Everything. They have absolutely nothing in common.
Karate is a martial art and Judo is used to make bagels.
I don't have a mercedes in my garage!
Try or try not, there is no do.
One shoots but can't hit, the other hoots but can't sh...
Absolutely nothing
A Specialist knows more and more about less and less until he knows absolutely everything about nothing. A Generalist knows less and less about more and more until he knows absolutely nothing about everything.