What's the right place for application configuration information?

Hi there, 

I'm trying to find out what the right place for your own configuration
information is.  I'm talking about the kind of stuff you used to just put
into a .properties file.  I'm new to Struts, and I'm not sure if there's a
better way to do it now.

Does this kind of configuration information belong in:

1) A ServletConfig [seems wrong, since with Struts I don't have my own
servlet].
2) Your own .properties file
3) A separate MessageResource file from the one used for your messages?
or
4) Some other place / method of access I don't yet know about.

I can't seem to find an answer to this in the struts-mailing list archives
or on the web.

Thanks for your help,

-Tim