There is an error in the setDaneProvider method; it sets the local daneProvider instead of the global defined DNSUtil.daneProvider.
/**
* Set the DANE provider that should be used when DANE is enabled.
*
* @param daneProvider
*/
public static void setDaneProvider(SmackDaneProvider daneProvider) {
daneProvider = Objects.requireNonNull(daneProvider);
}