NO PACOTE J2SDK 1.4.2, NO INSTALAR UM ATALHO CHAMADO JAVA WEB START…O QUE É ESSE ATALHO…PRA QUE SERVE…
É como se fosse uma demonstração de java, o que ele pode fazer, no estilo PLUGIN! Valeu?
Não é bem isso…veja:
[quote]Java Web Start software provides a flexible and robust deployment solution for Java technology-based applications based on the Java Community Process program (JCP). For example, an application might depend APIs in Sun’s Java Runtime Environment 1.4.0 (or later). When a user first accesses this application, the Java Web Start software will download all the needed files for the application, as well as download the Java Runtime Environment (JRE) if the requested version is not available locally. The ability to automatically download a JRE is one of the key features to ensure robust deployments. It ensures that the JRE that your application is tested on will be available on the user’s machine, as well as make it possible to seamlessly upgrade to improved versions of the Java 2 platform over time.
The java.sun.com auto-download feature simplifies Java Web Start deployments because it makes commonly used software readily available for use with Java Web Start. Typically, only an extra line has to be added to a JNLP file to take advantage of this feature. In contrast, without the auto-download feature, developers would be forced to repackage and host the software themselves - adding a significant overhead to the deployment burden. As an added benefit to both developers and end-users, this minimizes the download time for an application since each JRE will be shared between multiple applications.[/quote]
É uma solução de deployment, estilo auto-download…
Valeus… 
ele tambem serve pro applet