I encountered this bug when I installed Eclipse and want to install plug-ins using Eclipse's update function. It always says "Unable to connect to repository". launchpad points out it is a bug related to java and ipv6.
The workaround is to disable ipv6. Try
If this value is 1 you need to disable the setting:
For a persistent fix:
Check /etc/sysctl.conf and /etc/sysctl.d/* for this setting and restart procfs after changing it.