code: private static XMLInputFactory getXMLInputFactory() {
          if (SAFE_INPUT_FACTORY != null) {
              return SAFE_INPUT_FACTORY;
          }
          XMLInputFactory f = NS_AWARE_INPUT_FACTORY_POOL.poll();
          if (f == null) {
              f = createXMLInputFactory(true);
          }
          return f;
      }
docs: Return a cached, namespace-aware, factory.