How do I time a method's execution in Java?

Question

1. How do I get a method\'s execution time?
2. Is there a Timer utility class for things like timing how long a task takes, etc?

Mos

Answer 1

Come on guys! Nobody mentioned the Guava way to do that (which is arguably awesome):

import com.google.common.base.Stopwatch;

Stopwatch timer = Stopwatch.createStarted();
//method invocation
LOG.info("Method took: " + timer.stop());

The nice thing is that Stopwatch.toString() does a good job of selecting time units for the measurement. I.e. if the value is small, it'll output 38 ns, if it's long, it'll show 5m 3s

Even nicer:

Stopwatch timer = Stopwatch.createUnstarted();
for (...) {
   timer.start();
   methodToTrackTimeFor();
   timer.stop();
   methodNotToTrackTimeFor();
}
LOG.info("Method took: " + timer);

Note: Google Guava requires Java 1.6+