What is the best way of persisting Web-application related data?

Question

My web-application needs to persist some data (a set of XML documents), i.e. save them so that they can survive server or application shutdowns. Saving those documents as files in server's filesystem does not seem to be convinient to me because the container may run the application directly form WAR and it is impossible (maybe I am wrong?) to modify files inside WAR archive. Forcing WAR extraction requires container reconfiguration and is container implementation dependent, which is not acceptable.
What would be ideal is some individual persistent storage bound to an application which does not require any external enitites (external databases etc). And this storage should not depend on any particular implementation of servlet container.
So is there a way to do something like this?

Answer 1

Saving it to disk seems like your only alternative.
Presuming you have at least some control over the machine where it is deployed to, you could specify a directory to save the xml documents to (ie not one under your web application structure) This would get around the limitations of the WAR file not being extracted.
Make the directory an environment variable/init parameter in your web.xml file.
All you need then is a directory on the server that you have write permissions to.
Ok it requires more setup when deploying the web application, but I thinks its about the only way to accomplish what you want to do.