Hi, I'm getting this error when running the tests for xwiki-observation-remote: Caused by: java.lang.RuntimeException: the type of the stack (IPv6) and the user supplied addresses (IPv4) don't match: localhost/127.0.0.1. Use system props java.net.preferIPv4Stack or java.net.preferIPv6Addresses to pick the correct stack at org.jgroups.stack.Configurator.setupProtocolStack(Configurator.java:108) at org.jgroups.stack.Configurator.setupProtocolStack(Configurator.java:54) at org.jgroups.stack.ProtocolStack.setup(ProtocolStack.java:453) at org.jgroups.JChannel.init(JChannel.java:1702) This thread explains the problem: http://old.nabble.com/Protocol-stack-issue-on-dual-stack-(IPv4-and-v6)-mach… This issue has been created to track the problem: https://jira.jboss.org/browse/JGRP-1152 I've tested with jgroups 2.10.0.Beta2 and it works fine. I've seen on http://jira.xwiki.org/jira/browse/XWIKI-4917 that jgroups 2.9 and above require JDK 6+. What do we do? Should we set the jgroups property to force ipv4 or ipv6? Thanks -Vincent