There is no check if count is 0 when returning RenderRequestSummaryStatistics.getAverageTime()

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.1.X, 7.2.X, Master
• Fix Version/s: 7.0.10.13 DXP SP13, 7.0.X, 7.1.10 DXP FP17, 7.1.10.4 SP4, 7.1.X, 7.2.10 DXP FP5, 7.2.10.2 DXP SP2, 7.2.X, 7.3.1 CE GA2, 7.3.2 CE GA3, 7.3.10 DXP GA1, Master
• Component/s: Portal Services, Portal Services > Monitoring
• Labels:
  • ee-ts
  • liferay-dxp-70-sp13
  • liferay-dxp-71-sp4
  • liferay-dxp-72-sp2
  • liferay-fixpack-de-90-7010
  • liferay-fixpack-dxp-17-7110
  • liferay-fixpack-dxp-5-7210
• Branch Version/s:
  7.2.x, 7.1.x, 7.0.x
• Backported to Branch:
  Committed
• Fix Priority: 2
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/85278

com.liferay.portal.monitoring.internal.statistics.portlet.RenderRequestSummaryStatistics.getAverageTime() can throw ArithmeticException: Divide by zero, if the portal is monitored before the page is visited. In this case RenderRequestStatisticsSet is a zero-element array, and the execution never gets to the for loop, keeping the count variable zero.

com.liferay.portal.monitoring.internal.statistics.portlet.RenderRequestSummaryStatistics.getAverageTime():

public long getAverageTime() {
 long averageTime = 0;

 long count = 0;

 for (CompanyStatistics companyStatistics :
    _serverStatistics.getCompanyStatisticsSet()) {

 for (RequestStatistics requestStatistics :
     companyStatistics.getRenderRequestStatisticsSet()) {

    averageTime += requestStatistics.getAverageTime();

    count++;
   }
  }

 return averageTime / count;
 }

There should be a validation if the count variable is not zero before dividing.

Reproduction:
1. Copy the Tomcat manager app to the webapps folder
2. Start Tomcat, and during startup, before Liferay deploys hit http://localhost:8080/manager/jmxproxy/?qry=
3. Wait until Tomcat starts up.

You will get

SEVERE [http-nio-8080-exec-3] org.apache.catalina.mbeans.MBeanDumper.dumpBeans Error getting attribute [AverageTime] for object name [com.liferay.portal.monitoring:classification=portlet_statistic,name=RenderRequestPortletManager] 
javax.management.RuntimeMBeanException: java.lang.ArithmeticException: / by zero