Please review below minor change for 8199931, thanks A little explanation about the change here, since the failure samples are too less (seems too hard to repro), so below scenario which caused the failure is a guess. MultcastSocket constructor set reuse address true by default, when call “new MulticastSocket(0)” to create client socket that maybe in a little possibility it used same address with server, that will explain why the failure looks like client received data package from itself. Follow the guessing, I modified test code to explicit create client socket use same port with server, then got same failure error as reported bug on OEL7. Though I cannot make sure the guess is 100% match with the original failure, but at least we could try to prevent such possible scenario.
bug: https://bugs.openjdk.java.net/browse/JDK-8199931 changes: diff -r 43668e3cae4d test/jdk/java/net/MulticastSocket/UnreferencedMulticastSockets.java --- a/test/jdk/java/net/MulticastSocket/UnreferencedMulticastSockets.java Thu Sep 20 08:59:03 2018 +0200 +++ b/test/jdk/java/net/MulticastSocket/UnreferencedMulticastSockets.java Thu Sep 20 16:37:36 2018 +0800 @@ -40,6 +40,7 @@ import java.net.DatagramSocket; import java.net.DatagramSocketImpl; import java.net.InetAddress; +import java.net.InetSocketAddress; import java.net.MulticastSocket; import java.net.UnknownHostException; import java.nio.file.Files; @@ -119,7 +120,10 @@ Thread thr = new Thread(svr); thr.start(); - MulticastSocket client = new MulticastSocket(0); + MulticastSocket client = new MulticastSocket(null); + // prevent MulticastSocket reuse previous address, see 8199931 + client.setReuseAddress(false); + client.bind(new InetSocketAddress(0)); client.connect(svr.getHost(), svr.getPort()); pendingSockets.add(new NamedWeak(client, pendingQueue, "clientMulticastSocket")); extractRefs(client, "clientMulticastSocket”); Regards, Chris
