HBASE-29038 Fix NPE in processRS.jsp due to missing MBean value (apache#6556)

Signed-off-by: Duo Zhang <[email protected]>

Author: aaronbee

hbase-server/src/main/resources/hbase-webapps/regionserver/processRS.jsp

@@ -33,6 +33,8 @@
 RuntimeMXBean runtimeBean = ManagementFactory.getRuntimeMXBean();
 ObjectName jvmMetrics = new ObjectName("Hadoop:service=HBase,name=JvmMetrics");
 ObjectName rsMetrics = new ObjectName("Hadoop:service=HBase,name=RegionServer,sub=Server");
+Object pauseWarnThresholdExceeded = JSONMetricUtil.getValueFromMBean(rsMetrics, "pauseWarnThresholdExceeded");
+Object pauseInfoThresholdExceeded = JSONMetricUtil.getValueFromMBean(rsMetrics, "pauseInfoThresholdExceeded");
 
 // There is always two of GC collectors
 List<GarbageCollectorMXBean> gcBeans = JSONMetricUtil.getGcCollectorBeans();
@@ -60,16 +62,16 @@ pageContext.setAttribute("pageTitle", "Process info for PID: " + JSONMetricUtil.
         <th>Started</th>
         <th>Uptime</th>
         <th>PID</th>
-        <th>JvmPauseMonitor Count </th>
+        <th>JvmPauseMonitor Count</th>
         <th>Owner</th>
     </tr>
     <tr>
       <tr>
         <td><%= new Date(runtimeBean.getStartTime()) %></td>
         <td><%= StringUtils.humanTimeDiff(runtimeBean.getUptime()) %></td>
         <td><%= JSONMetricUtil.getProcessPID() %></td>
-        <td><%= (long)JSONMetricUtil.getValueFromMBean(rsMetrics, "pauseWarnThresholdExceeded")
-          + (long)JSONMetricUtil.getValueFromMBean(rsMetrics, "pauseInfoThresholdExceeded") %></td>
+        <td><%= pauseWarnThresholdExceeded != null && pauseInfoThresholdExceeded != null ?
+                (long)pauseWarnThresholdExceeded + (long)pauseInfoThresholdExceeded : 0 %></td>
         <td><%= runtimeBean.getSystemProperties().get("user.name") %></td>
       </tr>
   </table>