add ActorRef.noSender() for the Java API, see #3429

- Actor.noSender is not accessible from Java, but it was in 2.1 so don’t
  remove
- replaced all “null” in doc tests with ActorRef.noSender()

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

@@ -189,11 +189,11 @@ public class FSMDocTest {
   public void mustBunch() {
     final ActorRef buncher = system.actorOf(Props.create(MyFSM.class));
     final TestProbe probe = new TestProbe(system);
-    buncher.tell(new SetTarget(probe.ref()), null);
-    buncher.tell(new Queue(1), null);
-    buncher.tell(new Queue(2), null);
-    buncher.tell(flush, null);
-    buncher.tell(new Queue(3), null);
+    buncher.tell(new SetTarget(probe.ref()), ActorRef.noSender());
+    buncher.tell(new Queue(1), ActorRef.noSender());
+    buncher.tell(new Queue(2), ActorRef.noSender());
+    buncher.tell(flush, ActorRef.noSender());
+    buncher.tell(new Queue(3), ActorRef.noSender());
     final Batch b = probe.expectMsgClass(Batch.class);
     assert b.objects.size() == 2;
     assert b.objects.contains(1);

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

@@ -179,21 +179,21 @@ public class FaultHandlingTest {
     //#create
 
     //#resume
-    child.tell(42, null);
+    child.tell(42, ActorRef.noSender());
     assert Await.result(ask(child, "get", 5000), timeout).equals(42);
-    child.tell(new ArithmeticException(), null);
+    child.tell(new ArithmeticException(), ActorRef.noSender());
     assert Await.result(ask(child, "get", 5000), timeout).equals(42);
     //#resume
 
     //#restart
-    child.tell(new NullPointerException(), null);
+    child.tell(new NullPointerException(), ActorRef.noSender());
     assert Await.result(ask(child, "get", 5000), timeout).equals(0);
     //#restart
 
     //#stop
     final TestProbe probe = new TestProbe(system);
     probe.watch(child);
-    child.tell(new IllegalArgumentException(), null);
+    child.tell(new IllegalArgumentException(), ActorRef.noSender());
     probe.expectMsgClass(Terminated.class);
     //#stop
 
@@ -202,7 +202,7 @@ public class FaultHandlingTest {
       Props.create(Child.class), 5000), timeout);
     probe.watch(child);
     assert Await.result(ask(child, "get", 5000), timeout).equals(0);
-    child.tell(new Exception(), null);
+    child.tell(new Exception(), ActorRef.noSender());
     probe.expectMsgClass(Terminated.class);
     //#escalate-kill
 
@@ -211,9 +211,9 @@ public class FaultHandlingTest {
     supervisor = system.actorOf(superprops);
     child = (ActorRef) Await.result(ask(supervisor,
       Props.create(Child.class), 5000), timeout);
-    child.tell(23, null);
+    child.tell(23, ActorRef.noSender());
     assert Await.result(ask(child, "get", 5000), timeout).equals(23);
-    child.tell(new Exception(), null);
+    child.tell(new Exception(), ActorRef.noSender());
     assert Await.result(ask(child, "get", 5000), timeout).equals(0);
     //#escalate-restart
     //#testkit

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

@@ -16,6 +16,6 @@ public class FirstUntypedActor extends UntypedActor {
 
   public void onReceive(Object message) {
     myActor.forward(message, getContext());
-    myActor.tell(PoisonPill.getInstance(), null);
+    myActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
   }
 }

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

@@ -49,7 +49,7 @@ public class InboxDocTest {
     //#watch
     final Inbox inbox = Inbox.create(system);
     inbox.watch(target);
-    target.tell(PoisonPill.getInstance(), null);
+    target.tell(PoisonPill.getInstance(), ActorRef.noSender());
     assert inbox.receive(Duration.create(1, TimeUnit.SECONDS)) instanceof Terminated;
     //#watch
   }

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

@@ -41,7 +41,7 @@ public class SchedulerDocTest {
       new Runnable() {
         @Override
         public void run() {
-          testActor.tell(System.currentTimeMillis(), null);
+          testActor.tell(System.currentTimeMillis(), ActorRef.noSender());
         }
     }, system.dispatcher());
     //#schedule-one-off-thunk

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

@@ -370,7 +370,7 @@ public class UntypedActorDocTest {
         master.tell("", getRef());
         final ActorRef victim = expectMsgClass(ActorRef.class);
         //#kill
-        victim.tell(akka.actor.Kill.getInstance(), null);
+        victim.tell(akka.actor.Kill.getInstance(), ActorRef.noSender());
         //#kill
         expectMsgEquals("killed");
         expectMsgEquals("stopped");

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

@@ -44,12 +44,12 @@ public class UntypedActorSwapper {
   public static void main(String... args) {
     ActorSystem system = ActorSystem.create("MySystem");
     ActorRef swap = system.actorOf(Props.create(Swapper.class));
-    swap.tell(SWAP, null); // logs Hi
-    swap.tell(SWAP, null); // logs Ho
-    swap.tell(SWAP, null); // logs Hi
-    swap.tell(SWAP, null); // logs Ho
-    swap.tell(SWAP, null); // logs Hi
-    swap.tell(SWAP, null); // logs Ho
+    swap.tell(SWAP, ActorRef.noSender()); // logs Hi
+    swap.tell(SWAP, ActorRef.noSender()); // logs Ho
+    swap.tell(SWAP, ActorRef.noSender()); // logs Hi
+    swap.tell(SWAP, ActorRef.noSender()); // logs Ho
+    swap.tell(SWAP, ActorRef.noSender()); // logs Hi
+    swap.tell(SWAP, ActorRef.noSender()); // logs Ho
   }
 
 }

akka-docs/rst/java/code/docs/actor/mailbox/DurableMailboxDocTest.java

@@ -33,7 +33,7 @@ public class DurableMailboxDocTest {
     ActorRef myActor = system.actorOf(Props.create(MyUntypedActor.class).
         withDispatcher("my-dispatcher"), "myactor");
     //#dispatcher-config-use
-    myActor.tell("test", null);
+    myActor.tell("test", ActorRef.noSender());
   }
 
   public static class MyUntypedActor extends UntypedActor {