If you plan on running more than two separate instances of Sun Java System Web Server on your system, an additional 16 MB RAM for each server instance.
Paging space at least as large as the amount of RAM on your system (twice the amount of RAM is recommended).
If you intend to use hostnames during the Sun Java System Web Server installation, DNS properly configured with an entry for your server in a DNS server.
A static IP address on your machine.