I have a JNLP file that will launch my application. It is working fine and listing the java cache viewer also. In my application in server side added new JAR file. And push to client by a JNLP with <component desc> attribute, at this time when customer launches the application it is not listed in the Java Cache viewer.
I guess you simply have multiple Java Runtimes on your machine.
So the Java Webstart that starts the application is different from the one that runs your Webstart Cache Viewer ....
However of course that would need further verification ... but it should be quite easy to find out.
You can simply download the JNLP and start with javaws YOURFILE
if then javaws -viewer STILL shows ZERO then its really strange, I am not aware of any mechanism/option to prevent caching resources in a Java Webstart.