"I kept getting newspapers sent to me about this great kid named Julius Erving, who was scoring 28, 29 points per game, and I thought to myself, Julius Erving: finally, a great Jewish basketball player." — Billy Crystal
Let's give this statement the attention it deserves. First, we need to explain this "newspapers sent" bit to our younger audience. See, in ancient times, grandmothers (sometimes aunts) would clip interesting articles out of newspapers and send them over mail. (In an envelope. Yes, really.) This was the olden ways of forwarding links... before anyone knew what links were. If you don't believe us, ask your parents.
So, is Billy making a joke here or did he actually think that Julius Erving is a Jewish name? Taken separately, sure, there are a bunch of Jews named Julius and some named Erving (well, usually Irving). But "Julius Erving"? Not exactly "Joshua Edelstein".
Of course, there is also the matter of Julius' nickname... "Doctor". Apparently, he acquired it in all the way back in high school, and, honestly, "Dr. Julius Erving" does sound rather Jewy. But are we to believe that newspapers of the time would including the nickname in its articles?
Billy was probably joking.