XmlProlog () { XmlProlog prolog = myProlog; if (prolog == null) { prolog = (XmlProlog)findElementByTokenType(XmlElementType.XML_PROLOG); if(!MY_PROLOG_UPDATER.compareAndSet(this, null, prolog)) { prolog = MY_PROLOG_UPDATER.getVolatile(this); } } return prolog; }