Date: Fri, 9 Jul 1999 16:04:32 -0600 From: Nate Williams <nate@mt.sri.com> To: Martin Dieringer <dieringe@zedat.fu-berlin.de> Cc: Nate Williams <nate@mt.sri.com>, Stephen McKay <syssgm@detir.qld.gov.au>, freebsd-java@FreeBSD.ORG Subject: Re: strange java calculation errors Message-ID: <199907092204.QAA09955@mt.sri.com> In-Reply-To: <Pine.BSF.4.10.9907092353330.44163-100000@ThinkPad.nowhere.local> References: <199907091530.JAA05956@mt.sri.com> <Pine.BSF.4.10.9907092353330.44163-100000@ThinkPad.nowhere.local>
next in thread | previous in thread | raw e-mail | index | archive | help
> > > >I use the latest jdk1.1.8_ELF.V99-6-3.tar.gz with applied net-patch.
> > > >On a few-weeks-old 3.2-STABLE.
> > > >I have strange arithmetic errors. I sometimes get NaN-s
> > > >and very big numbers (...E306) which don't appear on any other machine/os
> > > >and don't appear with the linux-jdk1.2 pre-v2.
> > >
> > > We are getting occasional failures in the GregorianCalendar routines.
> > > For some inexplicable reason it is full of floating point calculations.
> > > Every so often, one of these calculations is wildly incorrect, and we
> > > get an ArrayIndexOutOfBoundsException (when looking up the month in
> > > an array). We have a little bit of trace showing one of the statements
> > > returning 0 or 9223372036854775807 sometimes (instead of an expected
> > > result of a few thousand).
> >
> > As always, unless we can reproduce this bug, it's almost impossible to
> > track down. If you can provide us a test case, there is a very good
> > chance we can fix this.
>
>
> Ok, I set up a sample program. I think it needs to be an awt-application.
> I don't get any errors without setVisible(), but with a visible frame
> I get errors every few seconds. It has to be a Thread, too, I think.
> Probably you know how to track this down further.
This is great, thanks Martin! I'm able to reproduce this error running
your program on my box.
Unfortunately, I won't be able to look at it anytime soon as I'm going
on vacation next week, but maybe when I get back!
Again, thanks for simple test. This makes our job *much* easier.
Nate
> Martin
>
>
> //BugTest.java ----------------------------------------------
>
> import java.awt.*;
> import java.util.Random;
>
> public class BugTest extends Frame implements Runnable
> {
>
> Random random = new Random();
>
> double weight;
> double denom;
> double meatEnergy;
> double weightgain;
>
> public BugTest(){
> setSize(100,100);
> setVisible(true);
> }
>
>
> public void run(){
> while (true){
> try{
> calc();
> } catch (ArithmeticException a) {
> System.err.println("weight: "+ weight + "\ndenom: "+ denom);
> a.printStackTrace();
> }
> }
> }
>
> void calc() throws ArithmeticException {
> weight = random.nextDouble()*10.;
> meatEnergy= 0.029994563969828213;
> denom = (.0836 * Math.pow(weight, 1.37));
> weightgain = .2849372 * meatEnergy * weight / denom;
> if (weightgain > 1000.)
> throw new ArithmeticException("weightgain "+weightgain);
> }
>
> public static void main(String args[]){
> BugTest bug = new BugTest();
> Thread bugThread = new Thread(bug);
> bugThread.setPriority(Thread.MIN_PRIORITY);
> bugThread.start();
> }
>
> }
>
> //------------------------------------------------------
>
>
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-java" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199907092204.QAA09955>