void () { final XmlFile file = createXmlFile("<a/>"); final DomManagerImpl manager = getDomManager(); final DomFileElementImpl<DomElement> fileElement = manager.getFileElement(file, DomElement.class, "a"); final DomElement rootElement = fileElement.getRootElement(); assertNotNull(rootElement); assertTrue(rootElement.exists()); rootElement.undefine(); assertFalse(rootElement.exists()); }