Why don't you google or follow the link I already gave?
Exactly what I thought. You can't name one. Coincidentally, Maven central requires GPG signatures.
As we all know you can only sign a piece of code if it is free of malicious software.
Heck, I read that you can't even make a GPG key without proving your virtue to Richard Stallman in festivus-style competition.
What malicious packages have been found on Maven central?