A JFrame isn't something that could be embedded in an applet, but an applet could open one. Where do those log files reside - on the server where the applet is hosted? If so, are they in a publicly accessible directory? If they are, that would be a security risk, if they're not, then the applet would need to get past whatever access controls you may have in place.
On my planet I'm considered quite beautiful. Thanks to the poetry in this tiny ad:
Devious Experiments for a Truly Passive Greenhouse!