code: public static boolean isCurrencyAvailable(Locale locale, String... providers) {
          return Objects.nonNull(MONETARY_CURRENCIES_SINGLETON_SPI()) && MONETARY_CURRENCIES_SINGLETON_SPI().isCurrencyAvailable(locale, providers);
      }
docs: Allows to check if a {@link javax.money.CurrencyUnit} instance is
  defined, i.e. accessible from {@link #getCurrency(String, String...)}.
  
  @param locale    the target {@link Locale}, not {@code null}.
  @param providers the (optional) specification of providers to consider.
  @return {@code true} if {@link #getCurrencies(Locale, String...)} would return a
  result containing a currency with the given code.