Apache Commons is generally known as a solid project. Keep in mind, though, you’ll still have to send a verification email to the address if you want to ensure it’s a real email, and that the owner wants it used on your site.
EDIT: There was a bug where it was too restrictive on domain, causing it to not accept valid emails from new TLDs.
This bug was resolved on 03/Jan/15 02:48 in commons-validator version 1.4.1
