Application Server: Session Sharing
From Resin 4.0 Wiki
Session Sharing Between Domains
Sessions are tied to the JSESSIONID cookie.
By default, the JSESSIONID cookie uses the full host name for the cookie domain. So requests to www.foo.com will not share cookies (and thus sessions) with secure.foo.com.
cookie-domain
If all your host names end with "foo.com", then simply set "domain-cookie" to share cookies between domains:
<session-config> <cookie-domain>foo.com</cookie-domain> ... </session-config>
cookie-domain-regexp
If you have more than one domain using the same web application, or need more control, you can use the cookie-domain-regexp parameter.
cookie-domain-regexp accepts a regular expression used to extract the domain from the requested host. Probable configuration:
<session-config> <cookie-domain-regexp>[^.]*\.[^.]*$</cookie-domain-regexp> ... </session-config>
For example, using this regexp will produce the following:
Host: xxx.yyy.zzz.foo.com = Set-Cookie domain: foo.com Host: zzz.foo.com = Set-Cookie domain: foo.com Host: foo.com = Set-Cookie domain: foo.com Host: bar.com = Set-Cookie domain: bar.com