IS it safe to generate paper wallet from this site from an offline PC i am going to store them for years...
by source code you mean zip file on bitaddress.org
download it and open bitaddress.org.html in chrome
I think it is considerably safe that way, make sure you're downloading from the original source
yes that zip file, or even a single standalone bitaddress.org.html file should work just fine
check out the official
[ANN] bitaddress.org Safe JavaScript Bitcoin address/private keythen one day i came to mind what if this site generates address which belong to one HD wallet(as my jaxx can produce infinite amount of public addresses and their respective private keys)
then that's what we called an address collision, it's possible but highly improbable
you can read many threads concerning collision in
Development & Technical Discussion subforum