Makes XPath faster on some JDK imples

gistfile1.txt

private JAXPExtensionsProvider getProviderInstance() throws ClassNotFoundException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
    Class<?> clazz = Class.forName("com.sun.org.apache.xpath.internal.jaxp.JAXPExtensionsProvider");
    Constructor[] constructors = clazz.getDeclaredConstructors();
    for (int i = 0; i < constructors.length; i++) {
        Class[] parameterTypes = constructors[i].getParameterTypes();
        if (parameterTypes.length == 2) {
            return (JAXPExtensionsProvider) constructors[i].newInstance(functionResolver, false);
        } else if (parameterTypes.length == 1) {
            return (JAXPExtensionsProvider) constructors[i].newInstance(functionResolver);
        }
    }
    return null;
}

....

Node doc = node.getNode().getOwnerDocument();
if (doc == null) {
    doc = node.getNode();
}
xpathSupport = (XPathContext) doc.getUserData(XPATH_CONTEXT);

if (xpathSupport == null) {
    JAXPExtensionsProvider jep = getProviderInstance();
    xpathSupport = new XPathContext(jep);
    xpathSupport.setVarStack(new JAXPVariableStack(variableResolver));
    doc.setUserData(XPATH_CONTEXT, xpathSupport, null);
}