Programs such as servlets modify a virtual server instead of the server as a whole. (To add programs as in iPlanet Web Server 4.1, you can configure only one virtual server.)
Web applications are now supported as described in the Java Servlet 2.2 API specification.
NSAPI has new features. For details, see the Sun Java System Web Server 6.1 SP9 NSAPI Programmer’s Guide.
Some configuration files have changed. For details, see the iPlanet Web Server 6.0 Programmer’s Guide ( http://docs.sun.com/source/816-5687-10/index.html).
The Access Control API has changed. For details, see the comments in the server_root/plugins/include/nsacl/aclapi.h file.