The samples at: http://www.oracle.com/technetwork/java/javafx/samples/index.html all use a self signed certificate.

The samples should be signed using a certificate issued by a trusted Certificate Authority so that the publisher of the application is noted as Oracle or JavaFX Sample Team or something significant rather than UNKNOWN.

Ideally, the samples should not be signed at all unless it is strictly necessary - but until they can be made to work without signing, they should at least be signed with a trusted certificate.