The tests java/net/MulticastSocket/Test.java and java/net/MulticastSocket/NoLoopbackPackets.java fail on a Linux server with IPv6 enabled for loopback interface but not for another interface. They better check not only for any available IPv6 interface, but ensure that it is not only the loopback interface. The join relys on routing and the loopback interface cannot be used for routing as far as I understand.
--------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Found another multicast issue. - Check for available IPv6 multicast interfaces. Changes: https://git.openjdk.org/jdk/pull/31512/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=31512&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8386595 Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod Patch: https://git.openjdk.org/jdk/pull/31512.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/31512/head:pull/31512 PR: https://git.openjdk.org/jdk/pull/31512
