Extending CustomNativeEvent class

FacebookNativeEvent.java

@Override
public void loadNativeAd(@NonNull final Context context,
                         @NonNull final CustomEventNative.CustomEventNativeListener customEventNativeListener,
                         @NonNull final Map<String, Object> localExtras,
                         @NonNull final Map<String, String> serverExtras) {
    final String adUnitId = serverExtras.get(KEY_AD_UNIT_ID);

    if (this.validateAdUnitId(adUnitId)) {
        final FacebookNativeAd nativeAd = this.createNativeAd(context, customEventNativeListener, null, adUnitId);

        this.onLoadNativeAd(nativeAd);

        nativeAd.fetchAd();
    } else {
        customEventNativeListener.onNativeAdFailed(NativeErrorCode.NATIVE_ADAPTER_CONFIGURATION_ERROR);
    }
}