!pro #17380 Build with Java 8

* genjavadoc adjustments for java8

akka-docs/rst/scala/code/docs/io/ScalaUdpMulticastSpec.scala

@@ -0,0 +1,59 @@
+/**
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package docs.io
+
+import java.net.{ Inet6Address, InetSocketAddress, NetworkInterface, StandardProtocolFamily }
+import java.nio.channels.DatagramChannel
+import scala.util.Random
+
+import akka.actor.{ ActorSystem, Props }
+import akka.io.Udp
+import akka.testkit.TestKit
+import org.scalatest.{ BeforeAndAfter, WordSpecLike }
+
+import scala.collection.JavaConversions.enumerationAsScalaIterator
+
+class ScalaUdpMulticastSpec extends TestKit(ActorSystem("ScalaUdpMulticastSpec")) with WordSpecLike with BeforeAndAfter {
+
+  "listener" should {
+    "send message back to sink" in {
+      val Some(ipv6Iface) = NetworkInterface.getNetworkInterfaces.collectFirst {
+        case iface if iface.getInetAddresses.exists(_.isInstanceOf[Inet6Address]) => iface
+      }
+
+      // host assigned link local multicast address http://tools.ietf.org/html/rfc3307#section-4.3.2
+      // generate a random 32 bit multicast address with the high order bit set
+      val randomAddress: String = (Random.nextInt().abs.toLong | (1L << 31)).toHexString.toUpperCase
+      val group = randomAddress.grouped(4).mkString("FF02::", ":", "")
+      val port = TestUtils.temporaryUdpIpv6Port(ipv6Iface)
+      val msg = "ohi"
+      val sink = testActor
+      val iface = ipv6Iface.getName
+
+      val listener = system.actorOf(Props(classOf[Listener], iface, group, port, sink))
+      expectMsgType[Udp.Bound]
+      val sender = system.actorOf(Props(classOf[Sender], iface, group, port, msg))
+      expectMsg(msg)
+
+      // unbind
+      system.stop(listener)
+    }
+  }
+
+  def afterAll(): Unit = {
+    TestKit.shutdownActorSystem(system)
+  }
+
+}
+
+object TestUtils {
+  def temporaryUdpIpv6Port(iface: NetworkInterface) = {
+    val serverSocket = DatagramChannel.open(StandardProtocolFamily.INET6).socket()
+    serverSocket.bind(new InetSocketAddress(iface.getInetAddresses.nextElement(), 0))
+    val port = serverSocket.getLocalPort
+    serverSocket.close()
+    port
+  }
+}