How to get the number of threads in a Java process

Question

How can I see the number of threads in a Java process?

Answer 1

java.lang.Thread.activeCount() 

It will return the number of active threads in the current thread's thread group.

docs: http://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html#activeCount()

Answer 2

ManagementFactory.getThreadMXBean().getThreadCount() doesn't limit itself to thread groups as Thread.activeCount() does.