Java Web Start is an application distribution technology, allowing developers to easily deploy and update Java desktop applications transparently to the user.
Ant Web Start Task is an Ant task allowing developers to package a desktop application as a WAR (Web Application Archive) to be distributed via Web Start, using the JNLP protocol. The resulting WAR archive can be deployed to a Servlet Container (e.g. Tomcat), and users can then download the application by following a link to the WAR.
The aim of Ant Web Start Task is to make it quicker and easier for developers to deploy their desktop application using Web Start, without requiring detailed knowledge of the intricacies of Java Web Start. For more complex deployment projects however, this may not be suitable.