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What is the Java equivalent of DateTime.Ticks in C#?

DateTime dt = new DateTime(2010, 9, 14, 0, 0, 0); Console.WriteLine("Ticks: {0}", dt.Ticks);

What will be the equivalent of above mentioned code in Java?

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7 Answers 7

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Well, java.util.Date/Calendar only have precision down to the millisecond:

Calendar calendar = Calendar.getInstance(); calendar.set(Calendar.MILLISECOND, 0); // Clear the millis part. Silly API. calendar.set(2010, 8, 14, 0, 0, 0); // Note that months are 0-based Date date = calendar.getTime(); long millis = date.getTime(); // Millis since Unix epoch

That's the nearest effective equivalent. If you need to convert between a .NET ticks value and a Date/Calendar you basically need to perform scaling (ticks to millis) and offsetting (1st Jan 1AD to 1st Jan 1970).

Java's built-in date and time APIs are fairly unpleasant. I'd personally recommend that you use Joda Time instead. If you could say what you're really trying to do, we can help more.

EDIT: Okay, here's some sample code:

import java.util.*; public class Test { private static final long TICKS_AT_EPOCH = 621355968000000000L; private static final long TICKS_PER_MILLISECOND = 10000; public static void main(String[] args) { long ticks = 634200192000000000L; Date date = new Date((ticks - TICKS_AT_EPOCH) / TICKS_PER_MILLISECOND); System.out.println(date); TimeZone utc = TimeZone.getTimeZone("UTC"); Calendar calendar = Calendar.getInstance(utc); calendar.setTime(date); System.out.println(calendar); } }

Note that this constructs a Date/Calendar representing the UTC instant of 2019/9/14. The .NET representation is somewhat fuzzy - you can create two DateTime values which are the same except for their "kind" (but therefore represent different instants) and they'll claim to be equal. It's a bit of a mess :(

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6 Comments

In my current scenario i had saved Ticks value calculated in C#; now what i want is read that tick value and get the same date in Java.
@Asoo: Okay. Walking to work ATM - code in twenty minutes. Basically divide by ticks per millisecond and subtract an offset. You should also bear timezone offsets in mind.
Thanks @Skeet....But if i want to calculate the ticks in Java and read them in C#.....i tried this but it does not gives the identical value: TimeZone utc = TimeZone.getTimeZone("UTC"); Calendar calendar = Calendar.getInstance(utc); calendar.set(2010,8,14,0,0,0); System.out.println(calendar.getTimeInMillis() * TICKS_PER_MILLISECOND + TICKS_AT_EPOCH);
@Asoo: It looks like it's keeping the existing millis-in-second value - call calendar.set(Calendar.MILLISECOND, 0); before the other call to calendar.set(). I'll update my answer.
There's a tiny, tiny, tiny improvement you could make, if you added 5000 to (ticks - TICKS_AT_EPOCH) before you divide by TICKS_PER_MILLISECOND. Then you'd be rounding to the nearest millisecond instead of truncating down.
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In Java is:

long TICKS_AT_EPOCH = 621355968000000000L; long tick = System.currentTimeMillis()*10000 + TICKS_AT_EPOCH;
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2 Comments

using Local zone (analogue of DateTime.Now.Ticks) long tick = (System.currentTimeMillis() + TimeZone.getDefault().getRawOffset()) * 10000 + TICKS_AT_EPOCH;
@Alex78191 has pointed out a good (missing) point as in answer. Time Zone must be considered otherwise will not calculate correct current time outside of GMT. "import java.util.*" is required to compile suggested change.
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System.nanoTime() gives you nanoseconds in Java (since 1.6). You'll still need to shift/rescale, but no precision will be lost.

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nanoTime has nothing with clock time, which means it can't be converted or compared with Ticks from .net DateTime. Here is quote from javadoc: This method can only be used to measure elapsed time and is not related to any other notion of system or wall-clock time. The value returned represents nanoseconds since some fixed but arbitrary time (perhaps in the future, so values may be negative).
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Base on Jon Skeet I developed this class

import java.util.Calendar; import java.util.Date; public class DateHelper { private static final long TICKS_AT_EPOCH = 621355968000000000L; private static final long TICKS_PER_MILLISECOND = 10000; public static long getUTCTicks(Date date){ Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return (calendar.getTimeInMillis() * TICKS_PER_MILLISECOND) + TICKS_AT_EPOCH; } public static Date getDate(long UTCTicks){ return new Date((UTCTicks - TICKS_AT_EPOCH) / TICKS_PER_MILLISECOND); } }

It works for me

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2 Comments

this is the only one that worked for me? maybe i was missing something!
+1 It works, although the method names have totally nothing to do with UTC. Just Ticks from Date and Date from Ticks. This is useful for an Android app written in Xamarin, the DB libraries store DateTime as ticks in the DB - this works for it.
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There are 10,000 ticks in a millisecond, and C# considers the beginning of time January 1, 0001 at midnight. Here's a one-liner which converts an Instant to ticks.

public static long toTicks(Instant i) { return Duration.between(Instant.parse("0001-01-01T00:00:00.00Z"), i).toMillis() * 10000; }
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A tick is a 100 nanoseconds.
Whoops! Fixed the answer. Thanks for the callout. I think the code snippet was correct. Does it seem fine to you?
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And for those of us showing up trying to get the current number of ticks as defined by the UUID specification:

/** Returns the current tick count. Ticks are the number of 100 ns intervals since October 15, 1582 @return */ private static long getUtcNowTicks() { final long UNIX_EPOCH_TICKS = 122192928000000000L; //Number of ticks from 10/16/1582 to 1/1/1970 Instant i = Clock.systemUTC().instant(); //get the current time long ticks = UNIX_EPOCH_TICKS; // number of ticks as of 1/1/1970 ticks += i.getEpochSecond()*10000000; //number of whole seconds (converted to ticks) since 1/1/1970 ticks += i.getNano() / 100; //number of ticks since the start of the second return ticks; /* Some interesting tick values Date Ticks ========== ================== 10/15/1582 0 Start of UUID epoch; the date we switched to the Gregorian calendar) 1/01/1601 5748192000000000 Start of Windows epoch (start of 1st Gregorian 400-year cycle) 12/30/1899 100101312000000000 Start of Lotus 123, Excel, VB, COM, Delphi epoch 1/01/1900 100103040000000000 Start of SQL Server epoch 1/01/1970 122192928000000000 Start of UNIX epoch 1/01/2000 131659776000000000 1/01/2010 134815968000000000 1/01/2020 137971296000000000 1/19/2038 143714420469999999 UNIX Y2k38 problem (January 19, 2038 3:14:07 am) */ }
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To convert .Net Ticks to millis in java use this :

static final long TICKS_PER_MILLISECOND = 10000; long ticks = 450000000000L; // sample tick value long millis = (ticks / TICKS_PER_MILLISECOND);
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Different epoch in C#/Java - see Pablo's answer