AMX exposes a path to the monitoring data associated with a running v3 server. That root of the path is the MonitoringRoot object.

If you have an MBeanServer (or MBeanServerConnection) you can get to it with this snippet:

ProxyFactory.getInstance(mbeanServerConnection).getDomainRootProxy().getMonitoringRoot();

You can read more about ProxyFactory and read more about DomainRoot.

The MonitorRoot allows you to access the ServerMon objects. The method getServerMon() returns a Map, keyed by the name of SOMETHING.

After you get a ServerMon object, you have to use a tool like asadmin list -m