For logging purposes I want to collect the response times of an external system, and periodically fetch various statistics (such as min/max/stddev) of the response times. I'm looking for a pure in-memory solution.

What Java library can help me with this simple task?

I'm looking for an API that would ideally look something along the lines of:

StatisticsCollector s = new StatisticsCollector();
while (...) {
  double responseTime = ...;
  s.addObservation(responseTime);
}
double stddev = s.getStandardDeviation();
double mean = s.getMean();