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.

Each JNLP service has a name and a corresponding interface. Two of the most useful services are FileOpenService and FileSaveService, which allow for the reading and writing of files, respectively.

Like Java applets, your application will be constrained to a sandbox on the client unless you used signed jars and configure permissions correctly in your application's JNLP file.

Java Web Start simplifies deployment of applications, but Sun's Plug-in makes the task even easier. See how the Java Plug-in from Sun enables browsers to fetch a Java Virtual Machine (JVM).