How can I monitor the thread count of a process on linux?

Question

I would like to monitor the number of threads used by a specific process on Linux. Is there an easy way to get this information without impacting the performance of the proc

Answer 1

JStack is quite inexpensive - one option would be to pipe the output through grep to find active threads and then pipe through wc -l.

More graphically is JConsole, which displays the thread count for a given process.