Some MBeans exposed by various supported application servers are preconfigued as JMX Metrics that can be viewed in the JMX Metrics Browser.
In this screen capture of the JMX Metrics Browser, under Web Container Runtime, you can see the two metrics "Error Count" and "Request Count".
Where did these come from? These metrics were configured from MBeans exposed by the Tomcat web container. To see the configuration for these metrics, do the following:
1. Select Configure -> Instrumentation.
2. Select the application.
3. Select the JMX tab.
In this "metric rule" named Tomcat_GlobalRequestProcessor", you can see where the Metric Path and the MBean matching criteria in the domain "Catalina" have been specified. This path in the metric browser was seen in the first screen capture.
The next screen capture shows the two attributes of this MBean.