The main fruit that is a symbol of long life and good luck in China is the Grape.
However besides grapes their are also a few other fruits that also symbolizes long life and good luck in China and those are the Plums and the Jujube which is a type of date.
The grapes, Jujube and Plums are associated with wealth, fortune, gold, prosperity and fertility and good luck.
So by eating those fruits you're supposed to have wealth, fortune, prosperity and fertility.
I wish it were true that if I ate some grapes that I would amass a lot of wealth and could quit my job and never have to go to work again.
I eat grapes all the time and although I'm healthy as a result it has never brought me any wealth other than a wealth of good health.