code: private XPath getXPath() {
          if (xPath == null) {
              XPathFactory factory;
              try {
                  factory = XPathFactory.newInstance(XPathFactory.DEFAULT_OBJECT_MODEL_URI,
                                                     "com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl",
                                                     ClassLoader.getSystemClassLoader());
              } catch (XPathFactoryConfigurationException e) {
                  factory = XPathFactory.newInstance();
              }
              xPath = factory.newXPath();
          }
          return xPath;
      }
docs: /*
  XPath expressions reuse