diff --git a/akka-core/src/main/scala/actor/ActorRegistry.scala b/akka-core/src/main/scala/actor/ActorRegistry.scala
index 7ca40d1a82..9e0b1cba08 100644
--- a/akka-core/src/main/scala/actor/ActorRegistry.scala
+++ b/akka-core/src/main/scala/actor/ActorRegistry.scala
@@ -6,92 +6,123 @@ package se.scalablesolutions.akka.actor
 
 import se.scalablesolutions.akka.util.Logging
 
-import scala.collection.mutable.{ListBuffer, HashMap}
+import scala.collection.mutable.ListBuffer
 import scala.reflect.Manifest
 
+import java.util.concurrent.ConcurrentHashMap
+
 /**
- * Registry holding all actor instances, mapped by class, the actor's uuid and the actor's id field (which can be set
- * by user-code).
+ * Registry holding all Actor instances in the whole system.
+ * Mapped by:
+ * <ul>
+ * <li>the Actor's UUID</li>
+ * <li>the Actor's id field (which can be set by user-code)</li>
+ * <li>the Actor's class</li>
+ * <ul>
  *
  * @author <a href="http://jonasboner.com">Jonas Bon&#233;r</a>
  */
 object ActorRegistry extends Logging {
-  private val actorsByClassName = new HashMap[String, List[Actor]]
-  private val actorsById = new HashMap[String, List[Actor]]
-  private val actorsByUuid = new HashMap[String, Actor]
+  private val actorsByUUID =      new ConcurrentHashMap[String, Actor]
+  private val actorsById =        new ConcurrentHashMap[String, List[Actor]]
+  private val actorsByClassName = new ConcurrentHashMap[String, List[Actor]]
 
   /**
    * Returns all actors in the system.
    */
-  def actors: List[Actor] = synchronized {
+  def actors: List[Actor] = {
     val all = new ListBuffer[Actor]
-    actorsById.values.foreach(all ++= _)
+    val elements = actorsByUUID.elements
+    while (elements.hasMoreElements) all += elements.nextElement
     all.toList
   }
 
   /**
    * Invokes a function for all actors.
    */
-  def foreach(f: (Actor) => Unit) = actors.foreach(f)
+  def foreach(f: (Actor) => Unit) = {
+    val elements = actorsByUUID.elements
+    while (elements.hasMoreElements) f(elements.nextElement)
+  }
 
   /**
    * Finds all actors that are subtypes of the class passed in as the Manifest argument.
    */
-  def actorsFor[T <: Actor](implicit manifest: Manifest[T]): List[T] = synchronized {
-    for (actor <- actors; if manifest.erasure.isAssignableFrom(actor.getClass)) yield actor.asInstanceOf[T]
+  def actorsFor[T <: Actor](implicit manifest: Manifest[T]): List[T] = {
+    val all = new ListBuffer[T]
+    val elements = actorsByUUID.elements
+    while (elements.hasMoreElements) {
+      val actor = elements.nextElement
+      if (manifest.erasure.isAssignableFrom(actor.getClass)) {
+        all += actor.asInstanceOf[T]
+      }
+    }
+    all.toList
   }
 
   /**
    * Finds all actors of the exact type specified by the class passed in as the Class argument.
    */
-  def actorsFor[T <: Actor](clazz: Class[T]): List[T] = synchronized {
-    actorsByClassName.get(clazz.getName) match {
-      case None => Nil
-      case Some(instances) => instances.asInstanceOf[List[T]]
-    }
+  def actorsFor[T <: Actor](clazz: Class[T]): List[T] = {
+    if (actorsByClassName.containsKey(clazz.getName)) {
+      actorsByClassName.get(clazz.getName).asInstanceOf[List[T]]
+    } else Nil
   }
 
   /**
-   * Finds all actors that have a specific id.
+   * Finds all actors that has a specific id.
    */
-  def actorsFor(id : String): List[Actor] = synchronized {
-    actorsById.get(id) match {
-      case None => Nil
-      case Some(instances) => instances
-    }
+  def actorsFor(id: String): List[Actor] = {
+    if (actorsById.containsKey(id)) actorsById.get(id).asInstanceOf[List[Actor]]
+    else Nil
+  }
+
+   /**
+   * Finds the actor that has a specific UUID.
+   */
+  def actorFor(uuid: String): Option[Actor] = {
+    if (actorsByUUID.containsKey(uuid)) Some(actorsByUUID.get(uuid))
+    else None
   }
 
   /**
-   * Finds the actor that has a specific uuid.
+   * Registers an actor in the ActorRegistry.
    */
-  def actorFor(uuid : String): Option[Actor] = synchronized {
-    actorsByUuid.get(uuid)
-  }
+  def register(actor: Actor) = {
+    // UUID
+    actorsByUUID.put(actor.uuid, actor)
 
-  def register(actor: Actor) = synchronized {
-    val className = actor.getClass.getName
-    actorsByClassName.get(className) match {
-      case Some(instances) => actorsByClassName + (className -> (actor :: instances))
-      case None => actorsByClassName + (className -> (actor :: Nil))
-    }
+    // ID
     val id = actor.getId
     if (id eq null) throw new IllegalStateException("Actor.id is null " + actor)
-    actorsById.get(id) match {
-      case Some(instances) => actorsById + (id -> (actor :: instances))
-      case None => actorsById + (id -> (actor :: Nil))
-    }
-    actorsByUuid + (actor.uuid -> actor)
+    if (actorsById.containsKey(id)) actorsById.put(id, actor :: actorsById.get(id))
+    else actorsById.put(id, actor :: Nil)
+
+    // Class name
+    val className = actor.getClass.getName
+    if (actorsByClassName.containsKey(className)) {
+      actorsByClassName.put(className, actor :: actorsByClassName.get(className))
+    } else actorsByClassName.put(className, actor :: Nil)
   }
 
-  def unregister(actor: Actor) = synchronized {
-    actorsByClassName - actor.getClass.getName
-    actorsById - actor.getId
-    actorsByUuid - actor.uuid
+  /**
+   * Unregisters an actor in the ActorRegistry.
+   */
+  def unregister(actor: Actor) = {
+    actorsByUUID remove actor.uuid
+    actorsById remove actor.getId
+    actorsByClassName remove actor.getClass.getName
   }
 
+  /**
+   * Shuts down and unregisters all actors in the system.
+   */
   def shutdownAll = {
     log.info("Shutting down all actors in the system...")
-    actorsById.foreach(entry => entry._2.map(_.stop))
-    log.info("All actors have been shut down")
+    foreach(_.stop)
+    actorsByUUID.clear
+    actorsById.clear
+    actorsByClassName.clear
+    log.info("All actors have been shut down and unregistered from ActorRegistry")
   }
 }
diff --git a/akka-core/src/test/scala/ActorRegistryTest.scala b/akka-core/src/test/scala/ActorRegistryTest.scala
index 4c0292abcf..faa4a46b18 100644
--- a/akka-core/src/test/scala/ActorRegistryTest.scala
+++ b/akka-core/src/test/scala/ActorRegistryTest.scala
@@ -1,55 +1,160 @@
 package se.scalablesolutions.akka.actor
 
-import org.junit.Assert._
 import org.scalatest.junit.JUnitSuite
 import org.junit.Test
 
 class ActorRegistryTest extends JUnitSuite {
-
-  val registry = ActorRegistry
-
-  @Test
-  def testRegistrationWithDefaultId {
-    val actor = new TestActor1
-    assertEquals(actor.getClass.getName, actor.getId)
-    testRegistration(actor, classOf[TestActor1])
+  var record = ""
+  class TestActor extends Actor {
+    id = "MyID"
+    def receive = {
+      case "ping" =>
+        record = "pong" + record
+    }
   }
 
-  @Test
-  def testRegistrationWithCustomId {
-    val actor = new TestActor2
-    assertEquals("customid", actor.getId)
-    testRegistration(actor, classOf[TestActor2])
-  }
-
-  private def testRegistration[T <: Actor](actor: T, actorClass: Class[T]) {
-    assertEquals("non-started actor registered", Nil, registry.actorsFor(actorClass))
-    assertEquals("non-started actor registered", Nil, registry.actorsFor(actor.getId))
-    assertEquals("non-started actor registered", None, registry.actorFor(actor.uuid))
+  @Test def shouldGetActorByIdFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor = new TestActor
     actor.start
-    assertEquals("actor not registered", List(actor), registry.actorsFor(actorClass))
-    assertEquals("actor not registered", List(actor), registry.actorsFor(actor.getId))
-    assertEquals("actor not registered", Some(actor), registry.actorFor(actor.uuid))
+    val actors = ActorRegistry.actorsFor("MyID")
+    assert(actors.size === 1)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId == "MyID")
     actor.stop
-    assertEquals("stopped actor registered", Nil, registry.actorsFor(actorClass))
-    assertEquals("stopped actor registered", Nil, registry.actorsFor(actor.getId))
-    assertEquals("stopped actor registered", None, registry.actorFor(actor.uuid))
   }
 
+  @Test def shouldGetActorByUUIDFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor = new TestActor
+    val uuid = actor.uuid
+    actor.start
+    val actorOrNone = ActorRegistry.actorFor(uuid)
+    assert(actorOrNone.isDefined)
+    assert(actorOrNone.get.uuid === uuid)
+    actor.stop
+  }
+
+  @Test def shouldGetActorByClassFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor = new TestActor
+    actor.start
+    val actors = ActorRegistry.actorsFor(classOf[TestActor])
+    assert(actors.size === 1)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    actor.stop
+  }
+
+  @Test def shouldGetActorByManifestFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor = new TestActor
+    actor.start
+    val actors: List[TestActor] = ActorRegistry.actorsFor[TestActor]
+    assert(actors.size === 1)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    actor.stop
+  }
+
+  @Test def shouldGetActorsByIdFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    val actors = ActorRegistry.actorsFor("MyID")
+    assert(actors.size === 2)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    assert(actors.last.isInstanceOf[TestActor])
+    assert(actors.last.getId === "MyID")
+    actor1.stop
+    actor2.stop
+  }
+
+  @Test def shouldGetActorsByClassFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    val actors = ActorRegistry.actorsFor(classOf[TestActor])
+    assert(actors.size === 2)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    assert(actors.last.isInstanceOf[TestActor])
+    assert(actors.last.getId === "MyID")
+    actor1.stop
+    actor2.stop
+  }
+
+  @Test def shouldGetActorsByManifestFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    val actors: List[TestActor] = ActorRegistry.actorsFor[TestActor]
+    assert(actors.size === 2)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    assert(actors.last.isInstanceOf[TestActor])
+    assert(actors.last.getId === "MyID")
+    actor1.stop
+    actor2.stop
+  }
+
+  @Test def shouldGetAllActorsFromActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    val actors = ActorRegistry.actors
+    assert(actors.size === 2)
+    assert(actors.head.isInstanceOf[TestActor])
+    assert(actors.head.getId === "MyID")
+    assert(actors.last.isInstanceOf[TestActor])
+    assert(actors.last.getId === "MyID")
+    actor1.stop
+    actor2.stop
+  }
+
+  @Test def shouldGetResponseByAllActorsInActorRegistryWhenInvokingForeach = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    record = ""
+    ActorRegistry.foreach(actor => actor send "ping")
+    Thread.sleep(1000)
+    assert(record === "pongpong")
+    actor1.stop
+    actor2.stop
+  }
+
+  @Test def shouldShutdownAllActorsInActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    ActorRegistry.shutdownAll
+    assert(ActorRegistry.actors.size === 0)
+  }
+
+  @Test def shouldRemoveUnregisterActorInActorRegistry = {
+    ActorRegistry.shutdownAll
+    val actor1 = new TestActor
+    actor1.start
+    val actor2 = new TestActor
+    actor2.start
+    assert(ActorRegistry.actors.size === 2)
+    ActorRegistry.unregister(actor1)
+    assert(ActorRegistry.actors.size === 1)
+    ActorRegistry.unregister(actor2)
+    assert(ActorRegistry.actors.size === 0)
+  }
 }
-
-class TestActor1 extends Actor {
-
-  // use default id
-
-  protected def receive = null
-
-}
-
-class TestActor2 extends Actor {
-
-  id = "customid"
-
-  protected def receive = null
-
-}
\ No newline at end of file
diff --git a/akka-samples/akka-sample-chat/src/main/scala/ChatServer.scala b/akka-samples/akka-sample-chat/src/main/scala/ChatServer.scala
index f605fc7cba..d03c209706 100644
--- a/akka-samples/akka-sample-chat/src/main/scala/ChatServer.scala
+++ b/akka-samples/akka-sample-chat/src/main/scala/ChatServer.scala
@@ -76,11 +76,7 @@ trait ChatStorage extends Actor
 class RedisChatStorage extends ChatStorage {
   lifeCycle = Some(LifeCycle(Permanent))    
       
-  private var chatLog: PersistentVector[Array[Byte]] = _
-
-  override def initTransactionalState = chatLog = RedisStorage.getVector("akka.chat.log")
-
-  chatLog = RedisStorage.getVector("akka.chat.log")
+  private var chatLog = atomic { RedisStorage.getVector("akka.chat.log") }
 
   log.info("Redis-based chat storage is starting up...")