setEndlessScrollListener crashes when logging is enabled

[wankey]

public FlexibleAdapter setEndlessScrollListener(@Nullable FlexibleAdapter.EndlessScrollListener endlessScrollListener, @NonNull T progressItem) {
    if (DEBUG) {
        Log.i(TAG, "Set endlessScrollListener=" + Utils.getClassName(endlessScrollListener));
    }

    this.mEndlessScrollListener = endlessScrollListener;
    return this.setEndlessProgressItem(progressItem);
}

When endlessScrollListener is null, Utils.getClassName will crash

[davideas]

Thank you @wankey!