Albert MacSweeny blogs about how to set up a Debian 3.1 (Sarge) guest with Java 1.4, Tomcat 5.0 and Oracle XE installed.
Read the lengthy blog entry
To get started, I downloaded the free version of VMware Server here. You need to go through a brief registration process to obtain a serial number. Once the server was installed and running I got the virtual image for Debian Sarge from here. Unzip the image and open it in the VMware server.