Is this really new? I remember when System.nanoTime was introduced in the early 2000s largely because of the reasons stated here. System.currentTimeMillis was s

Is this really new? I remember when System.nanoTime was introduced in the early 2000s largely because of the reasons stated here. System.currentTimeMillis was slow and had jitter which made it non-monotonic but it was the best method to call if your timestamp needed to interact with the world outside the JVM. In contrast, if all you cared about was relative times, you'd get a speed and accuracy boost from using System.nanoTime since it actually was monotonic and while a single nanosecond value was pretty meaningless, the difference between two nanosecond values was basically accurate. Benchmarks are a class of problems where the overall time doesn't matter, only the relative time (end - start). The fact that he's using System.currentTimeMillis for his start and end values doesn't give me confidence that he's very knowledgeable about what's to follow.