diff --git a/akka-actor-tests/src/test/scala/akka/routing/ConfiguredLocalRoutingSpec.scala b/akka-actor-tests/src/test/scala/akka/routing/ConfiguredLocalRoutingSpec.scala
index d01f1cda04..5bedc8fc33 100644
--- a/akka-actor-tests/src/test/scala/akka/routing/ConfiguredLocalRoutingSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/routing/ConfiguredLocalRoutingSpec.scala
@@ -8,7 +8,7 @@ import java.util.concurrent.atomic.AtomicInteger
 import org.junit.runner.RunWith
 
 import akka.actor.{ Props, LocalActorRef, Deploy, Actor, ActorRef }
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import akka.dispatch.Await
 import akka.pattern.{ ask, gracefulStop }
 import akka.testkit.{ TestLatch, ImplicitSender, DefaultTimeout, AkkaSpec }
diff --git a/akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala b/akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala
index 2ae32cfcf5..5ad6da271f 100644
--- a/akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala
@@ -10,7 +10,7 @@ import akka.testkit._
 import akka.util.duration._
 import akka.dispatch.Await
 import akka.util.Duration
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import com.typesafe.config.ConfigFactory
 import akka.pattern.ask
 import java.util.concurrent.ConcurrentHashMap
diff --git a/akka-actor/src/main/scala/akka/AkkaException.scala b/akka-actor/src/main/scala/akka/AkkaException.scala
index 002233ffe5..79d78b9d39 100644
--- a/akka-actor/src/main/scala/akka/AkkaException.scala
+++ b/akka-actor/src/main/scala/akka/AkkaException.scala
@@ -44,3 +44,10 @@ class AkkaException(message: String = "", cause: Throwable = null) extends Runti
 
   def stackTraceToString = AkkaException.stackTraceToString(this)
 }
+
+/**
+ * This exception is thrown when Akka detects a problem with the provided configuration
+ */
+class ConfigurationException(message: String, cause: Throwable = null) extends AkkaException(message, cause) {
+  def this(msg: String) = this(msg, null)
+}
diff --git a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
index 32e221a7a1..a1d30ddbc6 100644
--- a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
+++ b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
@@ -4,7 +4,6 @@
 
 package akka.actor
 
-import akka.config.ConfigurationException
 import akka.event._
 import akka.dispatch._
 import akka.pattern.ask
@@ -150,7 +149,7 @@ object ActorSystem {
     final val JvmExitOnFatalError = getBoolean("akka.jvm-exit-on-fatal-error")
 
     if (ConfigVersion != Version)
-      throw new ConfigurationException("Akka JAR version [" + Version + "] does not match the provided config version [" + ConfigVersion + "]")
+      throw new akka.ConfigurationException("Akka JAR version [" + Version + "] does not match the provided config version [" + ConfigVersion + "]")
 
     /**
      * Returns the String representation of the Config that this Settings is backed by
diff --git a/akka-actor/src/main/scala/akka/config/ConfigurationException.scala b/akka-actor/src/main/scala/akka/config/ConfigurationException.scala
deleted file mode 100644
index ba0a3a2234..0000000000
--- a/akka-actor/src/main/scala/akka/config/ConfigurationException.scala
+++ /dev/null
@@ -1,15 +0,0 @@
-/**
- * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
- */
-
-package akka.config
-
-import akka.AkkaException
-
-class ConfigurationException(message: String, cause: Throwable = null) extends AkkaException(message, cause) {
-  def this(msg: String) = this(msg, null);
-}
-
-class ModuleNotAvailableException(message: String, cause: Throwable = null) extends AkkaException(message, cause) {
-  def this(msg: String) = this(msg, null);
-}
diff --git a/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala b/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
index db5c71167b..9aec23b4c6 100644
--- a/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
+++ b/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
@@ -33,7 +33,10 @@ final case class Envelope(val message: Any, val sender: ActorRef)(system: ActorS
   }
 }
 
-object SystemMessage {
+/**
+ * INTERNAL API
+ */
+private[akka] object SystemMessage {
   @tailrec
   final def size(list: SystemMessage, acc: Int = 0): Int = {
     if (list eq null) acc else size(list.next, acc + 1)
@@ -59,33 +62,57 @@ object SystemMessage {
  * system messages is handled in a single thread only and not ever passed around,
  * hence no further synchronization is needed.
  *
+ * INTERNAL API
+ *
  * ➡➡➡ NEVER SEND THE SAME SYSTEM MESSAGE OBJECT TO TWO ACTORS ⬅⬅⬅
  */
-sealed trait SystemMessage extends PossiblyHarmful {
+private[akka] sealed trait SystemMessage extends PossiblyHarmful {
   @transient
   var next: SystemMessage = _
 }
-case class Create() extends SystemMessage // send to self from Dispatcher.register
-case class Recreate(cause: Throwable) extends SystemMessage // sent to self from ActorCell.restart
-case class Suspend() extends SystemMessage // sent to self from ActorCell.suspend
-case class Resume() extends SystemMessage // sent to self from ActorCell.resume
-case class Terminate() extends SystemMessage // sent to self from ActorCell.stop
-case class Supervise(child: ActorRef) extends SystemMessage // sent to supervisor ActorRef from ActorCell.start
-case class ChildTerminated(child: ActorRef) extends SystemMessage // sent to supervisor from ActorCell.doTerminate
-case class Link(subject: ActorRef) extends SystemMessage // sent to self from ActorCell.watch
-case class Unlink(subject: ActorRef) extends SystemMessage // sent to self from ActorCell.unwatch
+
+/**
+ * INTERNAL API
+ */
+private[akka] case class Create() extends SystemMessage // send to self from Dispatcher.register
+/**
+ * INTERNAL API
+ */
+private[akka] case class Recreate(cause: Throwable) extends SystemMessage // sent to self from ActorCell.restart
+/**
+ * INTERNAL API
+ */
+private[akka] case class Suspend() extends SystemMessage // sent to self from ActorCell.suspend
+/**
+ * INTERNAL API
+ */
+private[akka] case class Resume() extends SystemMessage // sent to self from ActorCell.resume
+/**
+ * INTERNAL API
+ */
+private[akka] case class Terminate() extends SystemMessage // sent to self from ActorCell.stop
+/**
+ * INTERNAL API
+ */
+private[akka] case class Supervise(child: ActorRef) extends SystemMessage // sent to supervisor ActorRef from ActorCell.start
+/**
+ * INTERNAL API
+ */
+private[akka] case class ChildTerminated(child: ActorRef) extends SystemMessage // sent to supervisor from ActorCell.doTerminate
+/**
+ * INTERNAL API
+ */
+private[akka] case class Link(subject: ActorRef) extends SystemMessage // sent to self from ActorCell.watch
+/**
+ * INTERNAL API
+ */
+private[akka] case class Unlink(subject: ActorRef) extends SystemMessage // sent to self from ActorCell.unwatch
 
 final case class TaskInvocation(eventStream: EventStream, runnable: Runnable, cleanup: () ⇒ Unit) extends Runnable {
-  def run() {
-    try {
-      runnable.run()
-    } catch {
-      case NonFatal(e) ⇒
-        eventStream.publish(Error(e, "TaskInvocation", this.getClass, e.getMessage))
-    } finally {
-      cleanup()
-    }
-  }
+  def run(): Unit =
+    try runnable.run() catch {
+      case NonFatal(e) ⇒ eventStream.publish(Error(e, "TaskInvocation", this.getClass, e.getMessage))
+    } finally cleanup()
 }
 
 /**
@@ -170,10 +197,16 @@ trait ExecutionContext {
   def reportFailure(t: Throwable): Unit
 }
 
+/**
+ * INTERNAL API
+ */
 private[akka] trait LoadMetrics { self: Executor ⇒
   def atFullThrottle(): Boolean
 }
 
+/**
+ * INTERNAL API
+ */
 private[akka] object MessageDispatcher {
   val UNSCHEDULED = 0 //WARNING DO NOT CHANGE THE VALUE OF THIS: It relies on the faster init of 0 in AbstractMessageDispatcher
   val SCHEDULED = 1
@@ -228,7 +261,7 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
   /**
    *  Creates and returns a mailbox for the given actor.
    */
-  protected[akka] def createMailbox(actor: ActorCell): Mailbox
+  protected[akka] def createMailbox(actor: ActorCell): Mailbox //FIXME should this really be private[akka]?
 
   /**
    * Identifier of this dispatcher, corresponds to the full key
@@ -255,7 +288,7 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
     ifSensibleToDoSoThenScheduleShutdown()
   }
 
-  final def execute(runnable: Runnable) {
+  final def execute(runnable: Runnable): Unit = {
     val invocation = TaskInvocation(eventStream, runnable, taskCleanup)
     addInhabitants(+1)
     try {
@@ -300,6 +333,8 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
 
   /**
    * If you override it, you must call it. But only ever once. See "attach" for only invocation.
+   *
+   * INTERNAL API
    */
   protected[akka] def register(actor: ActorCell) {
     if (debug) actors.put(this, actor.self)
@@ -308,6 +343,8 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
 
   /**
    * If you override it, you must call it. But only ever once. See "detach" for the only invocation
+   *
+   * INTERNAL API
    */
   protected[akka] def unregister(actor: ActorCell) {
     if (debug) actors.remove(this, actor.self)
@@ -340,6 +377,8 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
    * When the dispatcher no longer has any actors registered, how long will it wait until it shuts itself down,
    * defaulting to your akka configs "akka.actor.default-dispatcher.shutdown-timeout" or default specified in
    * reference.conf
+   *
+   * INTERNAL API
    */
   protected[akka] def shutdownTimeout: Duration
 
@@ -362,36 +401,59 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
   }
 
   /**
-   *   Will be called when the dispatcher is to queue an invocation for execution
+   * Will be called when the dispatcher is to queue an invocation for execution
+   *
+   * INTERNAL API
    */
   protected[akka] def systemDispatch(receiver: ActorCell, invocation: SystemMessage)
 
   /**
-   *   Will be called when the dispatcher is to queue an invocation for execution
+   * Will be called when the dispatcher is to queue an invocation for execution
+   *
+   * INTERNAL API
    */
   protected[akka] def dispatch(receiver: ActorCell, invocation: Envelope)
 
   /**
    * Suggest to register the provided mailbox for execution
+   *
+   * INTERNAL API
    */
   protected[akka] def registerForExecution(mbox: Mailbox, hasMessageHint: Boolean, hasSystemMessageHint: Boolean): Boolean
 
   // TODO check whether this should not actually be a property of the mailbox
+  /**
+   * INTERNAL API
+   */
   protected[akka] def throughput: Int
+
+  /**
+   * INTERNAL API
+   */
   protected[akka] def throughputDeadlineTime: Duration
 
-  @inline
-  protected[akka] final val isThroughputDeadlineTimeDefined = throughputDeadlineTime.toMillis > 0
+  /**
+   * INTERNAL API
+   */
+  @inline protected[akka] final val isThroughputDeadlineTimeDefined = throughputDeadlineTime.toMillis > 0
 
+  /**
+   * INTERNAL API
+   */
   protected[akka] def executeTask(invocation: TaskInvocation)
 
   /**
    * Called one time every time an actor is detached from this dispatcher and this dispatcher has no actors left attached
    * Must be idempotent
+   *
+   * INTERNAL API
    */
   protected[akka] def shutdown(): Unit
 }
 
+/**
+ * An ExecutorServiceConfigurator is a class that given some prerequisites and a configuration can create instances of ExecutorService
+ */
 abstract class ExecutorServiceConfigurator(config: Config, prerequisites: DispatcherPrerequisites) extends ExecutorServiceFactoryProvider
 
 /**
diff --git a/akka-actor/src/main/scala/akka/event/Logging.scala b/akka-actor/src/main/scala/akka/event/Logging.scala
index 2cda6469da..ac31b133b3 100644
--- a/akka-actor/src/main/scala/akka/event/Logging.scala
+++ b/akka-actor/src/main/scala/akka/event/Logging.scala
@@ -4,12 +4,10 @@
 package akka.event
 
 import akka.actor._
-import akka.AkkaException
+import akka.{ ConfigurationException, AkkaException }
 import akka.actor.ActorSystem.Settings
-import akka.config.ConfigurationException
-import akka.util.ReentrantGuard
+import akka.util.{ Timeout, ReentrantGuard }
 import akka.util.duration._
-import akka.util.Timeout
 import java.util.concurrent.atomic.AtomicInteger
 import scala.util.control.NoStackTrace
 import java.util.concurrent.TimeoutException
diff --git a/akka-actor/src/main/scala/akka/routing/Routing.scala b/akka-actor/src/main/scala/akka/routing/Routing.scala
index fdf14a5b96..211ef202f7 100644
--- a/akka-actor/src/main/scala/akka/routing/Routing.scala
+++ b/akka-actor/src/main/scala/akka/routing/Routing.scala
@@ -6,7 +6,7 @@ package akka.routing
 import akka.actor._
 import akka.util.Duration
 import akka.util.duration._
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import akka.pattern.pipe
 import akka.pattern.AskSupport
 import com.typesafe.config.Config
diff --git a/akka-actor/src/main/scala/akka/serialization/Serialization.scala b/akka-actor/src/main/scala/akka/serialization/Serialization.scala
index ce0f56a238..03d03dc785 100644
--- a/akka-actor/src/main/scala/akka/serialization/Serialization.scala
+++ b/akka-actor/src/main/scala/akka/serialization/Serialization.scala
@@ -85,7 +85,7 @@ class Serialization(val system: ExtendedActorSystem) extends Extension {
   /**
    * Returns the Serializer configured for the given object, returns the NullSerializer if it's null.
    *
-   * @throws akka.config.ConfigurationException if no `serialization-bindings` is configured for the
+   * @throws akka.ConfigurationException if no `serialization-bindings` is configured for the
    *   class of the object
    */
   def findSerializerFor(o: AnyRef): Serializer = o match {
diff --git a/akka-cluster/src/main/scala/akka/cluster/Cluster.scala b/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
index e3429cfdb3..76e3356143 100644
--- a/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
@@ -13,7 +13,7 @@ import akka.dispatch.Await
 import akka.pattern.ask
 import akka.util._
 import akka.util.duration._
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 
 import java.util.concurrent.atomic.{ AtomicReference, AtomicBoolean }
 import java.util.concurrent.TimeUnit._
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
index a24c75b436..8e9b9c770d 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
@@ -6,7 +6,7 @@ package akka.cluster
 import com.typesafe.config.Config
 import akka.util.Duration
 import java.util.concurrent.TimeUnit.MILLISECONDS
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import scala.collection.JavaConverters._
 import akka.actor.Address
 import akka.actor.AddressFromURIString
diff --git a/akka-durable-mailboxes/akka-file-mailbox/src/main/scala/akka/actor/mailbox/FileBasedMailbox.scala b/akka-durable-mailboxes/akka-file-mailbox/src/main/scala/akka/actor/mailbox/FileBasedMailbox.scala
index ef8a28b2cf..e57bfd57d2 100644
--- a/akka-durable-mailboxes/akka-file-mailbox/src/main/scala/akka/actor/mailbox/FileBasedMailbox.scala
+++ b/akka-durable-mailboxes/akka-file-mailbox/src/main/scala/akka/actor/mailbox/FileBasedMailbox.scala
@@ -11,7 +11,7 @@ import akka.actor.ActorRef
 import akka.dispatch.MailboxType
 import com.typesafe.config.Config
 import akka.util.NonFatal
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import akka.actor.ActorSystem
 
 class FileBasedMailboxType(systemSettings: ActorSystem.Settings, config: Config) extends MailboxType {
diff --git a/akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala b/akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala
index 8f1ec6e1b7..bf55edf24c 100644
--- a/akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala
+++ b/akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala
@@ -9,7 +9,7 @@ import akka.actor._
 import akka.dispatch._
 import akka.event.{ DeathWatch, Logging, LoggingAdapter }
 import akka.event.EventStream
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import java.util.concurrent.{ TimeoutException }
 import com.typesafe.config.Config
 import akka.serialization.Serialization
diff --git a/akka-remote/src/main/scala/akka/remote/RemoteDeployer.scala b/akka-remote/src/main/scala/akka/remote/RemoteDeployer.scala
index 0858c66405..e869c4ef4c 100644
--- a/akka-remote/src/main/scala/akka/remote/RemoteDeployer.scala
+++ b/akka-remote/src/main/scala/akka/remote/RemoteDeployer.scala
@@ -6,7 +6,7 @@ package akka.remote
 import akka.actor._
 import akka.routing._
 import com.typesafe.config._
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 
 case class RemoteScope(node: Address) extends Scope {
   def withFallback(other: Scope): Scope = this
diff --git a/akka-remote/src/main/scala/akka/remote/RemoteSettings.scala b/akka-remote/src/main/scala/akka/remote/RemoteSettings.scala
index ef30206a42..0b26311286 100644
--- a/akka-remote/src/main/scala/akka/remote/RemoteSettings.scala
+++ b/akka-remote/src/main/scala/akka/remote/RemoteSettings.scala
@@ -7,7 +7,7 @@ import com.typesafe.config.Config
 import akka.util.Duration
 import java.util.concurrent.TimeUnit.MILLISECONDS
 import java.net.InetAddress
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import scala.collection.JavaConverters._
 import akka.actor.Address
 import akka.actor.AddressFromURIString
diff --git a/akka-remote/src/main/scala/akka/remote/netty/Settings.scala b/akka-remote/src/main/scala/akka/remote/netty/Settings.scala
index e2f69d77b5..95737e7584 100644
--- a/akka-remote/src/main/scala/akka/remote/netty/Settings.scala
+++ b/akka-remote/src/main/scala/akka/remote/netty/Settings.scala
@@ -7,7 +7,7 @@ import com.typesafe.config.Config
 import akka.util.Duration
 import java.util.concurrent.TimeUnit._
 import java.net.InetAddress
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 
 class NettySettings(config: Config, val systemName: String) {
 
diff --git a/akka-remote/src/main/scala/akka/routing/RemoteRouterConfig.scala b/akka-remote/src/main/scala/akka/routing/RemoteRouterConfig.scala
index c9bb6dba0f..714b854a69 100644
--- a/akka-remote/src/main/scala/akka/routing/RemoteRouterConfig.scala
+++ b/akka-remote/src/main/scala/akka/routing/RemoteRouterConfig.scala
@@ -10,7 +10,7 @@ import akka.actor.ActorSystemImpl
 import akka.actor.Deploy
 import akka.actor.InternalActorRef
 import akka.actor.Props
-import akka.config.ConfigurationException
+import akka.ConfigurationException
 import akka.remote.RemoteScope
 import akka.actor.AddressFromURIString
 import akka.actor.SupervisorStrategy