"The way to test the performance of System.currentTimeMillis() is straightforward" I'd be worried about that claim. The article executes System.currentTimeMill

"The way to test the performance of System.currentTimeMillis() is straightforward" I'd be worried about that claim. The article executes System.currentTimeMillis in a loop and sums the values. That takes care of dead code elimination, but it will still be subject to other distortionary effects (https://shipilev.net/#benchmarking-1 https://shipilev.net/#benchmarking-1). Maybe the fact that System.currentTimeMillis() is implemented using native code reduces some of the JIT induced benchmarking pitfalls, but I would still prefer to try and use JMH to test. I'm also surprised that performance of System.currentTimeMillis can fall down so far under some circumstances. In one of Cliff Click's talks (maybe https://www.youtube.com/watch?v=-vizTDSz8NU https://www.youtube.com/watch?v=-vizTDSz8NU), he mentions that some JVM benchmarks run it many millions of times a second.