I read.
Instead of using mRNA, the Johnson & Johnson vaccine uses a disabled adenovirus to deliver the instructions. This adenovirus is in no way related to the coronavirus. It is a completely different virus. Although it can deliver the instructions on how to defeat the coronavirus, it can’t replicate in your body and will not give you a viral infection.
You got this information from a hospital who wants and needs as many people as possible to feel good about getting the shot.
The only way it can "deliver instructions" is if it gives the cells something to read via DNA or RNA.
I would need more information than that to make a decision about putting something into my body that has been declared experimental. You see they don't know for sure what it will do. They are "hoping" that it will provide the results they are seeking. All this is "watching for results." They don't know for sure what kind of reaction any of this will give because it is all experimental.
I am calling it snake oil.