Comment 1 for bug 580181

It certainly looks like the same issue with a new version of java in Lucid:

https://edge.launchpad.net/ubuntu/+source/sun-java6/6.20dlj-1ubuntu3/+build/1704548

But last time this happened because the package was uploaded incorrectly to the partner component of the primary archive, but that is not the case this time:

https://pastebin.canonical.com/32299/

Nonetheless, we do seem to have a corrupt cache again, although I'm not sure in this case where the duplicate record has come from. As outlined on bug 536641, we should: "2. Ensure DistroSeries.updatePackageCache() doesn't create a new cache item for a distro archive if one already exists in another distro archive," to ensure this situation can't happen again.