code: public static void setFallbackLocale (@Nonnull final Locale aFallbackLocale)
    {
      ValueEnforcer.notNull (aFallbackLocale, "FallbackLocale");
      s_aRWLock.writeLocked ( () -> s_aFallbackLocale = aFallbackLocale);
    }
docs: Set the fallback locale in case none could be determined.
  
  @param aFallbackLocale
  Locale to use. May not be <code>null</code>.
  @since 7.0.4