### Question:
WebXmlUtils { public static void addWelcomeFile(final String path, final Document document, final String comment) { Validate.notNull(document, "Web XML document required"); Validate.notBlank("Path required"); Element welcomeFileElement = XmlUtils.findFirstElement(WEB_APP_XPATH + "welcome-file-list", document.getDocumentElement()); if (welcomeFileElement == null) { welcomeFileElement = document.createElement("welcome-file-list"); insertBetween(welcomeFileElement, "session-config[last()]", "error-page", document); if (StringUtils.isNotBlank(comment)) { addCommentBefore(welcomeFileElement, comment, document); } } appendChildIfNotPresent(welcomeFileElement, new XmlElementBuilder("welcome-file", document) .setText(path).build()); } private  WebXmlUtils(); static void addContextParam(final WebXmlParam contextParam, final Document document,
      final String comment); static void addErrorCode(final Integer errorCode, final String location,
      final Document document, final String comment); static void addExceptionType(final String exceptionType, final String location,
      final Document document, final String comment); static void addFilter(final String filterName, final String filterClass,
      final String urlPattern, final Document document, final String comment,
      final WebXmlParam... initParams); static void addFilterAtPosition(final FilterPosition filterPosition,
      final String afterFilterName, final String beforeFilterName, final String filterName,
      final String filterClass, final String urlPattern, final Document document,
      final String comment, List<WebXmlParam> initParams, final List<Dispatcher> dispatchers); static void addFilterAtPosition(final FilterPosition filterPosition,
      final String afterFilterName, final String beforeFilterName, final String filterName,
      final String filterClass, final String urlPattern, final Document document,
      final String comment, final WebXmlParam... initParams); static void addListener(final String className, final Document document,
      final String comment); static void addSecurityConstraint(final String displayName,
      final List<WebResourceCollection> webResourceCollections, final List<String> roleNames,
      final String transportGuarantee, final Document document, final String comment); static void addServlet(final String servletName, final String className,
      final String urlPattern, final Integer loadOnStartup, final Document document,
      final String comment, final WebXmlParam... initParams); static void addWelcomeFile(final String path, final Document document, final String comment); static void setDescription(final String description, final Document document,
      final String comment); static void setDisplayName(final String displayName, final Document document,
      final String comment); static void setSessionTimeout(final int timeout, final Document document,
      final String comment);  }### Answer:
@Test public void testAddWelcomeFile() { WebXmlUtils.addWelcomeFile("/welcome", webXml, null); final Element welcomeFileElement = XmlUtils.findFirstElement("welcome-file-list/welcome-file", webXml.getDocumentElement()); assertNotNull(welcomeFileElement); assertEquals("/welcome", welcomeFileElement.getTextContent()); }