Uses the ThreadMXBean provided by the JDK to monitor the number of active threads and threads started.
To get information about threads in Spectator, just setup registration of standard MXBeans. Note, if you are building an app at Netflix, then this should happen automatically via the normal platform initialization.
import com.netflix.spectator.jvm.Jmx; Jmx.registerStandardMXBeans(registry);
Gauge reporting the number of active threads.
id: thread category, either
Counter reporting the number of threads started.