Name: gm110360 Date: 09/30/2002


FULL PRODUCT VERSION :
java version "1.4.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-b21)
Java HotSpot(TM) Client VM (build 1.4.1-b21, mixed mode)


FULL OPERATING SYSTEM VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

ADDITIONAL OPERATING SYSTEMS :

We tested against Linux and Solaris and did not see the bug.


A DESCRIPTION OF THE PROBLEM :
After calling Math.round(double) a number of times,
including some calls to Math.round(Double.NaN), subsequent
calls to Math.round(double) may incorrectly return 0.

There are a number of ways to reproduce this, but the
easiest thing to do is just to call Math.round(Double.NaN)
2000 times. The next time you call Math.round(double) the
result will always be 0, regardless of what you supply as
an argument.

Math.round(float) seems to be affected also.


REGRESSION. Last worked in version 1.4

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Make 2000 calls to Math.round(Double.NaN)
2. Make one call to Math.round(double) using a whole number
argument (e.g. 1d or 12345d)


EXPECTED VERSUS ACTUAL BEHAVIOR :
The result is 0 when it should be equal to the argument
(e.g. 1 or 12345)

ERROR MESSAGES/STACK TRACES THAT OCCUR :
We discovered this bug after experiencing the following two exceptions during
calls to Graphics.drawLine() somewhere inside the paint method of one of our
components:

sun.dc.pr.PRException: endPath: bad path
        at sun.dc.pr.Rasterizer.endPath(Rasterizer.java:537)
        at sun.java2d.pipe.DuctusRenderer.createShapeRasterizer
(DuctusRenderer.java:374)
        at sun.java2d.pipe.DuctusShapeRenderer.renderPath
(DuctusShapeRenderer.java:57)
        at sun.java2d.pipe.DuctusShapeRenderer.draw(DuctusShapeRenderer.java:45)
        at sun.java2d.pipe.PixelToShapeConverter.drawLine
(PixelToShapeConverter.java:34)
        at sun.java2d.SunGraphics2D.drawLine(SunGraphics2D.java:1954)
        ...



sun.dc.pr.PRError: setPenT4: invalid pen transformation (singular)
        at sun.dc.pr.PathStroker.setPenT4(Native Method)
        at sun.dc.pr.Rasterizer.setPenT4(Rasterizer.java:205)
        at sun.java2d.pipe.DuctusRenderer.createShapeRasterizer
(DuctusRenderer.java:260)
        at sun.java2d.pipe.DuctusShapeRenderer.renderPath
(DuctusShapeRenderer.java:57)
        at sun.java2d.pipe.DuctusShapeRenderer.draw(DuctusShapeRenderer.java:45)
        at sun.java2d.pipe.PixelToShapeConverter.drawLine
(PixelToShapeConverter.java:34)
        at sun.java2d.SunGraphics2D.drawLine(SunGraphics2D.java:1954)
        ...


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class MathBugTest {
  
  public static void main(String[] args) {
    System.out.println(Math.round(1d)); // prints "1", as expected
    for (int i=0; i<2000; i++) {
      Math.round(Double.NaN);
    }
    System.out.println(Math.round(1d)); // prints "0", which is wrong
  }
  
}
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Hack the java.lang.Math.round(float/double) methods so that
they test for NaN prior to calling StrictMath.round()

Release Regression From : 1.4.0_02
The above release value was the last known release where this
bug was known to work. Since then there has been a regression.

(Review ID: 165064)
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