You can try configuration like this (it's my day to day dev environment):
- create directory 'objectdb' somewhere - in my case ~/objectbd
- put objectdb.jar and objected.conf in this directory
- create ~/objectbd/db (or any other directory where you want store you database - this directory should be defined in objectdb.conf)
- add java agent using export CATALINA_OPTS="-javaagent:~/objectdb/objectdb.jar" or by setting this in your dev software (in my case in eclipse server configuration -> Arguments -> VM arguments)
Of course you can change this on Windows to something like "d:\objectdb" and then use this path. Now you can redeploy you application without deleting database files.