My question is similar to this one, but about store-bought jam.  What is the shelf-life of store-bought jam – i.e. commercially prepared major brands – if not opened?  Are the processes or ingredients for preservation of mass-produced jam superior to at-home sterilization of home-made jam?  Quite simply: I have an unopened jar of jam purchased 18 months ago.  Good to eat now, or not? 
According to the Smucker's web site, their products will last 24 months from the date of production. They should also have a use by date on the label.   According to Shelf Life Advice, it should be good at least one year from the purchase date, although they recognize that it's not exact. I'd say that you could probably try it -- if it's unopened, the sterilization as well as the high sugar content should work in your favor. (It's also better if it's stored in a cool, dark place -- you weren't keeping it on your windowsill, were you?) 