How do I know if JVM Diagnostics (AD4J) Manager is active?

1. To check the Manager status,
Goto Targets->Middleware->JVM Diagnostics->Setup->JVMs&Managers
as given in screen shot

or

2. Goto weblogic server where ad4j manager is deployed
and look at the EMAD4JMANAGER.out file. It should not contain
any errors.