Java Web Start: How to write files to windows UNC Path?

I have an Java application for copying开发者_如何学Go large amounts of data from users' workstations to a server. The java.io.File class is supposed to work with UNC paths very well and in fact it does but only when I run the app in standard execution model.

When the application is launched via Web Start I get a FileNotFoundException when trying to open a FileOutputStream with "The network path was not found" in message. Again everything works fine when I download the jar to the PC and lauch it from command line.

My app is signed and i define all-permissions in JNLP.

Edit: I have also discovered that when I map the UNC path to a drive letter it works too.

There is no solution to this. I ended up mounting the path as a named volume and using it trough the volume.