### Question:
WebXmlUtils { public static void setDisplayName(final String displayName, final Document document, final String comment) { Validate.notBlank(displayName, "display name required"); Validate.notNull(document, "Web XML document required"); Element displayNameElement = XmlUtils.findFirstElement(WEB_APP_XPATH + "display-name", document.getDocumentElement()); if (displayNameElement == null) { displayNameElement = document.createElement("display-name"); insertBetween(displayNameElement, "the-start", "description", document); if (StringUtils.isNotBlank(comment)) { addCommentBefore(displayNameElement, comment, document); } } displayNameElement.setTextContent(displayName); } 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 testSetDisplayName() { WebXmlUtils.setDisplayName("display", webXml, null); final Element displayElement = XmlUtils.findFirstElement("display-name", webXml.getDocumentElement()); assertNotNull(displayElement); assertEquals("display", displayElement.getTextContent()); }