What are some practical use cases of annotations that use reflection [duplicate]

I'm in the midst of figuring out why anyone would ever want to use reflectional annotations. However, I have yet to find a good practical code example. What's a good practical use case of reflectional annotations?

EDIT

This is not a duplicate since the questions as marked duplicate to doesn't ask for a practical code example of >reflection<. Neither does any of the answers provide one.