Difference between session timeout descriptors in web.xml and weblogic.xml

Given example below - please elaborate on how you expect the timeout for a web app to behave
given the  configuration below exists in both files (web.xml and weblogic.xml).   Please elaborate -
appreciate the detail.  Thanks.

from web.xml  (30 minutes)
  <session-config>
       <session-timeout>30</session-timeout>
  </session-config>

from weblogic.xml (60 minutes)
<session-param>
   <param-name>TimeoutSecs</param-name>
   <param-value>3600</param-value>
</session-param>Start Free Trial