anchor.diff:    HMaster master = (HMaster) getServletContext().getAttribute(HMaster.MASTER);
     Configuration conf = master.getConfiguration();
     pageContext.setAttribute("pageTitle", "HBase Master Quotas: " + master.getServerName());
  -  boolean exceedThrottleQuotaEnabled = master.getMasterQuotaManager().isExceedThrottleQuotaEnabled();
     List<ThrottleSettings> regionServerThrottles = new ArrayList<>();
     List<ThrottleSettings> namespaceThrottles = new ArrayList<>();
     List<ThrottleSettings> userThrottles = new ArrayList<>();
  -  try (QuotaRetriever scanner = QuotaRetriever.open(conf, null)) {
  -    for (QuotaSettings quota : scanner) {
  -      if (quota instanceof ThrottleSettings) {
  -        ThrottleSettings throttle = (ThrottleSettings) quota;
  -        if (throttle.getUserName() != null) {
  -          userThrottles.add(throttle);
  -        } else if (throttle.getNamespace() != null) {
  -          namespaceThrottles.add(throttle);
  -        } else if (throttle.getRegionServer() != null) {
  -          regionServerThrottles.add(throttle);
  +  MasterQuotaManager quotaManager = master.getMasterQuotaManager();
  +  boolean exceedThrottleQuotaEnabled = false;
  +  if (quotaManager != null) {
  +    exceedThrottleQuotaEnabled = quotaManager.isExceedThrottleQuotaEnabled();
  +    try (QuotaRetriever scanner = QuotaRetriever.open(conf, null)) {
  +      for (QuotaSettings quota : scanner) {
  +        if (quota instanceof ThrottleSettings) {
  +          ThrottleSettings throttle = (ThrottleSettings) quota;
  +          if (throttle.getUserName() != null) {
  +            userThrottles.add(throttle);
  +          } else if (throttle.getNamespace() != null) {
  +            namespaceThrottles.add(throttle);
  +          } else if (throttle.getRegionServer() != null) {
  +            regionServerThrottles.add(throttle);
  +          }
           }
         }
       }
  
positive.code:   <% } %>
  </div>
  
  <jsp:include page="footer.jsp" />
  
negative.code:   </div>
  </div>
  
  <%if (quotaManager != null) {%>
  
  <div class="container-fluid content">
    <div class="row">
      <div class="page-header">
        <h2>Rpc Throttle Enabled</h2>
      </div>
    </div>
    <%if (quotaManager.isRpcThrottleEnabled()) {%>
    <div class="alert alert-success">
      Rpc throttle is enabled.
    </div>
  