Instant before = Instant.now();/*do something*/Instant after = Instant.now();Duration duration = Duration.between(start, end);System.out.println("time = " + duration.toMillis() + " ms");Instant before = Instant.now();/*do something*/Instant after = Instant.now();Duration duration = Duration.between(start, end);System.out.println("time = " + duration.toMillis() + " ms");