How to set JVM thread timeout property

The Active Thread count in APM->JVM->Threads increases from 50->60 after I start my performance execution. But does not go back to 50 post test completion.
It seems to me that there must be a timeout property that should be set for threads which will cause JVM to release threads when not in use.

can anybody suggest what needs to be done here to release unused threads post test completion.
and if there is a timeout property existing where do we need to set the property and how.

Hi, @a576821: This seems like a general Java question, rather than one specific to New Relic, so I have moved it to the Conversation Hub. You might also try a more general discussion forum, such as Stack Overflow.