How to give web application/daemons file permissions?

[DKing0]

I have a web application which calls scripts on the linux box it's deployed on. Currently, there are some file permission issues which prevent the scripts from running properly. How can I give my web application the needed permissions? I thought of creating a user 'group' , assigning my web app to that group, and changing the ownership of the script files to the new group. Unfortunately, I'm having trouble with the following:

1. What user id does my web app have?
2. If my web app does not have an user id, how can I create and assign one to it?

Thanks.

[Manko10]

Does your webapp run under Apache? Then it's the Apache user, mostly named www-data. If unsure, let your webapp create file and see which user it belongs to.

[DKing0]

Does your webapp run under Apache? Then it's the Apache user, mostly named www-data.

No; it runs in a Tomcat application server.

If unsure, let your webapp create file and see which user it belongs to.

I've tried that, but oddly the "owner" is root.

[Manko10]

That is not good at all. You should change your configuration to make Tomcat handle requests as an unprivileged user. This user then needs acess und execution rights for the appropriate files.