Java Web Start can be used to silently download a Java Web Start application
into the Java Deployment Cache:

   javaws -silent -import <jnlp>

Upon failure, no GUI dialog will be shown.
This behavior is geared towards use of Java Web Start in automated environments.
However, there is no way to easily find out, if a download was successful or
failed. In case of failure, only the log file will report it:
e.g.:
#### Java Web Start Error:
#### Unable to load resource: <url>

Appropriate return codes reflecting the reason of failure are needed to programmatically determine what went wrong, in case of failure.