case a                         ⇒ actorRef.path.toString
+    }
+  }
 }

akka-actor/src/main/scala/akka/routing/Routing.scala

@@ -5,18 +5,20 @@ package akka.routing
 
 import language.implicitConversions
 import language.postfixOps
-import akka.actor._
+
-import scala.concurrent.duration._
+import scala.collection.immutable
-import akka.ConfigurationException
-import akka.pattern.pipe
-import com.typesafe.config.Config
 import scala.collection.JavaConverters.iterableAsScalaIterableConverter
+import scala.concurrent.duration._
+import akka.actor._
+import akka.ConfigurationException
+import akka.dispatch.Dispatchers
+import akka.pattern.pipe
+import akka.japi.Util.immutableSeq
+import com.typesafe.config.Config
 import java.util.concurrent.atomic.{ AtomicLong, AtomicBoolean }
 import java.util.concurrent.TimeUnit
 import scala.concurrent.forkjoin.ThreadLocalRandom
-import akka.dispatch.Dispatchers
 import scala.annotation.tailrec
-import concurrent.ExecutionContext
 
 /**
  * A RoutedActorRef is an ActorRef that has a set of connected ActorRef and it uses a Router to
@@ -50,7 +52,7 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
   private val resizeCounter = new AtomicLong
 
   @volatile
-  private var _routees: IndexedSeq[ActorRef] = IndexedSeq.empty[ActorRef] // this MUST be initialized during createRoute
+  private var _routees: immutable.IndexedSeq[ActorRef] = immutable.IndexedSeq.empty[ActorRef] // this MUST be initialized during createRoute
   def routees = _routees
 
   @volatile
@@ -75,14 +77,11 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
    * end of construction
    */
 
-  def applyRoute(sender: ActorRef, message: Any): Iterable[Destination] = message match {
+  def applyRoute(sender: ActorRef, message: Any): immutable.Iterable[Destination] = message match {
-    case _: AutoReceivedMessage ⇒ Destination(self, self) :: Nil
+    case _: AutoReceivedMessage                ⇒ Destination(self, self) :: Nil
-    case CurrentRoutees ⇒
+    case CurrentRoutees                        ⇒ sender ! RouterRoutees(_routees); Nil
-      sender ! RouterRoutees(_routees)
+    case msg if route.isDefinedAt(sender, msg) ⇒ route(sender, message)
-      Nil
+    case _                                     ⇒ Nil
-    case _ ⇒
-      if (route.isDefinedAt(sender, message)) route(sender, message)
-      else Nil
   }
 
   /**
@@ -91,7 +90,7 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
    * Not thread safe, but intended to be called from protected points, such as
    * `RouterConfig.createRoute` and `Resizer.resize`
    */
-  private[akka] def addRoutees(newRoutees: Iterable[ActorRef]): Unit = {
+  private[akka] def addRoutees(newRoutees: immutable.Iterable[ActorRef]): Unit = {
     _routees = _routees ++ newRoutees
     // subscribe to Terminated messages for all route destinations, to be handled by Router actor
     newRoutees foreach watch
@@ -103,7 +102,7 @@ private[akka] class RoutedActorCell(_system: ActorSystemImpl, _ref: InternalActo
    * Not thread safe, but intended to be called from protected points, such as
    * `Resizer.resize`
    */
-  private[akka] def removeRoutees(abandonedRoutees: Iterable[ActorRef]): Unit = {
+  private[akka] def removeRoutees(abandonedRoutees: immutable.Iterable[ActorRef]): Unit = {
     _routees = abandonedRoutees.foldLeft(_routees) { (xs, x) ⇒ unwatch(x); xs.filterNot(_ == x) }
   }
 
@@ -195,7 +194,7 @@ trait RouterConfig {
    */
   def withFallback(other: RouterConfig): RouterConfig = this
 
-  protected def toAll(sender: ActorRef, routees: Iterable[ActorRef]): Iterable[Destination] =
+  protected def toAll(sender: ActorRef, routees: immutable.Iterable[ActorRef]): immutable.Iterable[Destination] =
     routees.map(Destination(sender, _))
 
   /**
@@ -207,7 +206,7 @@ trait RouterConfig {
   /**
    * Check that everything is there which is needed. Called in constructor of RoutedActorRef to fail early.
    */
-  def verifyConfig(): Unit = {}
+  def verifyConfig(): Unit = ()
 
 }
 
@@ -226,7 +225,7 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
    * Not thread safe, but intended to be called from protected points, such as
    * `RouterConfig.createRoute` and `Resizer.resize`.
    */
-  def registerRoutees(routees: Iterable[ActorRef]): Unit = routedCell.addRoutees(routees)
+  def registerRoutees(routees: immutable.Iterable[ActorRef]): Unit = routedCell.addRoutees(routees)
 
   /**
    * Adds the routees to the router.
@@ -235,7 +234,7 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
    * `RouterConfig.createRoute` and `Resizer.resize`.
    * Java API.
    */
-  def registerRoutees(routees: java.lang.Iterable[ActorRef]): Unit = registerRoutees(routees.asScala)
+  def registerRoutees(routees: java.lang.Iterable[ActorRef]): Unit = registerRoutees(immutableSeq(routees))
 
   /**
    * Removes routees from the router. This method doesn't stop the routees.
@@ -243,7 +242,7 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
    * Not thread safe, but intended to be called from protected points, such as
    * `Resizer.resize`.
    */
-  def unregisterRoutees(routees: Iterable[ActorRef]): Unit = routedCell.removeRoutees(routees)
+  def unregisterRoutees(routees: immutable.Iterable[ActorRef]): Unit = routedCell.removeRoutees(routees)
 
   /**
    * Removes routees from the router. This method doesn't stop the routees.
@@ -252,28 +251,25 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
    * `Resizer.resize`.
    * JAVA API
    */
-  def unregisterRoutees(routees: java.lang.Iterable[ActorRef]): Unit = unregisterRoutees(routees.asScala)
+  def unregisterRoutees(routees: java.lang.Iterable[ActorRef]): Unit = unregisterRoutees(immutableSeq(routees))
 
   /**
    * Looks up routes with specified paths and registers them.
    */
-  def registerRouteesFor(paths: Iterable[String]): Unit = registerRoutees(paths.map(context.actorFor(_)))
+  def registerRouteesFor(paths: immutable.Iterable[String]): Unit = registerRoutees(paths.map(context.actorFor(_)))
 
   /**
    * Looks up routes with specified paths and registers them.
    * JAVA API
    */
-  def registerRouteesFor(paths: java.lang.Iterable[String]): Unit = registerRouteesFor(paths.asScala)
+  def registerRouteesFor(paths: java.lang.Iterable[String]): Unit = registerRouteesFor(immutableSeq(paths))
 
   /**
    * Creates new routees from specified `Props` and registers them.
    */
-  def createRoutees(nrOfInstances: Int): Unit = {
+  def createRoutees(nrOfInstances: Int): Unit =
-    if (nrOfInstances <= 0) throw new IllegalArgumentException(
+    if (nrOfInstances <= 0) throw new IllegalArgumentException("Must specify nrOfInstances or routees for [%s]" format context.self.path.toString)
-      "Must specify nrOfInstances or routees for [%s]" format context.self.path.toString)
+    else registerRoutees(immutable.IndexedSeq.fill(nrOfInstances)(context.actorOf(routeeProps)))
-    else
-      registerRoutees(IndexedSeq.fill(nrOfInstances)(context.actorOf(routeeProps)))
-  }
 
   /**
    * Remove specified number of routees by unregister them
@@ -296,7 +292,7 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
    * Give concurrent messages a chance to be placed in mailbox before
    * sending PoisonPill.
    */
-  protected def delayedStop(scheduler: Scheduler, abandon: Iterable[ActorRef], stopDelay: FiniteDuration): Unit = {
+  protected def delayedStop(scheduler: Scheduler, abandon: immutable.Iterable[ActorRef], stopDelay: FiniteDuration): Unit = {
     if (abandon.nonEmpty) {
       if (stopDelay <= Duration.Zero) {
         abandon foreach (_ ! PoisonPill)
@@ -314,7 +310,7 @@ class RouteeProvider(val context: ActorContext, val routeeProps: Props, val resi
   /**
    * All routees of the router
    */
-  def routees: IndexedSeq[ActorRef] = routedCell.routees
+  def routees: immutable.IndexedSeq[ActorRef] = routedCell.routees
 
   /**
    * All routees of the router
@@ -335,7 +331,7 @@ abstract class CustomRouterConfig extends RouterConfig {
     val customRoute = createCustomRoute(routeeProvider)
 
     {
-      case (sender, message) ⇒ customRoute.destinationsFor(sender, message).asScala
+      case (sender, message) ⇒ customRoute.destinationsFor(sender, message)
     }
   }
 
@@ -344,7 +340,13 @@ abstract class CustomRouterConfig extends RouterConfig {
 }
 
 trait CustomRoute {
-  def destinationsFor(sender: ActorRef, message: Any): java.lang.Iterable[Destination]
+  /**
+   * use akka.japi.Util.immutableSeq to convert a java.lang.Iterable to the return type needed for destinationsFor,
+   * or if you just want to return a single Destination, use akka.japi.Util.immutableSingletonSeq
+   *
+   * Java API
+   */
+  def destinationsFor(sender: ActorRef, message: Any): immutable.Seq[Destination]
 }
 
 /**
@@ -366,7 +368,7 @@ trait Router extends Actor {
       if (ab.get) try ref.routerConfig.resizer foreach (_.resize(ref.routeeProvider)) finally ab.set(false)
 
     case Terminated(child) ⇒
-      ref.removeRoutees(IndexedSeq(child))
+      ref.removeRoutees(child :: Nil)
       if (ref.routees.isEmpty) context.stop(self)
 
   }: Receive) orElse routerReceive
@@ -426,7 +428,7 @@ case object CurrentRoutees extends CurrentRoutees {
  * Message used to carry information about what routees the router is currently using.
  */
 @SerialVersionUID(1L)
-case class RouterRoutees(routees: Iterable[ActorRef])
+case class RouterRoutees(routees: immutable.Iterable[ActorRef])
 
 /**
  * For every message sent to a router, its route determines a set of destinations,
@@ -494,16 +496,14 @@ object RoundRobinRouter {
   /**
    * Creates a new RoundRobinRouter, routing to the specified routees
    */
-  def apply(routees: Iterable[ActorRef]): RoundRobinRouter =
+  def apply(routees: immutable.Iterable[ActorRef]): RoundRobinRouter =
     new RoundRobinRouter(routees = routees map (_.path.toString))
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef]): RoundRobinRouter = {
+  def create(routees: java.lang.Iterable[ActorRef]): RoundRobinRouter =
-    import scala.collection.JavaConverters._
+    apply(immutableSeq(routees))
-    apply(routees.asScala)
-  }
 }
 /**
  * A Router that uses round-robin to select a connection. For concurrent calls, round robin is just a best effort.
@@ -547,7 +547,7 @@ object RoundRobinRouter {
  *   using `actorFor` in [[akka.actor.ActorRefProvider]]
  */
 @SerialVersionUID(1L)
-case class RoundRobinRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
+case class RoundRobinRouter(nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
                             val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
                             val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy)
   extends RouterConfig with RoundRobinLike {
@@ -564,7 +564,7 @@ case class RoundRobinRouter(nrOfInstances: Int = 0, routees: Iterable[String] =
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String]) = this(routees = routeePaths.asScala)
+  def this(routeePaths: java.lang.Iterable[String]) = this(routees = immutableSeq(routeePaths))
 
   /**
    * Constructor that sets the resizer to be used.
@@ -602,7 +602,7 @@ trait RoundRobinLike { this: RouterConfig ⇒
 
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   def createRoute(routeeProvider: RouteeProvider): Route = {
     if (resizer.isEmpty) {
@@ -622,7 +622,7 @@ trait RoundRobinLike { this: RouterConfig ⇒
       case (sender, message) ⇒
         message match {
           case Broadcast(msg) ⇒ toAll(sender, routeeProvider.routees)
-          case msg            ⇒ List(Destination(sender, getNext()))
+          case msg            ⇒ Destination(sender, getNext()) :: Nil
         }
     }
   }
@@ -632,15 +632,13 @@ object RandomRouter {
   /**
    * Creates a new RandomRouter, routing to the specified routees
    */
-  def apply(routees: Iterable[ActorRef]): RandomRouter = new RandomRouter(routees = routees map (_.path.toString))
+  def apply(routees: immutable.Iterable[ActorRef]): RandomRouter = new RandomRouter(routees = routees map (_.path.toString))
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef]): RandomRouter = {
+  def create(routees: java.lang.Iterable[ActorRef]): RandomRouter =
-    import scala.collection.JavaConverters._
+    apply(immutableSeq(routees))
-    apply(routees.asScala)
-  }
 }
 /**
  * A Router that randomly selects one of the target connections to send a message to.
@@ -684,7 +682,7 @@ object RandomRouter {
  *   using `actorFor` in [[akka.actor.ActorRefProvider]]
  */
 @SerialVersionUID(1L)
-case class RandomRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
+case class RandomRouter(nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
                         val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
                         val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy)
   extends RouterConfig with RandomLike {
@@ -701,7 +699,7 @@ case class RandomRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil,
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String]) = this(routees = routeePaths.asScala)
+  def this(routeePaths: java.lang.Iterable[String]) = this(routees = immutableSeq(routeePaths))
 
   /**
    * Constructor that sets the resizer to be used.
@@ -738,7 +736,7 @@ case class RandomRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil,
 trait RandomLike { this: RouterConfig ⇒
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   def createRoute(routeeProvider: RouteeProvider): Route = {
     if (resizer.isEmpty) {
@@ -756,7 +754,7 @@ trait RandomLike { this: RouterConfig ⇒
       case (sender, message) ⇒
         message match {
           case Broadcast(msg) ⇒ toAll(sender, routeeProvider.routees)
-          case msg            ⇒ List(Destination(sender, getNext()))
+          case msg            ⇒ Destination(sender, getNext()) :: Nil
         }
     }
   }
@@ -766,16 +764,14 @@ object SmallestMailboxRouter {
   /**
    * Creates a new SmallestMailboxRouter, routing to the specified routees
    */
-  def apply(routees: Iterable[ActorRef]): SmallestMailboxRouter =
+  def apply(routees: immutable.Iterable[ActorRef]): SmallestMailboxRouter =
     new SmallestMailboxRouter(routees = routees map (_.path.toString))
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef]): SmallestMailboxRouter = {
+  def create(routees: java.lang.Iterable[ActorRef]): SmallestMailboxRouter =
-    import scala.collection.JavaConverters._
+    apply(immutableSeq(routees))
-    apply(routees.asScala)
-  }
 }
 /**
  * A Router that tries to send to the non-suspended routee with fewest messages in mailbox.
@@ -828,7 +824,7 @@ object SmallestMailboxRouter {
  *   using `actorFor` in [[akka.actor.ActorRefProvider]]
  */
 @SerialVersionUID(1L)
-case class SmallestMailboxRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
+case class SmallestMailboxRouter(nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
                                  val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
                                  val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy)
   extends RouterConfig with SmallestMailboxLike {
@@ -845,7 +841,7 @@ case class SmallestMailboxRouter(nrOfInstances: Int = 0, routees: Iterable[Strin
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String]) = this(routees = routeePaths.asScala)
+  def this(routeePaths: java.lang.Iterable[String]) = this(routees = immutableSeq(routeePaths))
 
   /**
    * Constructor that sets the resizer to be used.
@@ -882,7 +878,7 @@ case class SmallestMailboxRouter(nrOfInstances: Int = 0, routees: Iterable[Strin
 trait SmallestMailboxLike { this: RouterConfig ⇒
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   /**
    * Returns true if the actor is currently processing a message.
@@ -954,7 +950,7 @@ trait SmallestMailboxLike { this: RouterConfig ⇒
     // 4. An ActorRef with unknown mailbox size that isn't processing anything
     // 5. An ActorRef with a known mailbox size
     // 6. An ActorRef without any messages
-    @tailrec def getNext(targets: IndexedSeq[ActorRef] = routeeProvider.routees,
+    @tailrec def getNext(targets: immutable.IndexedSeq[ActorRef] = routeeProvider.routees,
                          proposedTarget: ActorRef = routeeProvider.context.system.deadLetters,
                          currentScore: Long = Long.MaxValue,
                          at: Int = 0,
@@ -985,7 +981,7 @@ trait SmallestMailboxLike { this: RouterConfig ⇒
       case (sender, message) ⇒
         message match {
           case Broadcast(msg) ⇒ toAll(sender, routeeProvider.routees)
-          case msg            ⇒ List(Destination(sender, getNext()))
+          case msg            ⇒ Destination(sender, getNext()) :: Nil
         }
     }
   }
@@ -995,15 +991,13 @@ object BroadcastRouter {
   /**
    * Creates a new BroadcastRouter, routing to the specified routees
    */
-  def apply(routees: Iterable[ActorRef]): BroadcastRouter = new BroadcastRouter(routees = routees map (_.path.toString))
+  def apply(routees: immutable.Iterable[ActorRef]): BroadcastRouter = new BroadcastRouter(routees = routees map (_.path.toString))
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef]): BroadcastRouter = {
+  def create(routees: java.lang.Iterable[ActorRef]): BroadcastRouter =
-    import scala.collection.JavaConverters._
+    apply(immutableSeq(routees))
-    apply(routees.asScala)
-  }
 }
 /**
  * A Router that uses broadcasts a message to all its connections.
@@ -1047,7 +1041,7 @@ object BroadcastRouter {
  *   using `actorFor` in [[akka.actor.ActorRefProvider]]
  */
 @SerialVersionUID(1L)
-case class BroadcastRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
+case class BroadcastRouter(nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, override val resizer: Option[Resizer] = None,
                            val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
                            val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy)
   extends RouterConfig with BroadcastLike {
@@ -1064,7 +1058,7 @@ case class BroadcastRouter(nrOfInstances: Int = 0, routees: Iterable[String] = N
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String]) = this(routees = routeePaths.asScala)
+  def this(routeePaths: java.lang.Iterable[String]) = this(routees = immutableSeq(routeePaths))
 
   /**
    * Constructor that sets the resizer to be used.
@@ -1102,7 +1096,7 @@ trait BroadcastLike { this: RouterConfig ⇒
 
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   def createRoute(routeeProvider: RouteeProvider): Route = {
     if (resizer.isEmpty) {
@@ -1120,16 +1114,14 @@ object ScatterGatherFirstCompletedRouter {
   /**
    * Creates a new ScatterGatherFirstCompletedRouter, routing to the specified routees, timing out after the specified Duration
    */
-  def apply(routees: Iterable[ActorRef], within: FiniteDuration): ScatterGatherFirstCompletedRouter =
+  def apply(routees: immutable.Iterable[ActorRef], within: FiniteDuration): ScatterGatherFirstCompletedRouter =
     new ScatterGatherFirstCompletedRouter(routees = routees map (_.path.toString), within = within)
 
   /**
    * Java API to create router with the supplied 'routees' actors.
    */
-  def create(routees: java.lang.Iterable[ActorRef], within: FiniteDuration): ScatterGatherFirstCompletedRouter = {
+  def create(routees: java.lang.Iterable[ActorRef], within: FiniteDuration): ScatterGatherFirstCompletedRouter =
-    import scala.collection.JavaConverters._
+    apply(immutableSeq(routees), within)
-    apply(routees.asScala, within)
-  }
 }
 /**
  * Simple router that broadcasts the message to all routees, and replies with the first response.
@@ -1175,7 +1167,7 @@ object ScatterGatherFirstCompletedRouter {
  *   using `actorFor` in [[akka.actor.ActorRefProvider]]
  */
 @SerialVersionUID(1L)
-case class ScatterGatherFirstCompletedRouter(nrOfInstances: Int = 0, routees: Iterable[String] = Nil, within: FiniteDuration,
+case class ScatterGatherFirstCompletedRouter(nrOfInstances: Int = 0, routees: immutable.Iterable[String] = Nil, within: FiniteDuration,
                                              override val resizer: Option[Resizer] = None,
                                              val routerDispatcher: String = Dispatchers.DefaultDispatcherId,
                                              val supervisorStrategy: SupervisorStrategy = Router.defaultSupervisorStrategy)
@@ -1196,7 +1188,7 @@ case class ScatterGatherFirstCompletedRouter(nrOfInstances: Int = 0, routees: It
    * @param routeePaths string representation of the actor paths of the routees that will be looked up
    *   using `actorFor` in [[akka.actor.ActorRefProvider]]
    */
-  def this(routeePaths: java.lang.Iterable[String], w: FiniteDuration) = this(routees = routeePaths.asScala, within = w)
+  def this(routeePaths: java.lang.Iterable[String], w: FiniteDuration) = this(routees = immutableSeq(routeePaths), within = w)
 
   /**
    * Constructor that sets the resizer to be used.
@@ -1234,7 +1226,7 @@ trait ScatterGatherFirstCompletedLike { this: RouterConfig ⇒
 
   def nrOfInstances: Int
 
-  def routees: Iterable[String]
+  def routees: immutable.Iterable[String]
 
   def within: FiniteDuration
 
@@ -1394,7 +1386,7 @@ case class DefaultResizer(
    * @param routees The current actor in the resizer
    * @return the number of routees by which the resizer should be adjusted (positive, negative or zero)
    */
-  def capacity(routees: IndexedSeq[ActorRef]): Int = {
+  def capacity(routees: immutable.IndexedSeq[ActorRef]): Int = {
     val currentSize = routees.size
     val press = pressure(routees)
     val delta = filter(press, currentSize)
@@ -1422,7 +1414,7 @@ case class DefaultResizer(
    * @param routees the current resizer of routees
    * @return number of busy routees, between 0 and routees.size
    */
-  def pressure(routees: IndexedSeq[ActorRef]): Int = {
+  def pressure(routees: immutable.IndexedSeq[ActorRef]): Int = {
     routees count {
       case a: ActorRefWithCell ⇒
         a.underlying match {

akka-actor/src/main/scala/akka/routing/package.scala

@@ -4,10 +4,12 @@
 
 package akka
 
+import scala.collection.immutable
+
 package object routing {
   /**
    * Routing logic, partial function from (sender, message) to a
    * set of destinations.
    */
-  type Route = PartialFunction[(akka.actor.ActorRef, Any), Iterable[Destination]]
+  type Route = PartialFunction[(akka.actor.ActorRef, Any), immutable.Iterable[Destination]]
 }

akka-actor/src/main/scala/akka/serialization/Serialization.scala

@@ -4,14 +4,14 @@
 
 package akka.serialization
 
-import akka.AkkaException
 import com.typesafe.config.Config
-import akka.actor.{ Extension, ExtendedActorSystem, Address, DynamicAccess }
+import akka.actor.{ Extension, ExtendedActorSystem, Address }
 import akka.event.Logging
 import java.util.concurrent.ConcurrentHashMap
 import scala.collection.mutable.ArrayBuffer
 import java.io.NotSerializableException
-import util.{ Try, DynamicVariable }
+import scala.util.{ Try, DynamicVariable }
+import scala.collection.immutable
 
 object Serialization {
 
@@ -27,17 +27,13 @@ object Serialization {
   val currentTransportAddress = new DynamicVariable[Address](null)
 
   class Settings(val config: Config) {
+    val Serializers: Map[String, String] = configToMap("akka.actor.serializers")
+    val SerializationBindings: Map[String, String] = configToMap("akka.actor.serialization-bindings")
 
-    import scala.collection.JavaConverters._
+    private final def configToMap(path: String): Map[String, String] = {
-    import config._
+      import scala.collection.JavaConverters._
-
+      config.getConfig(path).root.unwrapped.asScala.mapValues(_.toString).toMap
-    val Serializers: Map[String, String] = configToMap(getConfig("akka.actor.serializers"))
+    }
-
-    val SerializationBindings: Map[String, String] = configToMap(getConfig("akka.actor.serialization-bindings"))
-
-    private def configToMap(cfg: Config): Map[String, String] =
-      cfg.root.unwrapped.asScala.toMap.map { case (k, v) ⇒ (k, v.toString) }
-
   }
 }
 
@@ -62,16 +58,16 @@ class Serialization(val system: ExtendedActorSystem) extends Extension {
    * using the optional type hint to the Serializer and the optional ClassLoader ot load it into.
    * Returns either the resulting object or an Exception if one was thrown.
    */
-  def deserialize(bytes: Array[Byte],
+  def deserialize(bytes: Array[Byte], serializerId: Int, clazz: Option[Class[_]]): Try[AnyRef] =
-                  serializerId: Int,
+    Try(serializerByIdentity(serializerId).fromBinary(bytes, clazz))
-                  clazz: Option[Class[_]]): Try[AnyRef] = Try(serializerByIdentity(serializerId).fromBinary(bytes, clazz))
 
   /**
    * Deserializes the given array of bytes using the specified type to look up what Serializer should be used.
    * You can specify an optional ClassLoader to load the object into.
    * Returns either the resulting object or an Exception if one was thrown.
    */
-  def deserialize(bytes: Array[Byte], clazz: Class[_]): Try[AnyRef] = Try(serializerFor(clazz).fromBinary(bytes, Some(clazz)))
+  def deserialize(bytes: Array[Byte], clazz: Class[_]): Try[AnyRef] =
+    Try(serializerFor(clazz).fromBinary(bytes, Some(clazz)))
 
   /**
    * Returns the Serializer configured for the given object, returns the NullSerializer if it's null.
@@ -95,9 +91,8 @@ class Serialization(val system: ExtendedActorSystem) extends Extension {
    */
   def serializerFor(clazz: Class[_]): Serializer =
     serializerMap.get(clazz) match {
-      case null ⇒
+      case null ⇒ // bindings are ordered from most specific to least specific
-        // bindings are ordered from most specific to least specific
+        def unique(possibilities: immutable.Seq[(Class[_], Serializer)]): Boolean =
-        def unique(possibilities: Seq[(Class[_], Serializer)]): Boolean =
           possibilities.size == 1 ||
             (possibilities forall (_._1 isAssignableFrom possibilities(0)._1)) ||
             (possibilities forall (_._2 == possibilities(0)._2))
@@ -122,8 +117,8 @@ class Serialization(val system: ExtendedActorSystem) extends Extension {
    * loading is performed by the system’s [[akka.actor.DynamicAccess]].
    */
   def serializerOf(serializerFQN: String): Try[Serializer] =
-    system.dynamicAccess.createInstanceFor[Serializer](serializerFQN, Seq(classOf[ExtendedActorSystem] -> system)) recoverWith {
+    system.dynamicAccess.createInstanceFor[Serializer](serializerFQN, List(classOf[ExtendedActorSystem] -> system)) recoverWith {
-      case _ ⇒ system.dynamicAccess.createInstanceFor[Serializer](serializerFQN, Seq())
+      case _ ⇒ system.dynamicAccess.createInstanceFor[Serializer](serializerFQN, Nil)
     }
 
   /**
@@ -137,21 +132,21 @@ class Serialization(val system: ExtendedActorSystem) extends Extension {
    *  bindings is a Seq of tuple representing the mapping from Class to Serializer.
    *  It is primarily ordered by the most specific classes first, and secondly in the configured order.
    */
-  private[akka] val bindings: Seq[ClassSerializer] =
+  private[akka] val bindings: immutable.Seq[ClassSerializer] =
-    sort(for ((k: String, v: String) ← settings.SerializationBindings if v != "none") yield (system.dynamicAccess.getClassFor[Any](k).get, serializers(v)))
+    sort(for ((k: String, v: String) ← settings.SerializationBindings if v != "none") yield (system.dynamicAccess.getClassFor[Any](k).get, serializers(v))).to[immutable.Seq]
 
   /**
    * Sort so that subtypes always precede their supertypes, but without
    * obeying any order between unrelated subtypes (insert sort).
    */
-  private def sort(in: Iterable[ClassSerializer]): Seq[ClassSerializer] =
+  private def sort(in: Iterable[ClassSerializer]): immutable.Seq[ClassSerializer] =
-    (new ArrayBuffer[ClassSerializer](in.size) /: in) { (buf, ca) ⇒
+    ((new ArrayBuffer[ClassSerializer](in.size) /: in) { (buf, ca) ⇒
       buf.indexWhere(_._1 isAssignableFrom ca._1) match {
         case -1 ⇒ buf append ca
         case x  ⇒ buf insert (x, ca)
       }
       buf
-    }
+    }).to[immutable.Seq]
 
   /**
    * serializerMap is a Map whose keys is the class that is serializable and values is the serializer

akka-actor/src/main/scala/akka/util/Collections.scala

@@ -0,0 +1,54 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.util
+
+import scala.collection.immutable
+import scala.annotation.tailrec
+
+/**
+ * INTERNAL API
+ */
+private[akka] object Collections {
+
+  case object EmptyImmutableSeq extends immutable.Seq[Nothing] {
+    override final def iterator = Iterator.empty
+    override final def apply(idx: Int): Nothing = throw new java.lang.IndexOutOfBoundsException(idx.toString)
+    override final def length: Int = 0
+  }
+
+  abstract class PartialImmutableValuesIterable[From, To] extends immutable.Iterable[To] {
+    def isDefinedAt(from: From): Boolean
+    def apply(from: From): To
+    def valuesIterator: Iterator[From]
+    final def iterator: Iterator[To] = {
+      val superIterator = valuesIterator
+      new Iterator[To] {
+        private[this] var _next: To = _
+        private[this] var _hasNext = false
+
+        @tailrec override final def hasNext: Boolean =
+          if (!_hasNext && superIterator.hasNext) { // If we need and are able to look for the next value
+            val potentiallyNext = superIterator.next()
+            if (isDefinedAt(potentiallyNext)) {
+              _next = apply(potentiallyNext)
+              _hasNext = true
+              true
+            } else hasNext //Attempt to find the next
+          } else _hasNext // Return if we found one
+
+        override final def next(): To = if (hasNext) {
+          val ret = _next
+          _next = null.asInstanceOf[To] // Mark as consumed (nice to the GC, don't leak the last returned value)
+          _hasNext = false // Mark as consumed (we need to look for the next value)
+          ret
+        } else throw new java.util.NoSuchElementException("next")
+      }
+    }
+
+    override lazy val size: Int = iterator.size
+    override def foreach[C](f: To ⇒ C) = iterator foreach f
+  }
+
+}

akka-actor/src/main/scala/akka/util/Convert.scala

@@ -1,45 +0,0 @@
-/**
- *  Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
- */
-
-package akka.util
-//FIXME DOCS!
-object Convert {
-
-  def intToBytes(value: Int): Array[Byte] = {
-    val bytes = Array.fill[Byte](4)(0)
-    bytes(0) = (value >>> 24).asInstanceOf[Byte]
-    bytes(1) = (value >>> 16).asInstanceOf[Byte]
-    bytes(2) = (value >>> 8).asInstanceOf[Byte]
-    bytes(3) = value.asInstanceOf[Byte]
-    bytes
-  }
-
-  def bytesToInt(bytes: Array[Byte], offset: Int): Int = {
-    (0 until 4).foldLeft(0)((value, index) ⇒ value + ((bytes(index + offset) & 0x000000FF) << ((4 - 1 - index) * 8)))
-  }
-
-  def longToBytes(value: Long): Array[Byte] = {
-    val writeBuffer = Array.fill[Byte](8)(0)
-    writeBuffer(0) = (value >>> 56).asInstanceOf[Byte]
-    writeBuffer(1) = (value >>> 48).asInstanceOf[Byte]
-    writeBuffer(2) = (value >>> 40).asInstanceOf[Byte]
-    writeBuffer(3) = (value >>> 32).asInstanceOf[Byte]
-    writeBuffer(4) = (value >>> 24).asInstanceOf[Byte]
-    writeBuffer(5) = (value >>> 16).asInstanceOf[Byte]
-    writeBuffer(6) = (value >>> 8).asInstanceOf[Byte]
-    writeBuffer(7) = (value >>> 0).asInstanceOf[Byte]
-    writeBuffer
-  }
-
-  def bytesToLong(buf: Array[Byte]): Long = {
-    ((buf(0) & 0xFFL) << 56) |
-      ((buf(1) & 0xFFL) << 48) |
-      ((buf(2) & 0xFFL) << 40) |
-      ((buf(3) & 0xFFL) << 32) |
-      ((buf(4) & 0xFFL) << 24) |
-      ((buf(5) & 0xFFL) << 16) |
-      ((buf(6) & 0xFFL) << 8) |
-      ((buf(7) & 0xFFL) << 0)
-  }
-}

akka-actor/src/main/scala/akka/util/Index.scala

@@ -75,7 +75,7 @@ class Index[K, V](val mapSize: Int, val valueComparator: Comparator[V]) {
   def findValue(key: K)(f: (V) ⇒ Boolean): Option[V] =
     container get key match {
       case null ⇒ None
-      case set  ⇒ set.iterator.asScala.find(f)
+      case set  ⇒ set.iterator.asScala find f
     }
 
   /**

akka-actor/src/main/scala/akka/util/SubclassifiedIndex.scala

@@ -3,6 +3,8 @@
  */
 package akka.util
 
+import scala.collection.immutable
+
 /**
  * Typeclass which describes a classification hierarchy. Observe the contract between `isEqual` and `isSubclass`!
  */
@@ -55,7 +57,7 @@ private[akka] object SubclassifiedIndex {
   }
 
   private[SubclassifiedIndex] def emptyMergeMap[K, V] = internalEmptyMergeMap.asInstanceOf[Map[K, Set[V]]]
-  private[this] val internalEmptyMergeMap = Map[AnyRef, Set[AnyRef]]().withDefault(_ ⇒ Set[AnyRef]())
+  private[this] val internalEmptyMergeMap = Map[AnyRef, Set[AnyRef]]().withDefaultValue(Set[AnyRef]())
 }
 
 /**
@@ -74,7 +76,7 @@ private[akka] class SubclassifiedIndex[K, V] private (private var values: Set[V]
 
   import SubclassifiedIndex._
 
-  type Changes = Seq[(K, Set[V])]
+  type Changes = immutable.Seq[(K, Set[V])]
 
   protected var subkeys = Vector.empty[Nonroot[K, V]]
 
@@ -208,5 +210,5 @@ private[akka] class SubclassifiedIndex[K, V] private (private var values: Set[V]
   private def mergeChangesByKey(changes: Changes): Changes =
     (emptyMergeMap[K, V] /: changes) {
       case (m, (k, s)) ⇒ m.updated(k, m(k) ++ s)
-    }.toSeq
+    }.to[immutable.Seq]
 }

akka-actor/src/main/scala/akka/util/Unsafe.java

@@ -5,27 +5,9 @@
 
 package akka.util;
 
-import java.lang.reflect.Field;
-
 /**
  * INTERNAL API
  */
 public final class Unsafe {
-    public final static sun.misc.Unsafe instance;
+    public final static sun.misc.Unsafe instance = scala.concurrent.util.Unsafe.instance;
-    static {
-        try {
-            sun.misc.Unsafe found = null;
-            for(Field field : sun.misc.Unsafe.class.getDeclaredFields()) {
-              if (field.getType() == sun.misc.Unsafe.class) {
-                field.setAccessible(true);
-                found = (sun.misc.Unsafe) field.get(null);
-                break;
-              }
-            }
-            if (found == null) throw new IllegalStateException("Can't find instance of sun.misc.Unsafe");
-            else instance = found;
-        } catch(Throwable t) {
-          throw new ExceptionInInitializerError(t);
-        }
-    }
 }

akka-camel/src/main/scala/akka/camel/Camel.scala

@@ -4,16 +4,15 @@
 
 package akka.camel
 
-import internal._
+import akka.camel.internal._
 import akka.actor._
+import akka.ConfigurationException
 import org.apache.camel.ProducerTemplate
 import org.apache.camel.impl.DefaultCamelContext
 import org.apache.camel.model.RouteDefinition
 import com.typesafe.config.Config
-import akka.ConfigurationException
+import scala.concurrent.duration.{ Duration, FiniteDuration }
-import scala.concurrent.duration.Duration
 import java.util.concurrent.TimeUnit._
-import scala.concurrent.duration.FiniteDuration
 
 /**
  * Camel trait encapsulates the underlying camel machinery.
@@ -88,8 +87,8 @@ class CamelSettings private[camel] (config: Config, dynamicAccess: DynamicAccess
   final val StreamingCache: Boolean = config.getBoolean("akka.camel.streamingCache")
 
   final val Conversions: (String, RouteDefinition) ⇒ RouteDefinition = {
-    import scala.collection.JavaConverters.asScalaSetConverter
     val specifiedConversions = {
+      import scala.collection.JavaConverters.asScalaSetConverter
       val section = config.getConfig("akka.camel.conversions")
       section.entrySet.asScala.map(e ⇒ (e.getKey, section.getString(e.getKey)))
     }

akka-camel/src/test/scala/akka/camel/ConcurrentActivationTest.scala

@@ -1,13 +1,18 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
 package akka.camel
 
+import language.postfixOps
+
 import org.scalatest.WordSpec
 import org.scalatest.matchers.MustMatchers
+import scala.concurrent.{ Promise, Await, Future }
+import scala.collection.immutable
 import akka.camel.TestSupport.NonSharedCamelSystem
 import akka.actor.{ ActorRef, Props, Actor }
 import akka.routing.BroadcastRouter
-import concurrent.{ Promise, Await, Future }
 import scala.concurrent.duration._
-import language.postfixOps
 import akka.testkit._
 import akka.util.Timeout
 import org.apache.camel.model.RouteDefinition
@@ -58,7 +63,7 @@ class ConcurrentActivationTest extends WordSpec with MustMatchers with NonShared
         activations.size must be(2 * number * number)
         // must be the size of the activated activated producers and consumers
         deactivations.size must be(2 * number * number)
-        def partitionNames(refs: Seq[ActorRef]) = refs.map(_.path.name).partition(_.startsWith("concurrent-test-echo-consumer"))
+        def partitionNames(refs: immutable.Seq[ActorRef]) = refs.map(_.path.name).partition(_.startsWith("concurrent-test-echo-consumer"))
         def assertContainsSameElements(lists: (Seq[_], Seq[_])) {
           val (a, b) = lists
           a.intersect(b).size must be(a.size)

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -75,7 +75,7 @@ class Cluster(val system: ExtendedActorSystem) extends Extension {
   val failureDetector: FailureDetector = {
     import settings.{ FailureDetectorImplementationClass ⇒ fqcn }
     system.dynamicAccess.createInstanceFor[FailureDetector](
-      fqcn, Seq(classOf[ActorSystem] -> system, classOf[ClusterSettings] -> settings)).recover({
+      fqcn, List(classOf[ActorSystem] -> system, classOf[ClusterSettings] -> settings)).recover({
         case e ⇒ throw new ConfigurationException("Could not create custom failure detector [" + fqcn + "] due to:" + e.toString)
       }).get
   }

akka-cluster/src/main/scala/akka/cluster/ClusterMetricsCollector.scala

@@ -9,8 +9,8 @@ import scala.concurrent.duration._
 import scala.collection.immutable.{ SortedSet, Map }
 import scala.concurrent.forkjoin.ThreadLocalRandom
 import scala.util.{ Try, Success, Failure }
-import scala.math.ScalaNumericConversions
+import scala.math.ScalaNumericAnyConversions
-import scala.runtime.{ RichLong, RichDouble, RichInt }
+import runtime.{ ScalaNumberProxy, RichLong, RichDouble, RichInt }
 
 import akka.actor._
 import akka.event.LoggingAdapter
@@ -238,7 +238,7 @@ private[cluster] case class MetricsGossipEnvelope(from: Address, gossip: Metrics
  *
  * @param startTime the time of initial sampling for this data stream
  */
-private[cluster] case class DataStream(decay: Int, ewma: ScalaNumericConversions, startTime: Long, timestamp: Long)
+private[cluster] case class DataStream(decay: Int, ewma: ScalaNumericAnyConversions, startTime: Long, timestamp: Long)
   extends ClusterMessage with MetricNumericConverter {
 
   /**
@@ -249,13 +249,13 @@ private[cluster] case class DataStream(decay: Int, ewma: ScalaNumericConversions
 
   /**
    * Calculates the exponentially weighted moving average for a given monitored data set.
-   * The datam can be too large to fit into an int or long, thus we use ScalaNumericConversions,
+   * The datam can be too large to fit into an int or long, thus we use ScalaNumericAnyConversions,
    * and defer to BigInt or BigDecimal.
    *
    * @param xn the new data point
    * @return an new [[akka.cluster.DataStream]] with the updated yn and timestamp
    */
-  def :+(xn: ScalaNumericConversions): DataStream = convert(xn) fold (
+  def :+(xn: ScalaNumericAnyConversions): DataStream = convert(xn) fold (
     nl ⇒ copy(ewma = BigInt(α * nl + 1 - α * ewma.longValue()), timestamp = newTimestamp),
     nd ⇒ copy(ewma = BigDecimal(α * nd + 1 - α * ewma.doubleValue()), timestamp = newTimestamp))
 
@@ -273,7 +273,7 @@ private[cluster] case class DataStream(decay: Int, ewma: ScalaNumericConversions
  */
 private[cluster] object DataStream {
 
-  def apply(decay: Int, data: ScalaNumericConversions): Option[DataStream] = if (decay > 0)
+  def apply(decay: Int, data: ScalaNumericAnyConversions): Option[DataStream] = if (decay > 0)
     Some(DataStream(decay, data, newTimestamp, newTimestamp)) else None
 
 }
@@ -288,7 +288,7 @@ private[cluster] object DataStream {
  * @param average the data stream of the metric value, for trending over time. Metrics that are already
  *                averages (e.g. system load average) or finite (e.g. as total cores), are not trended.
  */
-private[cluster] case class Metric(name: String, value: Option[ScalaNumericConversions], average: Option[DataStream])
+private[cluster] case class Metric(name: String, value: Option[ScalaNumericAnyConversions], average: Option[DataStream])
   extends ClusterMessage with MetricNumericConverter {
 
   /**
@@ -352,7 +352,7 @@ private[cluster] object Metric extends MetricNumericConverter {
    * or defined for the OS (JMX). If undefined we set the value option to None and do not modify
    * the latest sampled metric to avoid skewing the statistical trend.
    */
-  def apply(name: String, value: Option[ScalaNumericConversions]): Metric = value match {
+  def apply(name: String, value: Option[ScalaNumericAnyConversions]): Metric = value match {
     case Some(v) if defined(v) ⇒ Metric(name, value, None)
     case _                     ⇒ Metric(name, None, None)
   }
@@ -409,13 +409,13 @@ private[cluster] trait MetricNumericConverter {
    * <ul><li>JMX system load average and max heap can be 'undefined' for certain OS, in which case a -1 is returned</li>
    * <li>SIGAR combined CPU can occasionally return a NaN or Infinite (known bug)</li></ul>
    */
-  def defined(value: ScalaNumericConversions): Boolean =
+  def defined(value: ScalaNumericAnyConversions): Boolean =
     convert(value) fold (a ⇒ value.underlying != -1, b ⇒ !(b.isNaN || b.isInfinite))
 
   /**
    * May involve rounding or truncation.
    */
-  def convert(from: ScalaNumericConversions): Either[Long, Double] = from match {
+  def convert(from: ScalaNumericAnyConversions): Either[Long, Double] = from match {
     case n: BigInt     ⇒ Left(n.longValue())
     case n: BigDecimal ⇒ Right(n.doubleValue())
     case n: RichInt    ⇒ Left(n.abs)
@@ -463,11 +463,16 @@ private[cluster] class MetricsCollector private (private val sigar: Option[AnyRe
 
   /**
    * (SIGAR / JMX) Returns the OS-specific average system load on the CPUs in the system, for the past 1 minute.
-   * On some systems the JMX OS system load average may not be available, in which case a -1 is returned.
+   * On some systems the JMX OS system load average may not be available, in which case a Metric with
+   * undefined value is returned.
    * Hyperic SIGAR provides more precise values, thus, if the library is on the classpath, it is the default.
    */
-  def systemLoadAverage: Metric = Metric("system-load-average", Some(BigDecimal(Try(
+  def systemLoadAverage: Metric = Metric("system-load-average",
-    LoadAverage.get.invoke(sigar.get).asInstanceOf[Array[Double]].toSeq.head) getOrElse osMBean.getSystemLoadAverage)))
+    Try(LoadAverage.get.invoke(sigar.get).asInstanceOf[Array[Double]].toSeq.head).getOrElse(
+      osMBean.getSystemLoadAverage) match {
+        case x if x < 0 ⇒ None // load average may be unavailable on some platform
+        case x          ⇒ Some(BigDecimal(x))
+      })
 
   /**
    * (JMX) Returns the number of available processors
@@ -552,7 +557,7 @@ private[cluster] class MetricsCollector private (private val sigar: Option[AnyRe
  */
 private[cluster] object MetricsCollector {
   def apply(address: Address, log: LoggingAdapter, dynamicAccess: DynamicAccess): MetricsCollector =
-    dynamicAccess.createInstanceFor[AnyRef]("org.hyperic.sigar.Sigar", Seq.empty) match {
+    dynamicAccess.createInstanceFor[AnyRef]("org.hyperic.sigar.Sigar", Nil) match {
       case Success(identity) ⇒ new MetricsCollector(Some(identity), address)
       case Failure(e) ⇒
         log.debug(e.toString)

akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala

@@ -45,9 +45,7 @@ class ClusterSettings(val config: Config, val systemName: String) {
     require(n > 0, "failure-detector.monitored-by-nr-of-members must be > 0"); n
   }
 
-  final val SeedNodes: IndexedSeq[Address] = getStringList("akka.cluster.seed-nodes").asScala.map {
+  final val SeedNodes: IndexedSeq[Address] = getStringList("akka.cluster.seed-nodes").asScala.map { case AddressFromURIString(addr) ⇒ addr }.toIndexedSeq
-    case AddressFromURIString(addr) ⇒ addr
-  }.toIndexedSeq
   final val SeedNodeTimeout: FiniteDuration = Duration(getMilliseconds("akka.cluster.seed-node-timeout"), MILLISECONDS)
   final val PeriodicTasksInitialDelay: FiniteDuration = Duration(getMilliseconds("akka.cluster.periodic-tasks-initial-delay"), MILLISECONDS)
   final val GossipInterval: FiniteDuration = Duration(getMilliseconds("akka.cluster.gossip-interval"), MILLISECONDS)

akka-cluster/src/main/scala/akka/cluster/routing/ClusterRouterConfig.scala

@@ -5,16 +5,13 @@ package akka.cluster.routing
 
 import java.lang.IllegalStateException
 import java.util.concurrent.atomic.AtomicInteger
-import scala.collection.immutable.SortedSet
+import scala.collection.immutable
 import com.typesafe.config.ConfigFactory
 import akka.ConfigurationException
-import akka.actor.Actor
 import akka.actor.ActorContext
 import akka.actor.ActorRef
-import akka.actor.ActorSystemImpl
 import akka.actor.Address
 import akka.actor.Deploy
-import akka.actor.InternalActorRef
 import akka.actor.Props
 import akka.actor.SupervisorStrategy
 import akka.cluster.Cluster
@@ -51,7 +48,7 @@ final case class ClusterRouterConfig(local: RouterConfig, settings: ClusterRoute
 
     // Intercept ClusterDomainEvent and route them to the ClusterRouterActor
     ({
-      case (sender, message: ClusterDomainEvent) ⇒ Seq(Destination(sender, routeeProvider.context.self))
+      case (sender, message: ClusterDomainEvent) ⇒ List(Destination(sender, routeeProvider.context.self))
     }: Route) orElse localRoute
   }
 
@@ -156,7 +153,7 @@ private[akka] class ClusterRouteeProvider(
   // need this counter as instance variable since Resizer may call createRoutees several times
   private val childNameCounter = new AtomicInteger
 
-  override def registerRouteesFor(paths: Iterable[String]): Unit =
+  override def registerRouteesFor(paths: immutable.Iterable[String]): Unit =
     throw new ConfigurationException("Cluster deployment can not be combined with routees for [%s]"
       format context.self.path.toString)
 
@@ -183,7 +180,7 @@ private[akka] class ClusterRouteeProvider(
             context.asInstanceOf[ActorCell].attachChild(routeeProps.withDeploy(deploy), name, systemService = false)
           }
         // must register each one, since registered routees are used in selectDeploymentTarget
-        registerRoutees(Some(ref))
+        registerRoutees(List(ref))
 
         // recursion until all created
         doCreateRoutees()
@@ -202,7 +199,7 @@ private[akka] class ClusterRouteeProvider(
     } else {
       // find the node with least routees
       val numberOfRouteesPerNode: Map[Address, Int] =
-        currentRoutees.foldLeft(currentNodes.map(_ -> 0).toMap.withDefault(_ ⇒ 0)) { (acc, x) ⇒
+        currentRoutees.foldLeft(currentNodes.map(_ -> 0).toMap.withDefaultValue(0)) { (acc, x) ⇒
           val address = fullAddress(x)
           acc + (address -> (acc(address) + 1))
         }
@@ -222,27 +219,26 @@ private[akka] class ClusterRouteeProvider(
     case a                         ⇒ a
   }
 
-  private[routing] def availableNodes: SortedSet[Address] = {
+  private[routing] def availableNodes: immutable.SortedSet[Address] = {
     import Member.addressOrdering
     val currentNodes = nodes
     if (currentNodes.isEmpty && settings.allowLocalRoutees)
       //use my own node, cluster information not updated yet
-      SortedSet(cluster.selfAddress)
+      immutable.SortedSet(cluster.selfAddress)
     else
       currentNodes
   }
 
   @volatile
-  private[routing] var nodes: SortedSet[Address] = {
+  private[routing] var nodes: immutable.SortedSet[Address] = {
     import Member.addressOrdering
     cluster.readView.members.collect {
       case m if isAvailable(m) ⇒ m.address
     }
   }
 
-  private[routing] def isAvailable(m: Member): Boolean = {
+  private[routing] def isAvailable(m: Member): Boolean =
     m.status == MemberStatus.Up && (settings.allowLocalRoutees || m.address != cluster.selfAddress)
-  }
 
 }
 

akka-cluster/src/multi-jvm/scala/akka/cluster/ClientDowningNodeThatIsUnreachableSpec.scala

@@ -8,6 +8,7 @@ import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
 import akka.actor.Address
+import scala.collection.immutable
 
 case class ClientDowningNodeThatIsUnreachableMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -51,7 +52,7 @@ abstract class ClientDowningNodeThatIsUnreachableSpec(multiNodeConfig: ClientDow
         cluster.down(thirdAddress)
         enterBarrier("down-third-node")
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(thirdAddress))
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(thirdAddress))
         clusterView.members.exists(_.address == thirdAddress) must be(false)
       }
 
@@ -62,7 +63,7 @@ abstract class ClientDowningNodeThatIsUnreachableSpec(multiNodeConfig: ClientDow
       runOn(second, fourth) {
         enterBarrier("down-third-node")
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(thirdAddress))
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(thirdAddress))
       }
 
       enterBarrier("await-completion")

akka-cluster/src/multi-jvm/scala/akka/cluster/ClientDowningNodeThatIsUpSpec.scala

@@ -8,6 +8,7 @@ import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
 import akka.actor.Address
+import scala.collection.immutable
 
 case class ClientDowningNodeThatIsUpMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -49,7 +50,7 @@ abstract class ClientDowningNodeThatIsUpSpec(multiNodeConfig: ClientDowningNodeT
 
         markNodeAsUnavailable(thirdAddress)
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(thirdAddress))
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(thirdAddress))
         clusterView.members.exists(_.address == thirdAddress) must be(false)
       }
 
@@ -60,7 +61,7 @@ abstract class ClientDowningNodeThatIsUpSpec(multiNodeConfig: ClientDowningNodeT
       runOn(second, fourth) {
         enterBarrier("down-third-node")
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(thirdAddress))
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(thirdAddress))
       }
 
       enterBarrier("await-completion")

akka-cluster/src/multi-jvm/scala/akka/cluster/LargeClusterSpec.scala

@@ -55,7 +55,6 @@ object LargeClusterMultiJvmSpec extends MultiNodeConfig {
     akka.remote.log-remote-lifecycle-events = off
     akka.remote.netty.execution-pool-size = 4
     #akka.remote.netty.reconnection-time-window = 10s
-    akka.remote.netty.read-timeout = 5s
     akka.remote.netty.write-timeout = 5s
     akka.remote.netty.backoff-timeout = 500ms
     akka.remote.netty.connection-timeout = 500ms
@@ -148,7 +147,7 @@ abstract class LargeClusterSpec
     runOn(runOnRoles: _*) {
       systems.size must be(nodesPerDatacenter) // make sure it is initialized
 
-      val clusterNodes = ifNode(from)(joiningClusterNodes)(systems.map(Cluster(_)).toSet)
+      val clusterNodes = if(isNode(from)) joiningClusterNodes else systems.map(Cluster(_)).toSet
       val startGossipCounts = Map.empty[Cluster, Long] ++
         clusterNodes.map(c ⇒ (c -> c.readView.latestStats.receivedGossipCount))
       def gossipCount(c: Cluster): Long = {
@@ -260,7 +259,7 @@ abstract class LargeClusterSpec
       if (bulk.nonEmpty) {
         val totalNodes = nodesPerDatacenter * 4 + bulk.size
         within(expectedMaxDuration(totalNodes)) {
-          val joiningClusters = ifNode(fifthDatacenter)(bulk.map(Cluster(_)).toSet)(Set.empty)
+          val joiningClusters = if(isNode(fifthDatacenter)) bulk.map(Cluster(_)).toSet else Set.empty[Cluster]
           join(joiningClusters, from = fifthDatacenter, to = firstDatacenter, totalNodes,
             runOnRoles = firstDatacenter, secondDatacenter, thirdDatacenter, fourthDatacenter, fifthDatacenter)
           enterBarrier("fifth-datacenter-joined-" + bulk.size)
@@ -270,7 +269,7 @@ abstract class LargeClusterSpec
       for (i ← 0 until oneByOne.size) {
         val totalNodes = nodesPerDatacenter * 4 + bulk.size + i + 1
         within(expectedMaxDuration(totalNodes)) {
-          val joiningClusters = ifNode(fifthDatacenter)(Set(Cluster(oneByOne(i))))(Set.empty)
+          val joiningClusters = if(isNode(fifthDatacenter)) Set(Cluster(oneByOne(i))) else Set.empty[Cluster]
           join(joiningClusters, from = fifthDatacenter, to = firstDatacenter, totalNodes,
             runOnRoles = firstDatacenter, secondDatacenter, thirdDatacenter, fourthDatacenter, fifthDatacenter)
           enterBarrier("fifth-datacenter-joined-" + (bulk.size + i))

akka-cluster/src/multi-jvm/scala/akka/cluster/LeaderDowningNodeThatIsUnreachableSpec.scala

@@ -11,6 +11,7 @@ import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
 import akka.actor._
 import scala.concurrent.duration._
+import scala.collection.immutable
 
 case class LeaderDowningNodeThatIsUnreachableMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -59,7 +60,7 @@ abstract class LeaderDowningNodeThatIsUnreachableSpec(multiNodeConfig: LeaderDow
 
         // --- HERE THE LEADER SHOULD DETECT FAILURE AND AUTO-DOWN THE UNREACHABLE NODE ---
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(fourthAddress), 30.seconds)
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(fourthAddress), 30.seconds)
       }
 
       runOn(fourth) {
@@ -69,7 +70,7 @@ abstract class LeaderDowningNodeThatIsUnreachableSpec(multiNodeConfig: LeaderDow
       runOn(second, third) {
         enterBarrier("down-fourth-node")
 
-        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = Seq(fourthAddress), 30.seconds)
+        awaitUpConvergence(numberOfMembers = 3, canNotBePartOfMemberRing = List(fourthAddress), 30.seconds)
       }
 
       enterBarrier("await-completion-1")
@@ -89,7 +90,7 @@ abstract class LeaderDowningNodeThatIsUnreachableSpec(multiNodeConfig: LeaderDow
 
         // --- HERE THE LEADER SHOULD DETECT FAILURE AND AUTO-DOWN THE UNREACHABLE NODE ---
 
-        awaitUpConvergence(numberOfMembers = 2, canNotBePartOfMemberRing = Seq(secondAddress), 30.seconds)
+        awaitUpConvergence(numberOfMembers = 2, canNotBePartOfMemberRing = List(secondAddress), 30.seconds)
       }
 
       runOn(second) {
@@ -99,7 +100,7 @@ abstract class LeaderDowningNodeThatIsUnreachableSpec(multiNodeConfig: LeaderDow
       runOn(third) {
         enterBarrier("down-second-node")
 
-        awaitUpConvergence(numberOfMembers = 2, canNotBePartOfMemberRing = Seq(secondAddress), 30 seconds)
+        awaitUpConvergence(numberOfMembers = 2, canNotBePartOfMemberRing = List(secondAddress), 30 seconds)
       }
 
       enterBarrier("await-completion-2")

akka-cluster/src/multi-jvm/scala/akka/cluster/LeaderElectionSpec.scala

@@ -10,6 +10,7 @@ import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
 import scala.concurrent.duration._
+import scala.collection.immutable
 
 case class LeaderElectionMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val controller = role("controller")
@@ -42,7 +43,7 @@ abstract class LeaderElectionSpec(multiNodeConfig: LeaderElectionMultiNodeConfig
   import multiNodeConfig._
 
   // sorted in the order used by the cluster
-  lazy val sortedRoles = Seq(first, second, third, fourth).sorted
+  lazy val sortedRoles = List(first, second, third, fourth).sorted
 
   "A cluster of four nodes" must {
 

akka-cluster/src/multi-jvm/scala/akka/cluster/MultiNodeClusterSpec.scala

@@ -4,21 +4,21 @@
 package akka.cluster
 
 import language.implicitConversions
+
+import org.scalatest.Suite
+import org.scalatest.exceptions.TestFailedException
+
 import com.typesafe.config.Config
 import com.typesafe.config.ConfigFactory
-import akka.actor.{ Address, ExtendedActorSystem }
 import akka.remote.testconductor.RoleName
 import akka.remote.testkit.{ STMultiNodeSpec, MultiNodeSpec }
 import akka.testkit._
 import akka.testkit.TestEvent._
-import scala.concurrent.duration._
+import akka.actor.{ ActorSystem, Address }
-import org.scalatest.Suite
-import org.scalatest.exceptions.TestFailedException
-import java.util.concurrent.ConcurrentHashMap
-import akka.actor.ActorPath
-import akka.actor.RootActorPath
 import akka.event.Logging.ErrorLevel
-import akka.actor.ActorSystem
+import scala.concurrent.duration._
+import scala.collection.immutable
+import java.util.concurrent.ConcurrentHashMap
 
 object MultiNodeClusterSpec {
 
@@ -158,7 +158,7 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec { self: MultiNodeS
    * nodes (roles). First node will be started first
    * and others will join the first.
    */
-  def startCluster(roles: RoleName*): Unit = awaitStartCluster(false, roles.toSeq)
+  def startCluster(roles: RoleName*): Unit = awaitStartCluster(false, roles.to[immutable.Seq])
 
   /**
    * Initialize the cluster of the specified member
@@ -166,11 +166,9 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec { self: MultiNodeS
    * First node will be started first  and others will join
    * the first.
    */
-  def awaitClusterUp(roles: RoleName*): Unit = {
+  def awaitClusterUp(roles: RoleName*): Unit = awaitStartCluster(true, roles.to[immutable.Seq])
-    awaitStartCluster(true, roles.toSeq)
-  }
 
-  private def awaitStartCluster(upConvergence: Boolean = true, roles: Seq[RoleName]): Unit = {
+  private def awaitStartCluster(upConvergence: Boolean = true, roles: immutable.Seq[RoleName]): Unit = {
     runOn(roles.head) {
       // make sure that the node-to-join is started before other join
       startClusterNode()
@@ -196,21 +194,20 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec { self: MultiNodeS
     expectedAddresses.sorted.zipWithIndex.foreach { case (a, i) ⇒ members(i).address must be(a) }
   }
 
-  def assertLeader(nodesInCluster: RoleName*): Unit = if (nodesInCluster.contains(myself)) {
+  def assertLeader(nodesInCluster: RoleName*): Unit =
-    assertLeaderIn(nodesInCluster)
+    if (nodesInCluster.contains(myself)) assertLeaderIn(nodesInCluster.to[immutable.Seq])
-  }
 
   /**
    * Assert that the cluster has elected the correct leader
    * out of all nodes in the cluster. First
    * member in the cluster ring is expected leader.
    */
-  def assertLeaderIn(nodesInCluster: Seq[RoleName]): Unit = if (nodesInCluster.contains(myself)) {
+  def assertLeaderIn(nodesInCluster: immutable.Seq[RoleName]): Unit = if (nodesInCluster.contains(myself)) {
     nodesInCluster.length must not be (0)
     val expectedLeader = roleOfLeader(nodesInCluster)
     val leader = clusterView.leader
     val isLeader = leader == Some(clusterView.selfAddress)
-    assert(isLeader == ifNode(expectedLeader)(true)(false),
+    assert(isLeader == isNode(expectedLeader),
       "expectedLeader [%s], got leader [%s], members [%s]".format(expectedLeader, leader, clusterView.members))
     clusterView.status must (be(MemberStatus.Up) or be(MemberStatus.Leaving))
   }
@@ -221,7 +218,7 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec { self: MultiNodeS
    */
   def awaitUpConvergence(
     numberOfMembers: Int,
-    canNotBePartOfMemberRing: Seq[Address] = Seq.empty[Address],
+    canNotBePartOfMemberRing: immutable.Seq[Address] = Nil,
     timeout: FiniteDuration = 20.seconds): Unit = {
     within(timeout) {
       awaitCond(clusterView.members.size == numberOfMembers)
@@ -239,7 +236,7 @@ trait MultiNodeClusterSpec extends Suite with STMultiNodeSpec { self: MultiNodeS
   def awaitSeenSameState(addresses: Address*): Unit =
     awaitCond((addresses.toSet -- clusterView.seenBy).isEmpty)
 
-  def roleOfLeader(nodesInCluster: Seq[RoleName] = roles): RoleName = {
+  def roleOfLeader(nodesInCluster: immutable.Seq[RoleName] = roles): RoleName = {
     nodesInCluster.length must not be (0)
     nodesInCluster.sorted.head
   }

akka-cluster/src/multi-jvm/scala/akka/cluster/SingletonClusterSpec.scala

@@ -8,6 +8,7 @@ import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
 import scala.concurrent.duration._
+import scala.collection.immutable
 
 case class SingletonClusterMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -65,7 +66,7 @@ abstract class SingletonClusterSpec(multiNodeConfig: SingletonClusterMultiNodeCo
 
         markNodeAsUnavailable(secondAddress)
 
-        awaitUpConvergence(numberOfMembers = 1, canNotBePartOfMemberRing = Seq(secondAddress), 30.seconds)
+        awaitUpConvergence(numberOfMembers = 1, canNotBePartOfMemberRing = List(secondAddress), 30.seconds)
         clusterView.isSingletonCluster must be(true)
         awaitCond(clusterView.isLeader)
       }

akka-cluster/src/multi-jvm/scala/akka/cluster/SplitBrainSpec.scala

@@ -9,9 +9,10 @@ import com.typesafe.config.ConfigFactory
 import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
-import scala.concurrent.duration._
 import akka.actor.Address
 import akka.remote.testconductor.Direction
+import scala.concurrent.duration._
+import scala.collection.immutable
 
 case class SplitBrainMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -53,8 +54,8 @@ abstract class SplitBrainSpec(multiNodeConfig: SplitBrainMultiNodeConfig)
 
   muteMarkingAsUnreachable()
 
-  val side1 = IndexedSeq(first, second)
+  val side1 = Vector(first, second)
-  val side2 = IndexedSeq(third, fourth, fifth)
+  val side2 = Vector(third, fourth, fifth)
 
   "A cluster of 5 members" must {
 

akka-cluster/src/multi-jvm/scala/akka/cluster/UnreachableNodeRejoinsClusterSpec.scala

@@ -6,13 +6,14 @@ package akka.cluster
 import language.postfixOps
 
 import org.scalatest.BeforeAndAfter
+import com.typesafe.config.ConfigFactory
 import akka.remote.testkit.MultiNodeConfig
 import akka.remote.testkit.MultiNodeSpec
 import akka.testkit._
-import com.typesafe.config.ConfigFactory
 import akka.actor.Address
 import akka.remote.testconductor.{ RoleName, Direction }
 import scala.concurrent.duration._
+import scala.collection.immutable
 
 case class UnreachableNodeRejoinsClusterMultiNodeConfig(failureDetectorPuppet: Boolean) extends MultiNodeConfig {
   val first = role("first")
@@ -45,7 +46,7 @@ abstract class UnreachableNodeRejoinsClusterSpec(multiNodeConfig: UnreachableNod
 
   muteMarkingAsUnreachable()
 
-  def allBut(role: RoleName, roles: Seq[RoleName] = roles): Seq[RoleName] = {
+  def allBut(role: RoleName, roles: immutable.Seq[RoleName] = roles): immutable.Seq[RoleName] = {
     roles.filterNot(_ == role)
   }
 
@@ -125,7 +126,7 @@ abstract class UnreachableNodeRejoinsClusterSpec(multiNodeConfig: UnreachableNod
       }
 
       runOn(allBut(victim): _*) {
-        awaitUpConvergence(roles.size - 1, Seq(victim))
+        awaitUpConvergence(roles.size - 1, List(victim))
       }
 
       endBarrier

akka-cluster/src/test/scala/akka/cluster/AccrualFailureDetectorSpec.scala

@@ -7,7 +7,7 @@ package akka.cluster
 import akka.actor.Address
 import akka.testkit._
 import akka.testkit.TestEvent._
-import scala.collection.immutable.TreeMap
+import scala.collection.immutable
 import scala.concurrent.duration._
 
 @org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
@@ -27,7 +27,7 @@ class AccrualFailureDetectorSpec extends AkkaSpec("""
     val conn = Address("akka", "", "localhost", 2552)
     val conn2 = Address("akka", "", "localhost", 2553)
 
-    def fakeTimeGenerator(timeIntervals: Seq[Long]): () ⇒ Long = {
+    def fakeTimeGenerator(timeIntervals: immutable.Seq[Long]): () ⇒ Long = {
       var times = timeIntervals.tail.foldLeft(List[Long](timeIntervals.head))((acc, c) ⇒ acc ::: List[Long](acc.last + c))
       def timeGenerator(): Long = {
         val currentTime = times.head
@@ -73,7 +73,7 @@ class AccrualFailureDetectorSpec extends AkkaSpec("""
 
     "return realistic phi values" in {
       val fd = createFailureDetector()
-      val test = TreeMap(0 -> 0.0, 500 -> 0.1, 1000 -> 0.3, 1200 -> 1.6, 1400 -> 4.7, 1600 -> 10.8, 1700 -> 15.3)
+      val test = immutable.TreeMap(0 -> 0.0, 500 -> 0.1, 1000 -> 0.3, 1200 -> 1.6, 1400 -> 4.7, 1600 -> 10.8, 1700 -> 15.3)
       for ((timeDiff, expectedPhi) ← test) {
         fd.phi(timeDiff = timeDiff, mean = 1000.0, stdDeviation = 100.0) must be(expectedPhi plusOrMinus (0.1))
       }

akka-cluster/src/test/scala/akka/cluster/MetricsCollectorSpec.scala

@@ -5,14 +5,16 @@
 package akka.cluster
 
 import scala.language.postfixOps
+
+import scala.collection.immutable
 import scala.concurrent.duration._
 import scala.concurrent.Await
+import scala.util.{ Success, Try, Failure }
 
 import akka.actor._
 import akka.testkit._
 import org.scalatest.WordSpec
 import org.scalatest.matchers.MustMatchers
-import util.{ Success, Try, Failure }
 
 object MetricsEnabledSpec {
   val config = """
@@ -109,8 +111,7 @@ class MetricsCollectorSpec extends AkkaSpec(MetricsEnabledSpec.config) with Impl
 
     "collect JMX metrics" in {
       // heap max may be undefined depending on the OS
-      // systemLoadAverage is JMX is SIGAR not present
+      // systemLoadAverage is JMX if SIGAR not present, but not available on all OS
-      collector.systemLoadAverage.isDefined must be(true)
       collector.used.isDefined must be(true)
       collector.committed.isDefined must be(true)
       collector.processors.isDefined must be(true)
@@ -208,11 +209,10 @@ trait MetricSpec extends WordSpec with MustMatchers {
     if (decay > 0) metrics.collect { case m if m.trendable && (!m.initializable) ⇒ m }.foreach(_.average.isDefined must be(true))
   }
 
-  def collectNodeMetrics(nodes: Set[NodeMetrics]): Seq[Metric] = {
+  def collectNodeMetrics(nodes: Set[NodeMetrics]): immutable.Seq[Metric] =
-    var r: Seq[Metric] = Seq.empty
+    nodes.foldLeft(Vector[Metric]()) {
-    nodes.foreach(n ⇒ r ++= n.metrics.filter(_.isDefined))
+      case (r, n) ⇒ r ++ n.metrics.filter(_.isDefined)
-    r
+    }
-  }
 }
 
 trait AbstractClusterMetricsSpec extends DefaultTimeout {

akka-contrib/docs/index.rst

@@ -29,6 +29,7 @@ The Current List of Modules
 .. toctree::
 
    reliable-proxy
+   throttle   
 
 Suggested Way of Using these Contributions
 ------------------------------------------

akka-contrib/docs/throttle.rst

@@ -0,0 +1,60 @@
+Throttling Actor Messages
+=========================
+
+Introduction
+------------
+
+Suppose you are writing an application that makes HTTP requests to an external
+web service and that this web service has a restriction in place: you may not
+make more than 10 requests in 1 minute. You will get blocked or need to pay if
+you don’t stay under this limit. In such a scenario you will want to employ
+a *message throttler*.
+
+This extension module provides a simple implementation of a throttling actor,
+the :class:`TimerBasedThrottler`.
+
+
+How to use it
+-------------
+
+You can use a :class:`TimerBasedThrottler` as follows:
+
+.. includecode:: @contribSrc@/src/test/scala/akka/contrib/throttle/TimerBasedThrottlerSpec.scala#demo-code
+
+Please refer to the ScalaDoc documentation for the details.
+
+
+The guarantees
+--------------
+
+:class:`TimerBasedThrottler` uses a timer internally. When the throttler’s rate is 3 msg/s,
+for example, the throttler will start a timer that triggers
+every second and each time will give the throttler exactly three "vouchers";
+each voucher gives the throttler a right to deliver a message. In this way,
+at most 3 messages will be sent out by the throttler in each interval.
+
+It should be noted that such timer-based throttlers provide relatively **weak guarantees**:
+
+* Only *start times* are taken into account. This may be a problem if, for example, the
+  throttler is used to throttle requests to an external web service. If a web request
+  takes very long on the server then the rate *observed on the server* may be higher.
+* A timer-based throttler only makes guarantees for the intervals of its own timer. In
+  our example, no more than 3 messages are delivered within such intervals. Other
+  intervals on the timeline, however, may contain more calls.
+
+The two cases are illustrated in the two figures below, each showing a timeline and three
+intervals of the timer. The message delivery times chosen by the throttler are indicated
+by dots, and as you can see, each interval contains at most 3 point, so the throttler
+works correctly. Still, there is in each example an interval (the red one) that is
+problematic. In the first scenario, this is because the delivery times are merely the
+start times of longer requests (indicated by the four bars above the timeline that start
+at the dots), so that the server observes four requests during the red interval. In the
+second scenario, the messages are centered around one of the points in time where the
+timer triggers, causing the red interval to contain too many messages.
+
+.. image:: throttler.png
+
+For some application scenarios, the guarantees provided by a timer-based throttler might
+be too weak. Charles Cordingley’s `blog post <http://www.cordinc.com/blog/2010/04/java-multichannel-asynchronous.html>`_
+discusses a throttler with stronger guarantees (it solves problem 2 from above).
+Future versions of this module may feature throttlers with better guarantees.

akka-contrib/src/main/scala/akka/contrib/throttle/TimerBasedThrottler.scala

@@ -0,0 +1,296 @@
+/**
+ *  Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.contrib.throttle
+
+import scala.concurrent.duration.{ Duration, FiniteDuration }
+import scala.util.control.NonFatal
+import scala.collection.immutable.{ Queue ⇒ Q }
+import akka.actor.{ ActorRef, Actor, FSM }
+import Throttler._
+import TimerBasedThrottler._
+import java.util.concurrent.TimeUnit
+import akka.AkkaException
+
+/**
+ * Marker trait for throttlers.
+ *
+ * == Throttling ==
+ * A <em>throttler</em> is an actor that is defined through a <em>target actor</em> and a <em>rate</em>
+ * (of type [[akka.contrib.throttle.Throttler.Rate]]). You set or change the target and rate at any time through the `SetTarget(target)`
+ * and `SetRate(rate)` messages, respectively. When you send the throttler any other message `msg`, it will
+ * put the message `msg` into an internal queue and eventually send all queued messages to the target, at
+ * a speed that respects the given rate. If no target is currently defined then the messages will be queued
+ * and will be delivered as soon as a target gets set.
+ *
+ * A [[akka.contrib.throttle.Throttler]] understands actor messages of type
+ * [[akka.contrib.throttle.Throttler.SetTarget]], [[akka.contrib.throttle.Throttler.SetRate]], in
+ * addition to any other messages, which the throttler will consider as messages to be sent to
+ * the target.
+ *
+ * == Transparency ==
+ * Notice that the throttler `forward`s messages, i.e., the target will see the original message sender (and not the throttler) as the sender of the message.
+ *
+ * == Persistence ==
+ * Throttlers usually use an internal queue to keep the messages that need to be sent to the target.
+ * You therefore cannot rely on the throttler's inbox size in order to learn how much messages are
+ * outstanding.
+ *
+ * It is left to the implementation whether the internal queue is persisted over application restarts or
+ * actor failure.
+ *
+ * == Processing messages ==
+ * The target should process messages as fast as possible. If the target requires substantial time to
+ * process messages, it should distribute its work to other actors (using for example something like
+ * a `BalancingDispatcher`), otherwise the resulting system will always work <em>below</em>
+ * the threshold rate.
+ *
+ * <em>Example:</em> Suppose the throttler has a rate of 3msg/s and the target requires 1s to process a message.
+ * This system will only process messages at a rate of 1msg/s: the target will receive messages at at most 3msg/s
+ * but as it handles them synchronously and each of them takes 1s, its inbox will grow and grow. In such
+ * a situation, the target should <em>distribute</em> its messages to a set of worker actors so that individual messages
+ * can be handled in parallel.
+ *
+ * @see [[akka.contrib.throttle.TimerBasedThrottler]]
+ */
+trait Throttler { this: Actor ⇒ }
+
+/**
+ * Message types understood by [[akka.contrib.throttle.Throttler]]'s.
+ *
+ * @see [[akka.contrib.throttle.Throttler]]
+ * @see [[akka.contrib.throttle.Throttler.Rate]]
+ */
+object Throttler {
+  /**
+   * A rate used for throttling.
+   *
+   * There are some shorthands available to construct rates:
+   * {{{
+   *  import java.util.concurrent.TimeUnit._
+   *  import scala.concurrent.duration.{ Duration, FiniteDuration }
+   *
+   *  val rate1 = 1 msgsPer (1, SECONDS)
+   *  val rate2 = 1 msgsPer Duration(1, SECONDS)
+   *  val rate3 = 1 msgsPer (1 seconds)
+   *  val rate4 = 1 msgsPerSecond
+   *  val rate5 = 1 msgsPerMinute
+   *  val rate6 = 1 msgsPerHour
+   * }}}
+   *
+   * @param numberOfCalls the number of calls that may take place in a period
+   * @param duration the length of the period
+   * @see [[akka.contrib.throttle.Throttler]]
+   */
+  case class Rate(val numberOfCalls: Int, val duration: FiniteDuration) {
+    /**
+     * The duration in milliseconds.
+     */
+    def durationInMillis(): Long = duration.toMillis
+  }
+
+  /**
+   * Set the target of a [[akka.contrib.throttle.Throttler]].
+   *
+   * You may change a throttler's target at any time.
+   *
+   * Notice that the messages sent by the throttler to the target will have the original sender (and
+   * not the throttler) as the sender. (In Akka terms, the throttler `forward`s the message.)
+   *
+   * @param target if `target` is `None`, the throttler will stop delivering messages and the messages already received
+   *  but not yet delivered, as well as any messages received in the future will be queued
+   *  and eventually be delivered when a new target is set. If `target` is not `None`, the currently queued messages
+   *  as well as any messages received in the the future will be delivered to the new target at a rate not exceeding the current throttler's rate.
+   */
+  case class SetTarget(target: Option[ActorRef])
+
+  /**
+   * Set the rate of a [[akka.contrib.throttle.Throttler]].
+   *
+   * You may change a throttler's rate at any time.
+   *
+   * @param rate the rate at which messages will be delivered to the target of the throttler
+   */
+  case class SetRate(rate: Rate)
+
+  import language.implicitConversions
+
+  /**
+   * Helper for some syntactic sugar.
+   *
+   * @see [[akka.contrib.throttle.Throttler.Rate]]
+   */
+  implicit class RateInt(val numberOfCalls: Int) extends AnyVal {
+    def msgsPer(duration: Int, timeUnit: TimeUnit) = Rate(numberOfCalls, Duration(duration, timeUnit))
+    def msgsPer(duration: FiniteDuration) = Rate(numberOfCalls, duration)
+    def msgsPerSecond = Rate(numberOfCalls, Duration(1, TimeUnit.SECONDS))
+    def msgsPerMinute = Rate(numberOfCalls, Duration(1, TimeUnit.MINUTES))
+    def msgsPerHour = Rate(numberOfCalls, Duration(1, TimeUnit.HOURS))
+  }
+
+}
+
+/**
+ * Implementation-specific internals.
+ */
+object TimerBasedThrottler {
+  private[throttle] case object Tick
+
+  // States of the FSM: A `TimerBasedThrottler` is in state `Active` iff the timer is running.
+  private[throttle] sealed trait State
+  private[throttle] case object Idle extends State
+  private[throttle] case object Active extends State
+
+  // Messages, as we queue them to be sent later
+  private[throttle] case class Message(message: Any, sender: ActorRef)
+
+  // The data of the FSM
+  private[throttle] sealed case class Data(target: Option[ActorRef],
+                                           callsLeftInThisPeriod: Int,
+                                           queue: Q[Message])
+}
+
+/**
+ * A [[akka.contrib.throttle.Throttler]] that uses a timer to control the message delivery rate.
+ *
+ * ==Example==
+ * For example, if you set a rate like "3 messages in 1 second", the throttler
+ * will send the first three messages immediately to the target actor but will need to impose a delay before
+ * sending out further messages:
+ * {{{
+ *   // A simple actor that prints whatever it receives
+ *   val printer = system.actorOf(Props(new Actor {
+ *     def receive = {
+ *       case x => println(x)
+ *     }
+ *   }))
+ *   // The throttler for this example, setting the rate
+ *   val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second))))
+ *   // Set the target
+ *   throttler ! SetTarget(Some(printer))
+ *   // These three messages will be sent to the printer immediately
+ *   throttler ! "1"
+ *   throttler ! "2"
+ *   throttler ! "3"
+ *   // These two will wait at least until 1 second has passed
+ *   throttler ! "4"
+ *   throttler ! "5"
+ * }}}
+ *
+ * ==Implementation notes==
+ * This throttler implementation internally installs a timer that repeats every `rate.durationInMillis` and enables `rate.numberOfCalls`
+ * additional calls to take place. A `TimerBasedThrottler` uses very few system resources, provided the rate's duration is not too
+ * fine-grained (which would cause a lot of timer invocations); for example, it does not store the calling history
+ * as other throttlers may need to do.
+ *
+ * However, a `TimerBasedThrottler` only provides ''weak guarantees'' on the rate (see also
+ * <a href='http://letitcrash.com/post/28901663062/throttling-messages-in-akka-2'>this blog post</a>):
+ *
+ *  - Only ''delivery'' times are taken into account: if, for example, the throttler is used to throttle
+ *    requests to an external web service then only the start times of the web requests are considered.
+ *    If a web request takes very long on the server then more than `rate.numberOfCalls`-many requests
+ *    may be observed on the server in an interval of duration `rate.durationInMillis()`.
+ *  - There may be intervals of duration `rate.durationInMillis()` that contain more than `rate.numberOfCalls`
+ *    message deliveries: a `TimerBasedThrottler` only makes guarantees for the intervals
+ *    of its ''own'' timer, namely that no more than `rate.numberOfCalls`-many messages are delivered within such intervals. Other intervals on the
+ *    timeline may contain more calls.
+ *
+ * For some applications, these guarantees may not be sufficient.
+ *
+ * ==Known issues==
+ *
+ *  - If you change the rate using `SetRate(rate)`, the actual rate may in fact be higher for the
+ *    overlapping period (i.e., `durationInMillis()`) of the new and old rate. Therefore,
+ *    changing the rate frequently is not recommended with the current implementation.
+ *  - The queue of messages to be delivered is not persisted in any way; actor or system failure will
+ *    cause the queued messages to be lost.
+ *
+ * @see [[akka.contrib.throttle.Throttler]]
+ */
+class TimerBasedThrottler(var rate: Rate) extends Actor with Throttler with FSM[State, Data] {
+  startWith(Idle, Data(None, rate.numberOfCalls, Q()))
+
+  // Idle: no messages, or target not set
+  when(Idle) {
+    // Set the rate
+    case Event(SetRate(rate), d) ⇒
+      this.rate = rate
+      stay using d.copy(callsLeftInThisPeriod = rate.numberOfCalls)
+
+    // Set the target
+    case Event(SetTarget(t @ Some(_)), d) if !d.queue.isEmpty ⇒
+      goto(Active) using deliverMessages(d.copy(target = t))
+    case Event(SetTarget(t), d) ⇒
+      stay using d.copy(target = t)
+
+    // Queuing
+    case Event(msg, d @ Data(None, _, queue)) ⇒
+      stay using d.copy(queue = queue.enqueue(Message(msg, context.sender)))
+    case Event(msg, d @ Data(Some(_), _, Seq())) ⇒
+      goto(Active) using deliverMessages(d.copy(queue = Q(Message(msg, context.sender))))
+    // Note: The case Event(msg, t @ Data(Some(_), _, _, Seq(_*))) should never happen here.
+  }
+
+  when(Active) {
+    // Set the rate
+    case Event(SetRate(rate), d) ⇒
+      this.rate = rate
+      // Note: this should be improved (see "Known issues" in class comments)
+      stopTimer()
+      startTimer(rate)
+      stay using d.copy(callsLeftInThisPeriod = rate.numberOfCalls)
+
+    // Set the target (when the new target is None)
+    case Event(SetTarget(None), d) ⇒
+      // Note: We do not yet switch to state `Inactive` because we need the timer to tick once more before
+      stay using d.copy(target = None)
+
+    // Set the target (when the new target is not None)
+    case Event(SetTarget(t @ Some(_)), d) ⇒
+      stay using d.copy(target = t)
+
+    // Tick after a `SetTarget(None)`: take the additional permits and go to `Idle`
+    case Event(Tick, d @ Data(None, _, _)) ⇒
+      goto(Idle) using d.copy(callsLeftInThisPeriod = rate.numberOfCalls)
+
+    // Period ends and we have no more messages: take the additional permits and go to `Idle`
+    case Event(Tick, d @ Data(_, _, Seq())) ⇒
+      goto(Idle) using d.copy(callsLeftInThisPeriod = rate.numberOfCalls)
+
+    // Period ends and we get more occasions to send messages
+    case Event(Tick, d @ Data(_, _, _)) ⇒
+      stay using deliverMessages(d.copy(callsLeftInThisPeriod = rate.numberOfCalls))
+
+    // Queue a message (when we cannot send messages in the current period anymore)
+    case Event(msg, d @ Data(_, 0, queue)) ⇒
+      stay using d.copy(queue = queue.enqueue(Message(msg, context.sender)))
+
+    // Queue a message (when we can send some more messages in the current period)
+    case Event(msg, d @ Data(_, _, queue)) ⇒
+      stay using deliverMessages(d.copy(queue = queue.enqueue(Message(msg, context.sender))))
+  }
+
+  onTransition {
+    case Idle -> Active ⇒ startTimer(rate)
+    case Active -> Idle ⇒ stopTimer()
+  }
+
+  initialize
+
+  private def startTimer(rate: Rate) = setTimer("morePermits", Tick, rate.duration, true)
+  private def stopTimer() = cancelTimer("morePermits")
+
+  /**
+   * Send as many messages as we can (while respecting the rate) to the target and
+   * return the state data (with the queue containing the remaining ones).
+   */
+  private def deliverMessages(data: Data): Data = {
+    val queue = data.queue
+    val nrOfMsgToSend = scala.math.min(queue.length, data.callsLeftInThisPeriod)
+
+    queue.take(nrOfMsgToSend).foreach(x ⇒ data.target.get.tell(x.message, x.sender))
+
+    data.copy(queue = queue.drop(nrOfMsgToSend), callsLeftInThisPeriod = data.callsLeftInThisPeriod - nrOfMsgToSend)
+  }
+}

akka-contrib/src/multi-jvm/scala/akka/contrib/pattern/ReliableProxySpec.scala

@@ -122,8 +122,8 @@ class ReliableProxySpec extends MultiNodeSpec(ReliableProxySpec) with STMultiNod
       enterBarrier("test2b")
       
       runOn(local) {
-        testConductor.throttle(local, remote, Direction.Send, -1)
+        testConductor.throttle(local, remote, Direction.Send, -1).await
-        expectTransition(Active, Idle)
+        within(5 seconds) { expectTransition(Active, Idle) }
       }
       runOn(remote) {
         within(1 second) {
@@ -152,8 +152,8 @@ class ReliableProxySpec extends MultiNodeSpec(ReliableProxySpec) with STMultiNod
       enterBarrier("test3a")
       
       runOn(local) {
-        testConductor.throttle(local, remote, Direction.Receive, -1)
+        testConductor.throttle(local, remote, Direction.Receive, -1).await
-        expectTransition(Active, Idle)
+        within(5 seconds) { expectTransition(Active, Idle) }
       }
       
       enterBarrier("test3b")

akka-contrib/src/test/scala/akka/contrib/throttle/TimerBasedThrottlerSpec.scala

@@ -0,0 +1,205 @@
+/**
+ *  Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.contrib.throttle
+
+import language.postfixOps
+import scala.concurrent.duration._
+import akka.actor.ActorSystem
+import akka.actor.Actor
+import akka.actor.Props
+import akka.testkit.TestKit
+import akka.testkit.ImplicitSender
+import akka.contrib.throttle.Throttler._
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+import org.scalatest.WordSpec
+import org.scalatest.matchers.MustMatchers
+import org.scalatest.BeforeAndAfterAll
+import akka.testkit._
+
+object TimerBasedThrottlerSpec {
+  class EchoActor extends Actor {
+    def receive = {
+      case x ⇒ sender ! x
+    }
+  }
+}
+
+@RunWith(classOf[JUnitRunner])
+class TimerBasedThrottlerSpec extends TestKit(ActorSystem("TimerBasedThrottlerSpec")) with ImplicitSender
+  with WordSpec with MustMatchers with BeforeAndAfterAll {
+
+  override def afterAll {
+    system.shutdown()
+  }
+
+  "A throttler" must {
+    def println(a: Any) = ()
+    "must pass the ScalaDoc class documentation example program" in {
+      //#demo-code
+      // A simple actor that prints whatever it receives
+      val printer = system.actorOf(Props(new Actor {
+        def receive = {
+          case x ⇒ println(x)
+        }
+      }))
+      // The throttler for this example, setting the rate
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second.dilated))))
+      // Set the target 
+      throttler ! SetTarget(Some(printer))
+      // These three messages will be sent to the echoer immediately
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      // These two will wait until a second has passed
+      throttler ! "4"
+      throttler ! "5"
+      //#demo-code
+    }
+
+    "keep messages until a target is set" in {
+      val echo = system.actorOf(Props[TimerBasedThrottlerSpec.EchoActor])
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second.dilated))))
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      throttler ! "4"
+      throttler ! "5"
+      throttler ! "6"
+      expectNoMsg(1 second)
+      throttler ! SetTarget(Some(echo))
+      within(2 seconds) {
+        expectMsg("1")
+        expectMsg("2")
+        expectMsg("3")
+        expectMsg("4")
+        expectMsg("5")
+        expectMsg("6")
+      }
+    }
+
+    "send messages after a `SetTarget(None)` pause" in {
+      val echo = system.actorOf(Props[TimerBasedThrottlerSpec.EchoActor])
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second.dilated))))
+      throttler ! SetTarget(Some(echo))
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      throttler ! SetTarget(None)
+      within(1 second) {
+        expectMsg("1")
+        expectMsg("2")
+        expectMsg("3")
+        expectNoMsg()
+      }
+      expectNoMsg(1 second)
+      throttler ! SetTarget(Some(echo))
+      throttler ! "4"
+      throttler ! "5"
+      throttler ! "6"
+      throttler ! "7"
+      within(1 seconds) {
+        expectMsg("4")
+        expectMsg("5")
+        expectMsg("6")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("7")
+      }
+    }
+
+    "keep messages when the target is set to None" in {
+      val echo = system.actorOf(Props[TimerBasedThrottlerSpec.EchoActor])
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second.dilated))))
+      throttler ! SetTarget(Some(echo))
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      throttler ! "4"
+      throttler ! "5"
+      throttler ! "6"
+      throttler ! "7"
+      throttler ! SetTarget(None)
+      within(1 second) {
+        expectMsg("1")
+        expectMsg("2")
+        expectMsg("3")
+        expectNoMsg()
+      }
+      expectNoMsg(1 second)
+      throttler ! SetTarget(Some(echo))
+      within(1 seconds) {
+        expectMsg("4")
+        expectMsg("5")
+        expectMsg("6")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("7")
+      }
+    }
+
+    "respect the rate (3 msg/s)" in {
+      val echo = system.actorOf(Props[TimerBasedThrottlerSpec.EchoActor])
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(3 msgsPer (1.second.dilated))))
+      throttler ! SetTarget(Some(echo))
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      throttler ! "4"
+      throttler ! "5"
+      throttler ! "6"
+      throttler ! "7"
+      within(1 second) {
+        expectMsg("1")
+        expectMsg("2")
+        expectMsg("3")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("4")
+        expectMsg("5")
+        expectMsg("6")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("7")
+      }
+    }
+
+    "respect the rate (4 msg/s)" in {
+      val echo = system.actorOf(Props[TimerBasedThrottlerSpec.EchoActor])
+      val throttler = system.actorOf(Props(new TimerBasedThrottler(4 msgsPer (1.second.dilated))))
+      throttler ! SetTarget(Some(echo))
+      throttler ! "1"
+      throttler ! "2"
+      throttler ! "3"
+      throttler ! "4"
+      throttler ! "5"
+      throttler ! "6"
+      throttler ! "7"
+      throttler ! "8"
+      throttler ! "9"
+      within(1 second) {
+        expectMsg("1")
+        expectMsg("2")
+        expectMsg("3")
+        expectMsg("4")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("5")
+        expectMsg("6")
+        expectMsg("7")
+        expectMsg("8")
+        expectNoMsg()
+      }
+      within(1 second) {
+        expectMsg("9")
+      }
+    }
+  }
+}

akka-dataflow/src/main/scala/akka/dataflow/package.scala

@@ -46,7 +46,7 @@ package object dataflow {
   implicit class DataflowPromise[T](val promise: Promise[T]) extends AnyVal {
 
     /**
-     * Completes the Promise with the speicifed value or throws an exception if already
+     * Completes the Promise with the specified value or throws an exception if already
      * completed. See Promise.success(value) for semantics.
      *
      * @param value The value which denotes the successful value of the Promise
@@ -59,7 +59,7 @@ package object dataflow {
     /**
      * Completes this Promise with the value of the specified Future when/if it completes.
      *
-     * @param other The Future whose value will be transfered to this Promise upon completion
+     * @param other The Future whose value will be transferred to this Promise upon completion
      * @param ec An ExecutionContext which will be used to execute callbacks registered in this method
      * @return A Future representing the result of this operation
      */
@@ -75,7 +75,7 @@ package object dataflow {
     /**
      * Completes this Promise with the value of the specified Promise when/if it completes.
      *
-     * @param other The Promise whose value will be transfered to this Promise upon completion
+     * @param other The Promise whose value will be transferred to this Promise upon completion
      * @param ec An ExecutionContext which will be used to execute callbacks registered in this method
      * @return A Future representing the result of this operation
      */

akka-docs/rst/common/duration.rst

@@ -5,7 +5,7 @@ Duration
 ########
 
 Durations are used throughout the Akka library, wherefore this concept is
-represented by a special data type, :class:`scala.concurrent.util.Duration`.
+represented by a special data type, :class:`scala.concurrent.duration.Duration`.
 Values of this type may represent infinite (:obj:`Duration.Inf`,
 :obj:`Duration.MinusInf`) or finite durations, or be :obj:`Duration.Undefined`.
 

akka-docs/rst/dev/documentation.rst

@@ -17,13 +17,12 @@ built using `Sphinx`_.
 Sphinx
 ======
 
-More to come...
+For more details see `The Sphinx Documentation <http://sphinx.pocoo.org/contents.html>`_
-
 
 reStructuredText
 ================
 
-More to come...
+For more details see `The reST Quickref <http://docutils.sourceforge.net/docs/user/rst/quickref.html>`_
 
 Sections
 --------
@@ -75,16 +74,17 @@ First install `Sphinx`_. See below.
 Building
 --------
 
-::
+For the html version of the docs::
 
-  cd akka-docs
+    sbt sphinx:generate-html
 
-  make html
+    open <project-dir>/akka-docs/target/sphinx/html/index.html
-  open _build/html/index.html
 
-  make pdf
+For the pdf version of the docs::
-  open _build/latex/Akka.pdf
 
+    sbt sphinx:generate-pdf
+
+    open <project-dir>/akka-docs/target/sphinx/latex/Akka.pdf
 
 Installing Sphinx on OS X
 -------------------------

akka-docs/rst/dev/multi-jvm-testing.rst

@@ -18,52 +18,65 @@ You can add it as a plugin by adding the following to your project/plugins.sbt:
 .. includecode:: ../../../project/plugins.sbt#sbt-multi-jvm
 
 You can then add multi-JVM testing to ``project/Build.scala`` by including the ``MultiJvm``
-settings and config. For example, here is an example of how the akka-remote-tests project adds
+settings and config. Please note that MultiJvm test sources are located in ``src/multi-jvm/...``,
-multi-JVM testing (Simplified for clarity):
+and not in ``src/test/...``.
+
+Here is an example Build.scala file that uses the MultiJvm plugin:
 
 .. parsed-literal::
 
    import sbt._
    import Keys._
    import com.typesafe.sbt.SbtMultiJvm
-   import com.typesafe.sbt.SbtMultiJvm.MultiJvmKeys.{ MultiJvm, extraOptions }
+   import com.typesafe.sbt.SbtMultiJvm.MultiJvmKeys.{ MultiJvm }
 
-   object AkkaBuild extends Build {
+   object ExampleBuild extends Build {
 
-    lazy val remoteTests = Project(
+     lazy val buildSettings = Defaults.defaultSettings ++ multiJvmSettings ++ Seq(
-      id = "akka-remote-tests",
+       organization := "example",
-      base = file("akka-remote-tests"),
+       version      := "1.0",
-      dependencies = Seq(remote, actorTests % "test->test",
+       scalaVersion := "@scalaVersion@",
-        testkit % "test->test"),
+       // make sure that the artifacts don't have the scala version in the name
-      settings = defaultSettings ++ Seq(
+       crossPaths   := false
-        // disable parallel tests
+     )
-        parallelExecution in Test := false,
-        extraOptions in MultiJvm <<= (sourceDirectory in MultiJvm) { src =>
-          (name: String) => (src ** (name + ".conf")).get.
-            headOption.map("-Dakka.config=" + _.absolutePath).toSeq
-        },
-        executeTests in Test <<= ((executeTests in Test),
-                                  (executeTests in MultiJvm)) map {
-          case ((_, testResults), (_, multiJvmResults)) =>
-            val results = testResults ++ multiJvmResults
-            (Tests.overall(results.values), results)
-        }
-      )
-    ) configs (MultiJvm)
 
-    lazy val buildSettings = Defaults.defaultSettings ++
+     lazy val example = Project(
-      SbtMultiJvm.multiJvmSettings ++ Seq(
+       id = "example",
-      organization := "com.typesafe.akka",
+       base = file("."),
-      version      := "@version@",
+       settings = buildSettings ++
-      scalaVersion := "@scalaVersion@",
+         Seq(libraryDependencies ++= Dependencies.example)
-      crossPaths   := false
+     ) configs(MultiJvm)
-    )
 
-    lazy val defaultSettings = buildSettings ++ Seq(
+     lazy val multiJvmSettings = SbtMultiJvm.multiJvmSettings ++ Seq(
-      resolvers += "Typesafe Repo" at "http://repo.typesafe.com/typesafe/releases/"
+       // make sure that MultiJvm test are compiled by the default test compilation
-    )
+       compile in MultiJvm <<= (compile in MultiJvm) triggeredBy (compile in Test),
+       // disable parallel tests
+       parallelExecution in Test := false,
+       // make sure that MultiJvm tests are executed by the default test target
+       executeTests in Test <<=
+         ((executeTests in Test), (executeTests in MultiJvm)) map {
+           case ((_, testResults), (_, multiJvmResults))  =>
+             val results = testResults ++ multiJvmResults
+             (Tests.overall(results.values), results)
+       }
+     )
 
-  }
+     object Dependencies {
+       val example = Seq(
+         // ---- application dependencies ----
+         "com.typesafe.akka"  %% "akka-actor" % "@version@" @crossString@,
+         "com.typesafe.akka"  %% "akka-remote" % "@version@" @crossString@,
+
+         // ---- test dependencies ----
+         "com.typesafe.akka" %% "akka-testkit" % "@version@" %
+           "test" cross CrossVersion.full,
+         "com.typesafe.akka" %% "akka-remote-tests-experimental" % "@version@" %
+           "test" cross CrossVersion.full,
+         "org.scalatest"     %% "scalatest" % "1.8-B2" % "test" cross CrossVersion.full,
+         "junit"              % "junit" % "4.5" % "test"
+       )
+     }
+   }
 
 You can specify JVM options for the forked JVMs::
 
@@ -73,7 +86,7 @@ You can specify JVM options for the forked JVMs::
 Running tests
 =============
 
-The multi-jvm tasks are similar to the normal tasks: ``test``, ``test-only``,
+The multi-JVM tasks are similar to the normal tasks: ``test``, ``test-only``,
 and ``run``, but are under the ``multi-jvm`` configuration.
 
 So in Akka, to run all the multi-JVM tests in the akka-remote project use (at
@@ -111,8 +124,8 @@ options after the test names and ``--``. For example:
 Creating application tests
 ==========================
 
-The tests are discovered, and combined, through a naming convention. MultiJvm tests are
+The tests are discovered, and combined, through a naming convention. MultiJvm test sources
-located in ``src/multi-jvm/scala`` directory. A test is named with the following pattern:
+are located in ``src/multi-jvm/...``. A test is named with the following pattern:
 
 .. code-block:: none
 
@@ -162,14 +175,26 @@ spawned, one for each node. It will look like this:
     [success] Total time: ...
 
 
-Naming
+Changing Defaults
-======
+=================
+
+You can chenge the name of the multi-JVM test source directory by adding the following
+configuration to your project:
+
+.. code-block:: none
+
+   unmanagedSourceDirectories in MultiJvm <<=
+      Seq(baseDirectory(_ / "src/some_directory_here")).join
+
 
 You can change what the ``MultiJvm`` identifier is. For example, to change it to
-``ClusterTest`` use the ``multiJvmMarker`` setting::
+``ClusterTest`` use the ``multiJvmMarker`` setting:
+
+.. code-block:: none
 
    multiJvmMarker in MultiJvm := "ClusterTest"
 
+
 Your tests should now be named ``{TestName}ClusterTest{NodeName}``.
 
 

akka-docs/rst/general/actor-systems.rst

@@ -108,8 +108,8 @@ Actor Best Practices
 #. Top-level actors are the innermost part of your Error Kernel, so create them
    sparingly and prefer truly hierarchical systems. This has benefits wrt.
    fault-handling (both considering the granularity of configuration and the
-   performance) and it also reduces the number of blocking calls made, since
+   performance) and it also reduces the strain on the guardian actor, which is
-   the creation of top-level actors involves synchronous messaging.
+   a single point of contention if over-used.
 
 Blocking Needs Careful Management
 ---------------------------------

akka-docs/rst/java/code/docs/actor/FaultHandlingTestBase.java

@@ -27,10 +27,11 @@ import akka.testkit.ErrorFilter;
 import akka.testkit.EventFilter;
 import akka.testkit.TestEvent;
 import static java.util.concurrent.TimeUnit.SECONDS;
+import static akka.japi.Util.immutableSeq;
 import akka.japi.Function;
 import scala.Option;
 import scala.collection.JavaConverters;
-import scala.collection.Seq;
+import scala.collection.immutable.Seq;
 
 import org.junit.Test;
 import org.junit.BeforeClass;
@@ -219,8 +220,7 @@ public class FaultHandlingTestBase {
 
   //#testkit
   public <A> Seq<A> seq(A... args) {
-    return JavaConverters.collectionAsScalaIterableConverter(
+    return immutableSeq(args);
-      java.util.Arrays.asList(args)).asScala().toSeq();
   }
   //#testkit
 }

akka-docs/rst/java/code/docs/actor/UntypedActorDocTestBase.java

@@ -351,24 +351,23 @@ public class UntypedActorDocTestBase {
   static
   //#stash
   public class ActorWithProtocol extends UntypedActorWithStash {
-    private Boolean isOpen = false;
     public void onReceive(Object msg) {
-      if (isOpen) {
+      if (msg.equals("open")) {
-        if (msg.equals("write")) {
+        unstashAll();
-          // do writing...
+        getContext().become(new Procedure<Object>() {
-        } else if (msg.equals("close")) {
+          public void apply(Object msg) throws Exception {
-          unstashAll();
+            if (msg.equals("write")) {
-          isOpen = false;
+              // do writing...
-        } else {
+            } else if (msg.equals("close")) {
-          stash();
+              unstashAll();
-        }
+              getContext().unbecome();
+            } else {
+              stash();
+            }
+          }
+        }, false); // add behavior on top instead of replacing
       } else {
-        if (msg.equals("open")) {
+        stash();
-          unstashAll();
-          isOpen = true;
-        } else {
-          stash();
-        }
       }
     }
   }

akka-docs/rst/java/code/docs/actor/UntypedActorSwapper.java

@@ -32,9 +32,9 @@ public class UntypedActorSwapper {
           @Override
           public void apply(Object message) {
             log.info("Ho");
-            getContext().unbecome(); // resets the latest 'become' (just for fun)
+            getContext().unbecome(); // resets the latest 'become'
           }
-        });
+        }, false); // this signals stacking of the new behavior
       } else {
         unhandled(message);
       }

akka-docs/rst/java/code/docs/event/LoggingDocTestBase.java

@@ -119,5 +119,4 @@ public class LoggingDocTestBase {
     }
   }
   //#deadletter-actor
-
 }

akka-docs/rst/java/code/docs/jrouting/CustomRouterDocTestBase.java

@@ -11,6 +11,7 @@ import static docs.jrouting.CustomRouterDocTestBase.Message.RepublicanVote;
 import static org.junit.Assert.assertEquals;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import org.junit.After;
@@ -69,7 +70,7 @@ public class CustomRouterDocTestBase {
     //#supervision
     final SupervisorStrategy strategy =
       new OneForOneStrategy(5, Duration.create("1 minute"),
-        new Class<?>[] { Exception.class });
+         Collections.<Class<? extends Throwable>>singletonList(Exception.class));
     final ActorRef router = system.actorOf(new Props(MyActor.class)
         .withRouter(new RoundRobinRouter(5).withSupervisorStrategy(strategy)));
     //#supervision
@@ -179,16 +180,14 @@ public class CustomRouterDocTestBase {
       //#crRoutingLogic
       return new CustomRoute() {
         @Override
-        public Iterable<Destination> destinationsFor(ActorRef sender, Object msg) {
+        public scala.collection.immutable.Seq<Destination> destinationsFor(ActorRef sender, Object msg) {
           switch ((Message) msg) {
           case DemocratVote:
           case DemocratCountResult:
-            return Arrays.asList(
+            return akka.japi.Util.immutableSingletonSeq(new Destination(sender, democratActor));
-              new Destination[] { new Destination(sender, democratActor) });
           case RepublicanVote:
           case RepublicanCountResult:
-            return Arrays.asList(
+            return akka.japi.Util.immutableSingletonSeq(new Destination(sender, republicanActor));
-              new Destination[] { new Destination(sender, republicanActor) });
           default:
             throw new IllegalArgumentException("Unknown message: " + msg);
           }

akka-docs/rst/java/untyped-actors.rst

@@ -549,7 +549,8 @@ Upgrade
 
 Akka supports hotswapping the Actor’s message loop (e.g. its implementation) at
 runtime. Use the ``getContext().become`` method from within the Actor.
-The hotswapped code is kept in a Stack which can be pushed and popped.
+The hotswapped code is kept in a Stack which can be pushed (replacing or adding
+at the top) and popped.
 
 .. warning::
 
@@ -563,26 +564,19 @@ To hotswap the Actor using ``getContext().become``:
 .. includecode:: code/docs/actor/UntypedActorDocTestBase.java
    :include: hot-swap-actor
 
-The ``become`` method is useful for many different things, such as to implement
+This variant of the :meth:`become` method is useful for many different things,
-a Finite State Machine (FSM).
+such as to implement a Finite State Machine (FSM). It will replace the current
+behavior (i.e. the top of the behavior stack), which means that you do not use
+:meth:`unbecome`, instead always the next behavior is explicitly installed.
 
-Here is another little cute example of ``become`` and ``unbecome`` in action:
+The other way of using :meth:`become` does not replace but add to the top of
+the behavior stack. In this case care must be taken to ensure that the number
+of “pop” operations (i.e. :meth:`unbecome`) matches the number of “push” ones
+in the long run, otherwise this amounts to a memory leak (which is why this
+behavior is not the default). 
 
 .. includecode:: code/docs/actor/UntypedActorSwapper.java#swapper
 
-Downgrade
----------
-
-Since the hotswapped code is pushed to a Stack you can downgrade the code as
-well. Use the ``getContext().unbecome`` method from within the Actor.
-
-.. code-block:: java
-
-  public void onReceive(Object message) {
-    if (message.equals("revert")) getContext().unbecome();
-  }
-
-
 Stash
 =====
 
@@ -627,9 +621,11 @@ The stash is backed by a ``scala.collection.immutable.Vector``. As a
 result, even a very large number of messages may be stashed without a
 major impact on performance.
 
-Note that the stash is not persisted across restarts of an actor,
+Note that the stash is part of the ephemeral actor state, unlike the
-unlike the actor's mailbox. Therefore, it should be managed like other
+mailbox. Therefore, it should be managed like other parts of the
-parts of the actor's state which have the same property.
+actor's state which have the same property. The :class:`Stash` trait’s
+implementation of :meth:`preRestart` will call ``unstashAll()``, which is
+usually the desired behavior.
 
 
 Killing an Actor

akka-docs/rst/project/migration-guide-2.1.x-2.2.x.rst

@@ -0,0 +1,26 @@
+.. _migration-2.2:
+
+################################
+ Migration Guide 2.1.x to 2.2.x
+################################
+
+The 2.2 release contains several structural changes that require some
+simple, mechanical source-level changes in client code.
+
+When migrating from 1.3.x to 2.1.x you should first follow the instructions for
+migrating `1.3.x to 2.0.x <http://doc.akka.io/docs/akka/2.0.3/project/migration-guide-1.3.x-2.0.x.html>`_ and then :ref:`2.0.x to 2.1.x <migration-2.1>`.
+
+Immutable everywhere
+====================
+
+Akka has in 2.2 been refactored to require ``scala.collection.immutable`` data structures as much as possible,
+this leads to fewer bugs and more opportunity for sharing data safely.
+
+==================================== ====================================
+Search                               Replace with
+==================================== ====================================
+``akka.japi.Util.arrayToSeq``          ``akka.japi.Util.immutableSeq``
+==================================== ====================================
+
+If you need to convert from Java to ``scala.collection.immutable.Seq`` or ``scala.collection.immutable.Iterable`` you should use ``akka.japi.Util.immutableSeq(…)``,
+and if you need to convert from Scala you can simply switch to using immutable collections yourself or use the ``to[immutable.<collection-type>]`` method.

akka-docs/rst/project/migration-guides.rst

@@ -8,3 +8,4 @@ Migration Guides
 
    migration-guide-1.3.x-2.0.x
    migration-guide-2.0.x-2.1.x
+   migration-guide-2.1.x-2.2.x

akka-docs/rst/scala/actors.rst

@@ -174,6 +174,17 @@ form of the ``implicit val context: ActorContext``. Outside of an actor, you
 have to either declare an implicit :class:`ActorSystem`, or you can give the
 factory explicitly (see further below).
 
+The two possible ways of issuing a ``context.become`` (replacing or adding the
+new behavior) are offered separately to enable a clutter-free notation of
+nested receives:
+
+.. includecode:: ../../../akka-actor-tests/src/test/scala/akka/actor/ActorDSLSpec.scala#becomeStacked
+
+Please note that calling ``unbecome`` more often than ``becomeStacked`` results
+in the original behavior being installed, which in case of the :class:`Act`
+trait is the empty behavior (the outer ``become`` just replaces it during
+construction).
+
 Life-cycle hooks are also exposed as DSL elements (see `Start Hook`_ and `Stop
 Hook`_ below), where later invocations of the methods shown below will replace
 the contents of the respective hooks:
@@ -653,11 +664,10 @@ Upgrade
 -------
 
 Akka supports hotswapping the Actor’s message loop (e.g. its implementation) at
-runtime: Invoke the ``context.become`` method from within the Actor.
+runtime: invoke the ``context.become`` method from within the Actor.
-
+:meth:`become` takes a ``PartialFunction[Any, Unit]`` that implements the new
-Become takes a ``PartialFunction[Any, Unit]`` that implements
+message handler. The hotswapped code is kept in a Stack which can be pushed and
-the new message handler. The hotswapped code is kept in a Stack which can be
+popped.
-pushed and popped.
 
 .. warning::
 
@@ -667,38 +677,26 @@ To hotswap the Actor behavior using ``become``:
 
 .. includecode:: code/docs/actor/ActorDocSpec.scala#hot-swap-actor
 
-The ``become`` method is useful for many different things, but a particular nice
+This variant of the :meth:`become` method is useful for many different things,
-example of it is in example where it is used to implement a Finite State Machine
+such as to implement a Finite State Machine (FSM, for an example see `Dining
-(FSM): `Dining Hakkers`_.
+Hakkers`_). It will replace the current behavior (i.e. the top of the behavior
+stack), which means that you do not use :meth:`unbecome`, instead always the
+next behavior is explicitly installed.
 
 .. _Dining Hakkers: @github@/akka-samples/akka-sample-fsm/src/main/scala/DiningHakkersOnBecome.scala
 
-Here is another little cute example of ``become`` and ``unbecome`` in action:
+The other way of using :meth:`become` does not replace but add to the top of
+the behavior stack. In this case care must be taken to ensure that the number
+of “pop” operations (i.e. :meth:`unbecome`) matches the number of “push” ones
+in the long run, otherwise this amounts to a memory leak (which is why this
+behavior is not the default). 
 
 .. includecode:: code/docs/actor/ActorDocSpec.scala#swapper
 
 Encoding Scala Actors nested receives without accidentally leaking memory
 -------------------------------------------------------------------------
 
-See this `Unnested receive example <https://github.com/akka/akka/blob/master/akka-docs/scala/code/docs/actor/UnnestedReceives.scala>`_.
+See this `Unnested receive example <@github@/akka-docs/rst/scala/code/docs/actor/UnnestedReceives.scala>`_.
-
-
-Downgrade
----------
-
-Since the hotswapped code is pushed to a Stack you can downgrade the code as
-well, all you need to do is to: Invoke the ``context.unbecome`` method from within the Actor.
-
-This will pop the Stack and replace the Actor's implementation with the
-``PartialFunction[Any, Unit]`` that is at the top of the Stack.
-
-Here's how you use the ``unbecome`` method:
-
-.. code-block:: scala
-
-  def receive = {
-    case "revert" => context.unbecome()
-  }
 
 
 Stash
@@ -752,9 +750,11 @@ major impact on performance.
   callback. This means it's not possible to write
   ``Actor with MyActor with Stash`` if ``MyActor`` overrides ``preRestart``.
 
-Note that the stash is not persisted across restarts of an actor,
+Note that the stash is part of the ephemeral actor state, unlike the
-unlike the actor's mailbox. Therefore, it should be managed like other
+mailbox. Therefore, it should be managed like other parts of the
-parts of the actor's state which have the same property.
+actor's state which have the same property. The :class:`Stash` trait’s
+implementation of :meth:`preRestart` will call ``unstashAll()``, which is
+usually the desired behavior.
 
 
 Killing an Actor

akka-docs/rst/scala/code/docs/actor/ActorDocSpec.scala

@@ -96,11 +96,11 @@ class Swapper extends Actor {
   def receive = {
     case Swap ⇒
       log.info("Hi")
-      become {
+      become({
         case Swap ⇒
           log.info("Ho")
           unbecome() // resets the latest 'become' (just for fun)
-      }
+      }, discardOld = false) // push on top instead of replace
   }
 }
 
@@ -316,13 +316,13 @@ class ActorDocSpec extends AkkaSpec(Map("akka.loglevel" -> "INFO")) {
       def receive = {
         case "open" ⇒
           unstashAll()
-          context.become {
+          context.become({
             case "write" ⇒ // do writing...
             case "close" ⇒
               unstashAll()
               context.unbecome()
             case msg ⇒ stash()
-          }
+          }, discardOld = false) // stack on top instead of replacing
         case msg ⇒ stash()
       }
     }

akka-docs/rst/scala/code/docs/actor/FSMDocSpec.scala

@@ -8,6 +8,7 @@ import language.postfixOps
 import akka.testkit.{ AkkaSpec ⇒ MyFavoriteTestFrameWorkPlusAkkaTestKit }
 //#test-code
 import akka.actor.Props
+import scala.collection.immutable
 
 class FSMDocSpec extends MyFavoriteTestFrameWorkPlusAkkaTestKit {
 
@@ -24,7 +25,7 @@ class FSMDocSpec extends MyFavoriteTestFrameWorkPlusAkkaTestKit {
     case object Flush
 
     // sent events
-    case class Batch(obj: Seq[Any])
+    case class Batch(obj: immutable.Seq[Any])
     //#simple-events
     //#simple-state
     // states
@@ -34,7 +35,7 @@ class FSMDocSpec extends MyFavoriteTestFrameWorkPlusAkkaTestKit {
 
     sealed trait Data
     case object Uninitialized extends Data
-    case class Todo(target: ActorRef, queue: Seq[Any]) extends Data
+    case class Todo(target: ActorRef, queue: immutable.Seq[Any]) extends Data
     //#simple-state
     //#simple-fsm
     class Buncher extends Actor with FSM[State, Data] {
@@ -193,12 +194,12 @@ class FSMDocSpec extends MyFavoriteTestFrameWorkPlusAkkaTestKit {
       buncher ! SetTarget(testActor)
       buncher ! Queue(42)
       buncher ! Queue(43)
-      expectMsg(Batch(Seq(42, 43)))
+      expectMsg(Batch(immutable.Seq(42, 43)))
       buncher ! Queue(44)
       buncher ! Flush
       buncher ! Queue(45)
-      expectMsg(Batch(Seq(44)))
+      expectMsg(Batch(immutable.Seq(44)))
-      expectMsg(Batch(Seq(45)))
+      expectMsg(Batch(immutable.Seq(45)))
     }
 
     "batch not if uninitialized" in {

akka-docs/rst/scala/code/docs/dataflow/DataflowDocSpec.scala

@@ -44,21 +44,23 @@ class DataflowDocSpec extends WordSpec with MustMatchers {
   }
 
   "demonstrate the use of dataflow variables" in {
-    def println[T](any: Try[T]): Unit = any.get must be === 20
+    val result = Promise[Int]()
+    def println(any: Try[Int]): Unit = result.complete(any)
     //#dataflow-variable-a
+    val v1, v2 = Promise[Int]()
     flow {
-      val v1, v2 = Promise[Int]()
-
       // v1 will become the value of v2 + 10 when v2 gets a value
       v1 << v2() + 10
-      v2 << flow { 5 } // As you can see, no blocking!
       v1() + v2()
     } onComplete println
+    flow { v2 << 5 } // As you can see, no blocking above!
     //#dataflow-variable-a
+    Await.result(result.future, 10.seconds) must be === 20
   }
 
   "demonstrate the difference between for and flow" in {
-    def println[T](any: Try[T]): Unit = any.get must be === 2
+    val result = Promise[Int]()
+    def println(any: Try[Int]): Unit = result.tryComplete(any)
     //#for-vs-flow
     val f1, f2 = Future { 1 }
 
@@ -68,6 +70,7 @@ class DataflowDocSpec extends WordSpec with MustMatchers {
     usingFor onComplete println
     usingFlow onComplete println
     //#for-vs-flow
+    Await.result(result.future, 10.seconds) must be === 2
   }
 
 }

akka-docs/rst/scala/code/docs/testkit/TestKitUsageSpec.scala

@@ -22,6 +22,7 @@ import akka.testkit.DefaultTimeout
 import akka.testkit.ImplicitSender
 import akka.testkit.TestKit
 import scala.concurrent.duration._
+import scala.collection.immutable
 
 /**
  * a Test to show some TestKit examples
@@ -38,8 +39,8 @@ class TestKitUsageSpec
   val filterRef = system.actorOf(Props(new FilteringActor(testActor)))
   val randomHead = Random.nextInt(6)
   val randomTail = Random.nextInt(10)
-  val headList = Seq().padTo(randomHead, "0")
+  val headList = immutable.Seq().padTo(randomHead, "0")
-  val tailList = Seq().padTo(randomTail, "1")
+  val tailList = immutable.Seq().padTo(randomTail, "1")
   val seqRef =
     system.actorOf(Props(new SequencingActor(testActor, headList, tailList)))
 
@@ -145,7 +146,7 @@ object TestKitUsageSpec {
    * like to test that the interesting value is received and that you cant
    * be bothered with the rest
    */
-  class SequencingActor(next: ActorRef, head: Seq[String], tail: Seq[String])
+  class SequencingActor(next: ActorRef, head: immutable.Seq[String], tail: immutable.Seq[String])
     extends Actor {
     def receive = {
       case msg ⇒ {

akka-docs/rst/scala/code/docs/zeromq/ZeromqDocSpec.scala

@@ -5,13 +5,13 @@ package docs.zeromq
 
 import language.postfixOps
 
-import akka.actor.{ Actor, Props }
 import scala.concurrent.duration._
+import scala.collection.immutable
+import akka.actor.{ Actor, Props }
 import akka.testkit._
-import akka.zeromq.{ ZeroMQVersion, ZeroMQExtension }
+import akka.zeromq.{ ZeroMQVersion, ZeroMQExtension, SocketType, Bind }
 import java.text.SimpleDateFormat
 import java.util.Date
-import akka.zeromq.{ SocketType, Bind }
 
 object ZeromqDocSpec {
 
@@ -52,12 +52,12 @@ object ZeromqDocSpec {
         val heapPayload = ser.serialize(Heap(timestamp, currentHeap.getUsed,
           currentHeap.getMax)).get
         // the first frame is the topic, second is the message
-        pubSocket ! ZMQMessage(Seq(Frame("health.heap"), Frame(heapPayload)))
+        pubSocket ! ZMQMessage(immutable.Seq(Frame("health.heap"), Frame(heapPayload)))
 
         // use akka SerializationExtension to convert to bytes
         val loadPayload = ser.serialize(Load(timestamp, os.getSystemLoadAverage)).get
         // the first frame is the topic, second is the message
-        pubSocket ! ZMQMessage(Seq(Frame("health.load"), Frame(loadPayload)))
+        pubSocket ! ZMQMessage(immutable.Seq(Frame("health.load"), Frame(loadPayload)))
     }
   }
   //#health
@@ -146,7 +146,7 @@ class ZeromqDocSpec extends AkkaSpec("akka.loglevel=INFO") {
 
     val payload = Array.empty[Byte]
     //#pub-topic
-    pubSocket ! ZMQMessage(Seq(Frame("foo.bar"), Frame(payload)))
+    pubSocket ! ZMQMessage(Frame("foo.bar"), Frame(payload))
     //#pub-topic
 
     system.stop(subSocket)

akka-docs/rst/scala/fsm.rst

@@ -124,6 +124,14 @@ obvious that an actor is actually created:
    :include: simple-fsm
    :exclude: fsm-body
 
+.. note::
+
+   The FSM trait defines a ``receive`` method which handles internal messages
+   and passes everything else through to the FSM logic (according to the
+   current state). When overriding the ``receive`` method, keep in mind that
+   e.g. state timeout handling depends on actually passing the messages through
+   the FSM logic.
+
 The :class:`FSM` trait takes two type parameters:
 
  #. the supertype of all state names, usually a sealed trait with case objects

akka-docs/rst/scala/testing.rst

@@ -713,8 +713,8 @@ Some `Specs2 <http://specs2.org>`_ users have contributed examples of how to wor
   actually beneficial also for the third point—is to apply the TestKit together
   with :class:`org.specs2.specification.Scope`.
 * The Specification traits provide a :class:`Duration` DSL which uses partly
-  the same method names as :class:`scala.concurrent.util.Duration`, resulting in ambiguous
+  the same method names as :class:`scala.concurrent.duration.Duration`, resulting in ambiguous
-  implicits if ``akka.util.duration._`` is imported. There are two work-arounds:
+  implicits if ``scala.concurrent.duration._`` is imported. There are two work-arounds:
 
   * either use the Specification variant of Duration and supply an implicit
     conversion to the Akka Duration. This conversion is not supplied with the