Does/What Does TomCat/Apache Cache?

System

It seems that when one clicks the link to view an XML content file in TeamSite, one sometimes gets a version of the file that has been cached on the server. If one clears the browser cache and request the page again one gets the same data, even if the data in TeamSite has changed. If one restarts TomCat and requests the page again one gets the updated data. I have not noticed this with HTML data, only with XML data. The problem is that to get a fresh view of XML data that has been updated or a transform using an updated XSLT one has to restart TomCat which is not only a pain but brings down the system for everyone and takes longer than it should.

I first noticed this with the VFE configuration files but they don't change as often so it's not as bad - when the browser requests them, they don't always get the updated version.

Is there any way to configure Apache and Tomcat to not cache anything? or a command to clear the content cache without restarting the server?

IE6, W2KSP2, TS5.5.2SP2a