After editing Your /etc/apt/sources.list file, probably you will get a warning message in the output of the apt-get update command. The warning message will be like this:
W: GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY E9DDA5AAC586799E
You can remove this message in two step:
root@myhost:~# gpg —-keyserver pgpkeys.mit.edu —-recv-key 2E2BCDBCB38A8516
gpg: requesting key B38A8516 from hkp server pgpkeys.mit.edu
gpg: /root/.gnupg/trustdb.gpg: trustdb created
gpg: key B38A8516: public key “Oracle OSS group (Open Source Software group)
” imported gpg: Total number processed: 1
gpg: imported: 1
root@myhost:~# gpg -a —-export 2E2BCDBCB38A8516 | sudo apt-key add –
OK