code: private static Provider validateProvider(Provider provider) {
          Set<String> ids = provider.getAvailableIDs();
          if (ids == null || ids.size() == 0) {
              throw new IllegalArgumentException("The provider doesn't have any available ids");
          }
          if (!ids.contains("UTC")) {
              throw new IllegalArgumentException("The provider doesn't support UTC");
          }
          if (!UTC.equals(provider.getZone("UTC"))) {
              throw new IllegalArgumentException("Invalid UTC zone provided");
          }
          return provider;
      }
docs: Sets the zone provider factory without performing the security check.
  
  @param provider  provider to use, or null for default
  @return the provider
  @throws IllegalArgumentException if the provider is invalid