System nanotime vs system currenttimemillis. nanoTime() and we disregard the variance i...

System nanotime vs system currenttimemillis. nanoTime() and we disregard the variance in cost of commands, it appears as if there would be not a linear graph on the same resolution. nanoTime() that are a substantial fraction of a second apart is bound to be a large number. (Windows 2003 The Java System nanoTime () method returns the current value of the most precise available system timer, in nanoseconds. nanoTime ()的1000000倍 System. nanoTime() を呼び出して 3761546426118 という値が返ってきて Aug 18, 2024 · System. currentTimeMillis () vs System. What does "getting affected by systems real-time clock " mean ? Discover the key differences between System. nanoTime() is less about precision but more about accuracy. currentTimeMillis() is based on wall clock time and System. java, but start N threads, where N is between 1 and 24 (the total number of cores in our dual-processor system, including hyper-threading ones). nanoTime ()的初始值是在 本JVM实例 启动时"随机"选择的一个数字,随着JVM的运行而递增（常用来计算实时时间差）,System. There are 2 main differences between them. nanoTime () 's disadvantage is it doesn't have a fixed reference point Mar 26, 2025 · The code is basically the same as before. Mais lequel doit être utilisé dans quelle condition ? Et lequel est le plus efficace ? À première vue, il peut sembler que nanoTime () devrait être utilisé car il donne une valeur de temps plus précise (en nanosecondes, par rapport aux millisecondes renvoyées par l’autre Feb 2, 2024 · The System. Dec 8, 2008 · 精度与Precision我想知道的是，当我在游戏中更新对象的位置时，我应该使用System. currentTimeMillis()还是System. nanoTime and System. info("Short task duration: " + duration + " nanoseconds"); assertTrue(duration >= 0); } Copy In this еxamplе, thе test mеthod usеs nanoTimе () to capturе thе start and еnd timеs of a short task, providing high prеcision in nanosеconds. The wall clock can be set by the user or the phone network (see setCurrentTimeMillis(long)), so the time may jump backwards or forwards unpredictably. nanoTime () and System. CurrentTimeMillis returns the current time in milliseconds from the Epoch In Java, when you want to measure elapsed time with minimal overhead, you generally have two options: System. currentTimeMillis() or comments on this will be most appreciated. When tracking performance in production, we need millisecond resolution. currentTimeMillis () method returns the current time in milliseconds. currentTimeMillis () provide time-related functionality but serve different purposes and are based on different underlying mechanisms. System. getNanoTimeAdjustment(offset) use the same time source - System. 根据报告的信息，读取全局变量自然非常快-大约6个周期。 System. currentTimeMillis() depends on the implementation and on the Operating system and is usually around 10 ms. currentTimeMillis() and some use System. nanoTime () 主要被称为昂贵调用，用于获取更具体的时间值。而且，System. nanoTime vs currentTimeMillis and Alternatives” When dealing with performance metrics and execution profiling in Java, selecting the appropriate method for measuring elapsed time is paramount for obtaining accurate results. SystemClock. nanoTime()。尽管两者都能用来衡量时间，但它们服务于不同的目的，具有各自的特性。 在这个教程中，我们将探讨这两种方法之间的差异，并理解何时选择使用每一种。 The currentTimeMillis and nanoTime methods are useful for measuring time intervals during execution of an application. currentTimeInMillis() . Jan 16, 2021 · What clock does System. While System. nanoTime() gives you access to a high-resolution time source (nanoseconds) that is designed for measuring elapsed time and it is not related to the system clock or any “wall-clock”, see the javadoc of System. nanoTime() which returns the current value of the most precise available system timer, in nanoseconds. There are several differences between these two calls, let’s break them down. You can compare such values obtained in different JVMs even on different machines and this is as good as synchronization of clocks on these machines. Learn the key differences between System. nanoTime ()的精确度更高一些，如今的硬件设备性能越来越好，如果要更精密计算执行某行代码或者某块代码所消耗的时间，该方法会测量得更精确。 2. currentTimeMillis() returns the time in milliseconds since midnight, January 1, 1970 UTC. 10 -9 seconds, as described in the javadoc. Understanding the differences between these methods is crucial for selecting the appropriate one for your needs. currentTimeMillis()는 현재 시간을 밀리초 단위로 반환한다. nanotime is both of these things, Stopwatch just wraps this so you don't have to think about it as much. nanoTime 的定义 翻译一下就是： 补充说明 对于使用t1-t0< Jul 13, 2020 · The performance of an app has no influence over what happens in deep sleep, so our best options are SystemClock. Changing system time will affect System. nanoTime() returns a time value whose granularity is a nanosecond; i. toEpochMilli () and System. This is the basis for most interval timing such as Thread. nanoTime ()没有什么意义，因为该值是随机的，无法表示当前的时间。 Nov 12, 2025 · System. Jul 1, 2022 · Java有两个取时间戳的方法：System. currentTimeMillis () 是最常用的两种。本文将深入探讨这两个API的特点、应用 System. nanoTime() does NOT change with the wall clock. Is this per core or for the entire system? Let’s run a similar test to Time. 5M operations/second). Depending on your JVM, there may be other mechanisms available, but these are generally the two standard ways to time things in Java. nanoTime ()和System. ) Jan 2, 2014 · System. Note that you can only use this to calculate elapsed time, you cannot use its value as an absolute time. System API currentTimeMillis() Returns the current time in milliseconds nanoTime() Returns the current value of the running Java Virtual Machine's high resolution t Dec 20, 2019 · Java offers two basic primitives for measuring time: System. Jul 4, 2022 · testing. nanoTime for elapsed time in nanoseconds Instant. currentTimeMillis() returns so called “time-of-day clock” time or wall-clock time, so it’s good for time-stamping. println("//// Test System. nanoTime () and when to use each. nanoTime() 明显非常慢。 具体输出内容我就不放出来了，因为不具有参考价值，大多数生产环境用的是 Linux。 近期热文推荐： Dec 15, 2008 · System. This is in contrast to System. currentTimeMillis() returns the number of milliseconds since the start of the Unix epoch – January 1, 1970 UTC. currentTimeMillis (), which is optimized for retrieving the current wall-clock time. currentTimeMillis ()提供真实世界时间，但存在性能陷阱和NTP同步问题；System. Choose nanoTime) for precise elapsed time measurements in performance-critical code, though it requires 100+ cycles. nanoTime() is that System. currentTimeMillis提供毫秒级精度，适合日常时间记录需求；System. nanoTime() is a valuable tool provided by the Java standard library that allows developers to measure time with high precision. nanotime in the same way as System. Jul 17, 2021 · 本文详细解析了Java中System. currentTimeMillis() returns the current time in milliseconds since the Unix epoch (January 1, 1970, 00:00:00 GMT Feb 15, 2013 · I know that System. currentTimeMillis(), which returns the current time in milliseconds since the Unix epoch, System. uptimeMillis() and System. Therefore, if the elapsed time is measured in a different time unit we must convert it accordingly. On this page, we look at the differences between System. Mar 24, 2021 · It appears to be that when you ask System. To measure a time interval in milliseconds, invoke currentTimeMillis twice, at the beginning and end of the interval, and subtract the first value returned from the second. nanoTime () et System. lang. nanoTime ()无法表示当前时间,本质上它是一个随机数字. nanoTime: Precision and Accuracy in Time Measurement When dealing with precise timekeeping in Java, the two dominant methods are System. 시간은 계속 흘러가기 때문에 시간을 고유한 값으로 사용하는 경우가 많다. currentTimeMillis() & System. nanoTime ()在JDK7和JDK8下输出的值怎么完全不一样 System. nanoTime()？他们的移动变化与自上次调用以来所经过的时间成正比，我希望尽可能精确。我读到过，不同操作系统之间存在一些严重的时间分辨率问题(即Mac / Linux的分辨率几乎为1ms，而Windows的 Jun 18, 2012 · Java timing, System. It is not accurate and it drifts. nanoTime提供纳秒级精度，适用于高精度计时，但不适用于获取当前时间。 In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. currentTimeMillis ()与System. Use the appropriate method based on your specific timing requirements and precision needs. currentTimeMillis() 和 System. nanoTime (). nanoTime() 是使用QueryPerformanceCounter / QueryPerformanceFrequency API实现的（如果可用，则返回 currentTimeMillis*10^6)。 QueryPerformanceCounter (QPC) 在运行它的硬件上以不同的方式实现。 Apr 22, 2020 · JVM源码分析之System. nanoTime()，它们的使用场景是有区别的，当前网上一些文章对于这两个方法的性能讨论存在一 One quite interesting feature of the difference between System. nanoTime () 和System. nanoTime(); long duration = endNanoTime - startNanoTime; logger. Is system nanoTime () reliable? May 1, 2024 · There are two similar methods in Java: System. 즉, 1퍼센트 이내의 측정 정확성을 유지하려면, 매 100마이크로초 이내에 한 번 이상 이 API가 호출되면 곤란하다. nanoTime() is more precise than uptimeMillis(), but that's only useful for micro-benchmarks. currentTimeMillis () le dará el tiempo transcurrido más preciso posible en milisegundos desde la época, pero System. now (). wait(millis), and System. And, System. 7 I want to add that System. now for the current time on the clock, captured in microseconds in Java 9+ (milliseconds in Java 8), with nanoseconds resolution. This clock stops when the system enters deep sleep (CPU off, display dark, device waiting for external input), but is not affected by clock scaling, idle, or other power saving mechanisms. ----- So you plotted currentTime() - baseTime vs nanoTime() - baseNanos. nanoTime ()) a function with a guaranteed accuracy on Windows? More specifically, if I run a comparison between a previously-stored time and the current time using those functions, is there any guarantee that those functions will remain accurate? Apr 28, 2019 · JDK提供了两个方法，System. Jul 29, 2025 · “Java Time Measurement: System. May 7, 2025 · System. currentTimeMillis() will change accordingly. currentTimeMillis ()是什么 System. nanoTime与System. nanoTime이 마이크로초 이내에 실행되는 OS 함수 호출을 포함한다. 1. currentTimeMillis()和System. Stability of the Point of Origin System. nanoTime() provides a more accurate way to measure elapsed time between two points in a program. currentTimeMillis(): Designed to report the wall-clock time (the time displayed on a device). . For example, many operating systems measure time in units of tens of milliseconds. if you change the date, hit a leap second, etc. currentTimeMillis() for accurate elapsed time measurements, including potential pitfalls and best practices. 在同一机器上的不 Java有两个取时间戳的方法： System. nanoTime () batter than System. This can lead to noticeable discrepancies between their outputs under certain circumstances. currentTimeMillis Sep 5, 2015 · Bit late to the party, but I'd say nanoTime is unreliable for long intervals, since nanoTime() and currentTime (either System. In a comment in the millis() method, it says (quoting Java 15): System. In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. nanoTime (): Why NanoTime is Preferred & What 'Affected by System Real-Time Clock' Means In Java, measuring time is a common task—whether you’re benchmarking code, profiling application performance, scheduling tasks, or tracking elapsed time. currentTimeMillis比较 首先： currentTimeMillis返回的是系统当前时间和1970-01-01之前间隔时间的毫秒数，如果系统时间固定则方法返回值也是一定的（这么说是为了强调和nanoTime的区别），精确度是毫秒级别的 nanoTime的返回值本身则没有什么意义，因为它基于的时间点是随机的，甚至可能 Mar 20, 2012 · 이러한 영향의 정도는 플랫폼에 따라 다르다. Unlike System. currentTimeMillis定义 翻译一下就是： 补充说明 2、System. nanoTime()，这两个方法都可以用来获取表征当前时间的数值。但是如果不仔细辨别这两个方法的差别和联系，在使用当中也很容易栽跟头。笔者在前不久的工作当中使用System. now()) use fundamentally different clocks. nanoTime () measure "wall clock" time, at least in the sense that the difference between 2 measurements is how much time has passed on A clock. nanoTime ()的初始值是在 本JVM实例 启动时"随机"选择的一个数字,随着JVM的运行而变化,System. nanoTime(): Designed specifically for measuring elapsed time intervals. currentTimeMillis ()为何不是System. Nov 4, 2025 · System. In this tutorial, we will learn two most commonly used Java System functions - System. The first obvious reason is nanoTime () gives more precise timing and the other reason I read that the latter is affected by adjustments to the system’s real-time clock. sleep(millls), Object. nanoTime() repeatedly you would be able to get a linear graph with nanosecond resolution. Understanding the performance implications of each can help you decide which to use based on your precision requirements. nanoTime(). Oct 27, 2020 · System. systemUTC(), you will find that it uses an internal SystemClock class. currentTimeMillis及nanoTime原理详解 提取关键问题： 在mac下发现System. But is it always efficient on the Feb 2, 2024 · long endNanoTime = System. currentTimeMillis() for elapsed time — it’s a legacy wall-clock API affected by clock adjustments. nanoTime ()提供了更高的精度和稳定性,特别适合测量短时间间隔和需要高精度的场景。 而System. currentTimeMillis() will give you the most accurate possible elapsed time in milliseconds since the epoch, but System. Jul 23, 2017 · Multi-threaded performance The currentTimeMillis() based on HPET runs for 640 ns (1. Dec 29, 2024 · System. currentTimeMillis表示系统时间,这就导致了的它们的几个差别: System. currentTimeMillis两个Java方法的特点及适用场景。System. currentTimeMillis() is based on the system clock, which is, most of the time, based on a quartz clock inside a computer. currentTimeMillis (). Is System. Java fournit deux méthodes pour chronométrer les opérations, System. nanoTime ()方法在Java环境中可以帮助找到两个指针之间的差异。 简单来说，它可以在进程开始前获取一个时间读数，然后在执行方法后获取另一个时间读数。 💡 Exploring Java's System. nanoTime () for accurate game timing? Learn the key differences and best practices for precision. The latter is monotonic, whereas the first may make arbitrary backward or forward jumps as the user or NTP daemon changes the system clock, or leap seconds are inserted. long duration = endTime - startTime; // Calculate the duration of the loop execution in nanoseconds. System. The difference between two calls to System. 예를 들어, 최근 윈도 시스템에서는 System. currentTimeMillis() and System. elapsedRealtimeNanos() - Counts elapsed time even on deep sleep, but requires API level 17. Nov 19, 2016 · According to java. Which one sh Jul 29, 2025 · “Java Time Measurement: System. nanoTime() uses the Unix epoch as a reference thus it can go back in time! Sep 1, 2021 · 1、System. nanoTime is the raw system clock, using the finest resolution available. nanoTime() uptimeMillis() vs nanoTime() System. nanoTime () 之间的时间段如何转换成ms 在Java中使用System. nanoTime () serve different timing purposes in Java. Both are time related functions, i. nanoTime() returns the elapsed running time of the JVM in nanos, whereas System. Call System. Accuracy Precision refers to the smallest unit of time that can be measured, while accuracy refers to how close the measurement is to the actual time. nanoTime ()的区别及应用场景。前者适用于获取当前时间，返回从1970年1月1日午夜到现在的毫秒数，但不建议用于计时；后者提供了一个不受NTP影响的稳定递增的纳秒数，适用于需要高精度计时的场景。 Dec 11, 2024 · Dive into the nitty-gritty of Java's time handling! We'll break down the differences between Instant. Jan 10, 2016 · Here is my modest proposal: When the JVM starts Call System. Instead use the System. currentTimeMillis() simply limits the resolution to milliseconds. I just rearranged that equation and tried making a clock such that currentTime() = baseTime + nanoTime() - baseNanos Answer In Java, both System. Nov 24, 2025 · Java时间获取机制解析：currentTimeMillis ()与nanoTime ()的深度对比 摘要：本文深入剖析Java中两种时间获取方式的本质区别。 System. Apr 12, 2018 · Java provides two methods to time operations, System. accept(nanoTest); System. This clock is guaranteed to be monotonic, and is suitable for interval timing when the interval does not span device sleep. Mar 25, 2013 · 12 In a nutshell, whenever you change system time, the value returned by System. currentTimeMillis() or Instant. 두 가지 방법은 상당한 차이가 있다. nanoTime () 领先一步，其准确性 System. currentTimeMillis() - Good, but not appropriate because it can be changed by the user or by code with setCurrentTimeMillis(long). nanoTime () mainly known as an expensive call, is used to get a more specific value of time. currentTimeMillis是 System. currentTimeMillis ()则更适合处理实际日期时间和长时间间隔的计算。 Both System. currentTimeMillis () is NOT A TIMER, it is the "wall clock". The only difference is the method used to get timestamps – nanoTime () instead of currentTimeMillis (). nanoTime () in Java for precise time measurements. currentTimeMillis vs. accept(millisTest); } } 因为我用的是 Windows，所以执行输出当中 System. nanoTime() - Works great if Android is running, but stops on deep sleep (this is bad). In a game loop everyone uses System. In contrast, `nanoTime ()` is designed for precision and stability, making it the preferred choice for most timing tasks. Fortunately The advantage is high accuracy currentTimeMillis is based on the system time, which means that if you change the system time during the execution of the program, the result will be wrong, and nanoTime is based on the time slice of the CPU to calculate the time and cannot be artificially interfered. currentTimeMillis() and store as starting "wall clock" time: long currentTimeMillis0. nanoTime () returns nanoseconds, indicating that System. currentTimeMillis () but does it persist over sleep? Asked 12 years, 2 months ago Modified 12 years, 2 months ago Viewed 5k times This is the basis for most interval timing such as Thread. The first is that they are at different levels of precision. nanoTime() は、 不連続な時間の変化の影響を受けません。 上記の場合、処理の途中で時刻が変更されても、 total が実際の処理時間を表す値になります。 一方で、あるタイミングの現在時刻を取得するのには不向きです。 例えば、 System. So you can do this: Nov 1, 2014 · System. currentTimeMillis() is the standard "wall" clock (time and date) expressing milliseconds since the epoch. Oct 7, 2019 · 总结一下： 1. currentTimeMillis() can jump back or forward by 1-2 seconds each time as NTP corrects that drift, making accurate time stamps meaningless. currentTimeMillis is the system time "cleaned up" a bit to have a consistent base. nanoTime两个时间API的区别，详细解释了它们的精度、应用场景及各自的优缺点，帮助开发者在不同的需求场景下选择合适的时间测量方法。 Oct 30, 2022 · System. Understanding these Jan 9, 2026 · A critical distinction is that `currentTimeMillis ()` is "affected by the system real-time clock," which can lead to unexpected results when measuring elapsed time. The unit of time of the return value is a millisecond, the granularity of the value depends on the underlying operating system and may be larger. nanoTime () is more precise. There are two standard ways to time operations in Java: System. Example: Aug 5, 2025 · 结论 System. Dec 26, 2022 · Java offers two basic methods for measuring time value: currentTimeMillis and nanoTime. Jan 9, 2026 · System. nanoTime ()的值很奇怪，究竟是怎么算出来的 System. currentTimeMillis () have different levels of precision but only have basic "api" support (math operations on long), but are faster to get and smaller to keep in memory. currentTimeMillis与System. The first three use cases mentioned in the article are ones for which you should NEVER use currentTimeMillis (), but nanoTime () in stead. What functions provide the best fidelity, and what pitfalls exist in common approaches? Jan 5, 2017 · nanoTime (), as the java doc says, is a precision timer. 单独获取System. nanoTime () will always produce positive elapsed time, currentTimeMillis will not (e. 概述 Java中常用的两个时间测量方法是 System. 1w次，点赞8次，收藏7次。本文详细比较了System. You’ll want to use currentTimeMillis) for wall-clock time and general event logging, as it’s more efficient at 5-6 CPU cycles but offers millisecond precision. nanoTime(): A Dive into Time Measurement 💻⏰Ever wondered about the nuances between System. currentTimeMillis() The method System. Apr 30, 2011 · Since System. nanoTime() and System. currentTimeMillis () returns milliseconds, while System. out. The value returned represents nanoseconds since some fixed but arbitrary time (in the future, so values may be negative) and provides nanosecond precision, but not necessarily nanosecond accuracy. This article explores the nuances between these methods, addressing their accuracy, precision, and suitability for specific applications. Oct 15, 2024 · System. nanoTime ()和currentTimeMillis ()的使用和区别，包括它们的实现机制、性能差异以及在不同操作系统上的行为。 nanoTime提供了更高的时间精度，适合测量短时间内发生的事件，而currentTimeMillis则与日期和时间相关，适合记录时间跨度。 The granularity of System. nanoTime () is designed for high-resolution timing, it incurs more overhead compared to the simpler System. nanoTime() is based on a system timer that is independent (*) of wall clock time, I thought I could use changes in the difference between these values to detect system time changes. May 30, 2024 · When measuring elapsed time in Java, two common methods are utilized: System. It is immune to system clock modifications, such as manual adjustments or automatic corrections like daylight saving time transitions or leap seconds. But which one should be used in which condition? And which is more efficient? From the first look it might seem that nanoTime () should be used because it gives more precise value of time (in nano seconds, compared to milli seconds that the other method returns). g. Jan 17, 2024 · Majority cases elapsed time calculated with nanoTime is higher than elapsed time computed with currentTimeMillis and it's observed from -2 milliseconds to +150 milli seconds. May 6, 2016 · System. I run code on a Windows virtual machine that has heavy time drift. currentTimeMillis() vs System. Let’s also note that nanoTime (), obviously, returns time in nanoseconds. currentTimeMillis () most authentic possible passed time, helps to get the time value based on the operating system. nanoTime()，它们的使用场景是有区别的，当前网上一些文章对于这两个方法的性能讨论存在一些片面的描述，本文希望能给出一个简单的最终答案。Sy… Oct 27, 2025 · 文章浏览阅读1. nanoTime () le dará un tiempo preciso de nanosegundos, en relación con algún punto arbitrario. nanoTime()은 현재 시간을 나노초 단위로 반환한다. currentTimeMillis (), and help you pick the right one for your needs. 在同一机器上的不同JVM上,System. Dec 4, 2019 · Gettimeofday() is the same Posix call the System. This results in a non-consistent nanoTime over each run. currentTimeMillis () (or, for that matter, System. currentTimeMillis () and System. Oct 12, 2017 · This means System. currentTimeMillis is not monotonic and isn't good precision, so gives you unfair benchmarks. currentTimeMillis() right after System. 👉 Avoid System. currentTimeMillis in Java for accurate time measurements in your applications. nanoTime() is now the preferred method for measuring time over System. nanoTime () in Java, including usage and best practices. What functions provide the best fidelity, and what pitfalls exist in common approaches? Feb 2, 2024 · 1. nanoTime (), however, returning nanoseconds, may arguably be better suited to measure deltas (although reportedly a nanoTime () call can be slower than a currentTimeMillis () call - my experiments contradict this: they seem to take exactly the same amount of time). Nov 4, 2025 · Explore the differences between Java's System. Most methods that accept a timestamp value currently expect the uptimeMillis() clock. Jul 30, 2021 · 本文深入探讨了Java中的System. currentTimeMillis ()表示系统时间 (即UTC). currentTimeMillis( In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. currentTimeMillis () 是最真实的可能传递时间，有助于根据操作系统获取时间值。第一个函数以纳秒为单位返回时间值 (有时会给出负值)，而第二个函数以毫秒为单位返回时间值。因此很明显，System. When the first look only difference between methods can be seen as metrics We would like to show you a description here but the site won’t allow us. It is essentially whatever the OS provides. nanoTime() and store as starting "nano" When I am updating my object's position in my game, should I use System. e. 이런 경우 Dec 24, 2024 · Precision vs. currentTimeMillis() and VM. currentTi Oct 25, 2024 · 引言 在现代软件开发中，时间管理是一个至关重要的环节。无论是性能优化、日志记录，还是定时任务，都需要精确的时间测量和控制。Java作为一门广泛应用的开发语言，提供了多种时间管理的API，其中System. currentTimeMillis()"); testing. So Dec 20, 2021 · In the next lines, I will examine two of them that exist in System class, “currentTimeMillis” and “nanoTime”. 文章浏览阅读986次。本文深入对比分析了Java中System. May 31, 2024 · Java는 시간 값을 측정하는 두 가지 기본 메소드를 제공한다. Dec 9, 2008 · System. nanoTime() that relate to time measurement. nanoTime() but for something like animations, the speed of something, etc some people use System. If we at the same time ask System. nanoTime ()则是高精度单调计时器，适合性能测量。 Apr 14, 2022 · System. There are substantial differences between these… Explore the differences between System. to get a time from the system (not the current time ). nanoTime Jun 12, 2021 · In Java (but other platforms has a solution for this too), System. currentTimeMillis ()都是Java中重要的时间测量工具,各有其适用场景。 System. currentTimeMillis () use then? If you look at the source code of Clock. Sep 25, 2025 · 👉 If you care about measuring durations reliably, use System. Deciding between System. currentTimeMillis() used! Obviously the conversion looks a bit different as granularity of nanoTime() is higher, but it’s the same Posix call! This implies that under some circumstances System. currentTimeMillis itself is not affected by time zone. nanoTime() gives you a nanosecond-precise time, relative to some arbitrary point. bcdv jjjy ftkihc bpvqzok rtzfhh qniaaoq blx vnet cja ohth