Re: new Date(), System.currentTimeMillis() and system clock accuracy

From:

Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>

Newsgroups:

comp.lang.java.help

Date:

Sat, 05 Jul 2008 17:25:55 -0700

Message-ID:

<4870110e$0$13518$7836cce5@newsrazor.net>

Numeron wrote:

jonbbbb wrote:

[snip]
Looks like it only handles 10ms on Windows Xp:
[snip]

Thanks for the speedy reply that was only posted like 10 minutes
ago :)

It seems then that on this machine the problem is unsolvable without
trying to simulate ~1ms in a busy method. Something which is not only
difficult, but really bad programming practice (busy methods are the
devil on many computers). Not cool. I see that the Thread class has a
sleep(millis) method. Is there any way to query how long a thread has
been sleeping (I dont see anything obvious in the api), and if so is
this any more accurate than the system clock?

-Numeron

Thread.sleep() is also constrained by the system clock resolution, as
well as by arbitrary scheduling algorithms. The truth is that
Thread.sleep() gives up control for at *least* n milliseconds.

If you really need more precise timing, you may have to find/write some
JNI code that creates a low-level timer with more resolution than the OS
defaults. This code is likely to be extremely system specific.

I don't think there is any way to do what you want to do in pure Java.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>