Where/when/how is the io.quarkus.runner.ApplicationImpl generated?

I’m trying to configure an exception to return a http 400: bad request with a custom message in quarkus.
By default a BAD_REQUEST returns without a message, and that is not what I want.

We have a pre-matching request filter and we would like to use Panache to do some basic queries.

I want to create a cookie :

What I found is creating and reading cookie with Spring by using HttpServletResponse. But in my project there is a Quarkus part treating as webservice hosting :