Linux/Java - Question about user/owner rights for processes

[Fifthfiend]

OKAY SO

As far as I understand with Linux

A process typically executes with the permissions of the user that executed it.

HOWEVER

It is possible to set a process to execute with the permissions of the user who owns that file.

MY QUESTION IS

If I am running a .jar file with Java, can I set it so that it runs using the permissions of the owner of that .jar file?

OR is it only possible to set it to run using the permissions of the Java executable/command (which I would not do since I think Java is owned by root or some shit).

Or is there some other means by which to determine the permissions with which a particular process runs, independently of the user who initiates that process?