sudo ppa-purge ppa:sun-java-community-team/sun-java6
Updating packages lists
W: Failed to fetch http://ppa.launchpad.net/sun-java-community-team/sun-java6/ubuntu/dists/natty/main/source/Sources  404  Not Found

W: Failed to fetch http://ppa.launchpad.net/sun-java-community-team/sun-java6/ubuntu/dists/natty/main/binary-amd64/Packages  404  Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.
Warning:  apt-get update failed for some reason
PPA to be removed: sun-java-community-team sun-java6
Warning:  Could not find package list for PPA: sun-java-community-team sun-java6