Can you become Diabetic from eating too many fruits or candy?!
Answers: NO you can't
I am sure some people can and have. That is why there are so many with diabetic issues.
I guess your question springs from the fact, that overexposure to f.ex. additives, can make people allergic to them. Overexposure to sugar will not make you diabetic.
One can become a type-2 diabetic from being overweight.
It would take an awful lot of candy, and a ridiculous amount of fruit, to get overweight on that alone.
... I suppose trying to get overweight on f.ex. candy, would probably render you allergic to certain foodcolours :)