Where do various whiskey flavors come from?

[Hoodwinkd]

From what I have read so far, some flavors come from the fermented grain or fruit, some from the yeast, some from the fermentation and some from the aging medium. It is still not clear to me which flavors come from which source. For example, the whiskey I am sipping now tastes of vanilla, maple and cherries. There is also a touch of sweetness. What causes the sweetness? Is it sugar or some other chemical that makes me perceive sweeteness? I would appreciate it if you could direct me to any articles or posts on the subject. Is there some general guide?

Thanks and Cheers!