It's injected using an icing bag, or similar type injector.
A jelly doughnut is made with sweet, risen dough, deep fried, then when cooled, injected with jelly (usually red or purple jelly but it can be any kind) and sometimes sprinkled with sugar. See the...
It depends on how big the jar is. There are many sizes of jelly jars. A lot of jelly jars will say how much actual jelly there is in the jar.
A jelly bean weighs about one gram.
One small jelly bean has about 0.8 grams of sugar