What are the ways to sign jar (jnlp) files?

Question

Java

Good afternoon!
There is a written utility for uploading data from a bluetooth device to the site.
Launched with java web start (jnlp)
1. What signature options are there for jar and jnlp files so that java doesn't scare the user with a bunch of scary windows from the "everything is bad, we are all going to die" series?
2. Are there any options for signing such an application with certificate authorities like let's encrypt? If not, what are some inexpensive alternatives?
3. It is naive to believe, but still, is it possible to use the site certificate to sign the application?

Answer 1

1. There is only one option - to use a code signing certificate (Code Signing Certificate)
   
2. You can see, for example, here - https://cheapsslsecurity.com/comodo/codesigningcer...
   
3. Certificates use different application policies, so you need to use Code Signing Certificates.