By default, the Web Start sandbox blocks access to the file system through conventional java.io access mechanisms; however, by requiring user interaction for every read and write, the FileOpenService ...

Java Network Launch Protocol (JNLP) files are used to launch applications from a hosted web server on a remote desktop client. Software such as Java Plug-in and Java Web Start programs use JNLP files ...

Isn’t Java Web Start (JWS) supposed to allow web-based distribution of applications? So why would one want to distribute a Java Web Start (JWS) application via CD-ROM? Well, for a number of reasons.