code: public static NameProvider getNameProvider() {
          NameProvider nameProvider = cNameProvider.get();
          if (nameProvider == null) {
              nameProvider = getDefaultNameProvider();
              if (!cNameProvider.compareAndSet(null, nameProvider)) {
                  nameProvider = cNameProvider.get();
              }
          }
          return nameProvider;
      }
docs: Gets the name provider factory.
  <p>
  The name provider is a pluggable instance factory that supplies the
  names of each DateTimeZone.
  
  @return the provider