If you’re a Mac user and access web pages with embedded applets, such as the JavaFX samples or documents on the Learn page, you may have noticed a new warning popping up, even for applets you’ve run before:

This new dialog box is appearing because Apple has changed to a
site/URL-based security model in one of its recent Java updates. You
can keep this message from popping up repeatedly by selecting the
checkbox that says Allow all applets from "javafx.com" access.

Source/Kaynak : http://blogs.sun.com/javafx/entry/new_security_warning_for_mac