Your question doesn't have much meaning.
There are multiple directories maintained by the server, non of which I think you want. It also depends on the particular server. For example, some servers store the server's startup directory in a JVM system properties, although you'd never want an application writing to this folder.
Many
java servers run JSP from inside compressed files such as WARs/EARs, so your question amounts to "What is the current running directory for a compressed file?" which again, doesn't have much meaning since you cannot write to it. If you want to read from it from a JSP, use the URL.
The answer to your question is really that you have to specify the directory yourself via some jvm argument or property file, or if possible, use a database.
[ December 22, 2005: Message edited by: Scott Selikoff ]