Stopwatch is a class that might not represent an concrete object in a problem application, but is used to measure timing and performance of the application.
public class StopWatch { private final long start; /** * Constructor to initialize the data member of a new stopwatch instance. */ public StopWatch() { reset(); } public void reset() { start = System.currentTimeMillis(); } /** * Return elapsed time (in seconds) since this instance was created. */ public double elapsedTime() { final long now = System.currentTimeMillis(); return (now - start) / 1000.0; } }