diff --git a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
index 0b8e68c56a..c5595212c2 100644
--- a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
+++ b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
@@ -428,9 +428,7 @@ abstract class ExtendedActorSystem extends ActorSystem {
   def dynamicAccess: DynamicAccess
 }
 
-//FIXME This should most probably not be protected[akka] right? - √
-//FIXME We also need to decide whether this should be supported API or not - √
-class ActorSystemImpl protected[akka] (val name: String, applicationConfig: Config, classLoader: ClassLoader) extends ExtendedActorSystem {
+private[akka] class ActorSystemImpl(val name: String, applicationConfig: Config, classLoader: ClassLoader) extends ExtendedActorSystem {
 
   if (!name.matches("""^[a-zA-Z0-9][a-zA-Z0-9-]*$"""))
     throw new IllegalArgumentException(
diff --git a/akka-actor/src/main/scala/akka/actor/Address.scala b/akka-actor/src/main/scala/akka/actor/Address.scala
index 67f147b836..44c12eed35 100644
--- a/akka-actor/src/main/scala/akka/actor/Address.scala
+++ b/akka-actor/src/main/scala/akka/actor/Address.scala
@@ -114,7 +114,9 @@ object AddressFromURIString {
   def parse(addr: String): Address = apply(addr)
 }
 
-//FIXME is this public API? - √
+/**
+ * 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])] =
     try {
diff --git a/akka-actor/src/main/scala/akka/actor/FaultHandling.scala b/akka-actor/src/main/scala/akka/actor/FaultHandling.scala
index 8641153476..27a9f346db 100644
--- a/akka-actor/src/main/scala/akka/actor/FaultHandling.scala
+++ b/akka-actor/src/main/scala/akka/actor/FaultHandling.scala
@@ -165,7 +165,7 @@ object SupervisorStrategy extends SupervisorStrategyLowPriorityImplicits {
   def makeDecider(flat: Iterable[CauseDirective]): Decider = {
     val directives = sort(flat)
 
-    { case x ⇒ directives find (_._1 isInstance x) map (_._2) getOrElse Escalate }
+    { case x ⇒ directives collectFirst { case (c, d) if c isInstance x ⇒ d } getOrElse Escalate }
   }
 
   /**
diff --git a/akka-actor/src/main/scala/akka/actor/IO.scala b/akka-actor/src/main/scala/akka/actor/IO.scala
index 63eb2e4b3a..07af4213fc 100644
--- a/akka-actor/src/main/scala/akka/actor/IO.scala
+++ b/akka-actor/src/main/scala/akka/actor/IO.scala
@@ -320,7 +320,7 @@ object IO {
   }
 
   object Chunk {
-    val empty = new Chunk(ByteString.empty)
+    val empty: Chunk = new Chunk(ByteString.empty)
   }
 
   /**
@@ -344,7 +344,7 @@ object IO {
    * Iteratee.recover() in order to handle it properly.
    */
   case class EOF(cause: Option[Exception]) extends Input {
-    final override def ++(that: Input) = that
+    final override def ++(that: Input): Input = that
   }
 
   object Iteratee {
diff --git a/akka-actor/src/main/scala/akka/event/Logging.scala b/akka-actor/src/main/scala/akka/event/Logging.scala
index 58aa6aadf4..6e6f92ad0d 100644
--- a/akka-actor/src/main/scala/akka/event/Logging.scala
+++ b/akka-actor/src/main/scala/akka/event/Logging.scala
@@ -276,9 +276,9 @@ object LogSource {
 
   // this one unfortunately does not work as implicit, because existential types have some weird behavior
   val fromClass: LogSource[Class[_]] = new LogSource[Class[_]] {
-    def genString(c: Class[_]) = Logging.simpleName(c)
-    override def genString(c: Class[_], system: ActorSystem) = genString(c) + "(" + system + ")"
-    override def getClazz(c: Class[_]) = c
+    def genString(c: Class[_]): String = Logging.simpleName(c)
+    override def genString(c: Class[_], system: ActorSystem): String = genString(c) + "(" + system + ")"
+    override def getClazz(c: Class[_]): Class[_] = c
   }
   implicit def fromAnyClass[T]: LogSource[Class[T]] = fromClass.asInstanceOf[LogSource[Class[T]]]
 
diff --git a/akka-docs/general/actor-systems.rst b/akka-docs/general/actor-systems.rst
index 2051f2d845..1b7d6a7759 100644
--- a/akka-docs/general/actor-systems.rst
+++ b/akka-docs/general/actor-systems.rst
@@ -14,6 +14,11 @@ which means that we need not concern ourselves with their emotional state or
 moral issues). The result can then serve as a mental scaffolding for building
 the software implementation.
 
+.. note::
+
+   An ActorSystem is a heavyweight structure that will allocate 1…N Threads,
+   so create one per logical application.
+
 Hierarchical Structure
 ----------------------