Testing the graphhopper by jmeter fail

I want to test the graphhopper with Jmeter.
when i create a http request and pass the source and destination location to graphhopper and simulate 10 users request per second
sometimes i receive this error
java.lang.RuntimeException: To avoid reading partial data we need to obtain the read lock but it failed.

Can you guide me why does this error occur?

Best Regards

You should not start multiple graphhopper instances that try to create the graphhopper cache folder