The .JNLP file used with this application illustrates how it’s possible for signed code to execute outside the default sandbox environment provided by Java Web Start.

Since JNLP files are simply Java Web Start files that open applications through an Internet browser, any browser that works in Windows 8.1 will open a JNLP file as long as you have Java installed.

Applications launched through Web Start will find that many methods that worked fine directly atop the Java virtual machine will fail with SecurityExceptions inside the Web Start imposed sandbox.