Ah, one thing that could be useful: when an Application is running under Web start, the following System Environment Variable is defined (and many others):
javawebstart.version using the value of the current JRE used in the client, like for example: javawebstart.version = javaws-1.6.0_15 You can see it enabling the Java Console, and pressing the command to show variables (under Windows is "s"). This could useful to make some tests, like "am I running under Web Start" ? Sandro
