Name: jl125535 Date: 02/27/2002


FULL PRODUCT VERSION :
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)


FULL OPERATING SYSTEM VERSION : Windows NT Version 4.0
(Build 1381, Service Pack 5)


A DESCRIPTION OF THE PROBLEM :
We use a dll to do some calculations. It is a C-dll calling
a Delphi-dll (pascal).
With one call to an standard arithmetic function in the
Delphi-dll (int(..)), returning to the Java VM and calling
an DecimalFormat.format, the Java VM will crash with
an "EXCEPTION_FLT_DIVIDE_BY_ZERO occurred at PC=0xADBD38".

The crash occures in DecimalFormat.format()
...
boolean isNegative = (number < 0.0) || (number == 0.0 &&
1/number < 0.0);
...
while dividing "1/number", if number is 0.0 (which is
normally allowed in Java -> Infinity).

The arithmetic function "int()" in the dll cuts the
fractional part of the number, so we assume a problem with
the floating point unit, but without any help we can't
verify that.
The "frac()"-function causes the same problem.
Without calling that functions, all works fine.

There is one other testcase, where we had a crash in the
awt.dll in older JDK-Versions, but this does not happen
with the actual version (1.4).
I think, that there is a relation between these crashes.
We have a complete small testcase for both problems.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Load external C-/Delphi-dll
2. Call external method, which uses described arithmetic
function ("int()" or "frac()")
3. Create an DecimalFormatter
4. Use DecimalFormat.format with an value of 0.0

ERROR MESSAGES/STACK TRACES THAT OCCUR :
C:\testdelphi>java test.TestDelphiDll
TestDelphiDll: TSTDELPH.DLL geladen
calling test_DelphiCall() ...
Java_test_TestDelphiDll_JniTestDelphi() calling ...
Laden der Bibliothek lva32.dll!
Calling function entry() ...
entryRet = 456832
Java_test_TestDelphiDll_JniTestDelphi() finishing ...
test_DelphiCall() called ...
Now DecimalFormat.format ...

Unexpected Signal : EXCEPTION_FLT_DIVIDE_BY_ZERO occurred at PC=0xADBD38
Function=[Unknown.]
Library=(N/A)

NOTE: We are unable to locate the function name symbol for the error
      just occurred. Please refer to release documentation for possible
      reason and solutions.


Current Java thread:

Dynamic libraries:
0x00400000 - 0x00406000 c:\java\j2sdk1.4.0\bin\java.exe
0x77F70000 - 0x77FD0000 C:\WINNT\System32\ntdll.dll
0x77DC0000 - 0x77DFF000 C:\WINNT\system32\ADVAPI32.dll
0x77F00000 - 0x77F62000 C:\WINNT\system32\KERNEL32.dll
0x77E70000 - 0x77EC4000 C:\WINNT\system32\USER32.dll
0x77ED0000 - 0x77EFC000 C:\WINNT\system32\GDI32.dll
0x77E10000 - 0x77E67000 C:\WINNT\system32\RPCRT4.dll
0x78000000 - 0x78046000 C:\WINNT\system32\MSVCRT.dll
0x6D330000 - 0x6D442000 c:\java\j2sdk1.4.0\jre\bin\client\jvm.dll
0x77FD0000 - 0x77FFB000 C:\WINNT\System32\WINMM.dll
0x72FE0000 - 0x72FE8000 C:\WINNT\System32\mmdrv.dll
0x6BC00000 - 0x6BC17000 C:\WINNT\System32\sb16snd.dll
0x71700000 - 0x7178A000 C:\WINNT\system32\COMCTL32.dll
0x6D1D0000 - 0x6D1D7000 c:\java\j2sdk1.4.0\jre\bin\hpi.dll
0x6D300000 - 0x6D30D000 c:\java\j2sdk1.4.0\jre\bin\verify.dll
0x6D210000 - 0x6D228000 c:\java\j2sdk1.4.0\jre\bin\java.dll
0x6D320000 - 0x6D32D000 c:\java\j2sdk1.4.0\jre\bin\zip.dll
0x10000000 - 0x10033000 C:\testdelphi\tstdelph.dll
0x0AEC0000 - 0x0AED3000 C:\testdelphi\lva32.dll
0x65340000 - 0x653D2000 C:\WINNT\system32\oleaut32.dll
0x77B80000 - 0x77C36000 C:\WINNT\system32\ole32.dll
0x41000000 - 0x4100B000 C:\testdelphi\borlndmm.dll
0x76AE0000 - 0x76AFD000 C:\WINNT\System32\imagehlp.dll
0x731B0000 - 0x731BA000 C:\WINNT\System32\PSAPI.DLL

Local Time = Tue Feb 26 16:15:45 2002


****************
Another exception has been detected while we were handling last error.
Dumping information about last error:
ERROR REPORT FILE = (N/A)
PC = 0x00ADBD38
SIGNAL = -1073741682
FUNCTION NAME = (N/A)
OFFSET = 0xFFFFFFFF
LIBRARY NAME = (N/A)
Please check ERROR REPORT FILE for further information, if there is any.
Good bye.


This bug can be reproduced always.

---------- BEGIN SOURCE ----------
We have a complete little testcase to reproduce the bug. Please ask for it.

The Java-Programm looks like:
import java.text.*;
import java.util.*;

public class TestDelphiDll
{
  private native int JniTestDelphi();

  public TestDelphiDll()
  {
    test_DelphiCall();
  }

  public static void main(String args[])
  {
    TestDelphiDll testDelphiDll1 = new TestDelphiDll();
    System.exit(0);
  }

  private void test_DelphiCall()
  {
    System.out.println("calling test_DelphiCall() ...");

    JniTestDelphi();

    System.out.println("test_DelphiCall() called ...");

    Double wertObject = new Double("0");
    double wertPre = wertObject.doubleValue();
    double wert = Math.abs(wertPre);

    DecimalFormat formatter;
    NumberFormat numberformat = NumberFormat.getInstance();
    if(numberformat instanceof DecimalFormat)
    {
      formatter = (DecimalFormat)numberformat;
    }
    else
    {
      NumberFormat numberformat1 = NumberFormat.getInstance(Locale.US);
      if(numberformat1 instanceof DecimalFormat)
        formatter = (DecimalFormat)numberformat1;
      else
        throw new Error("Could not get a DecimalFormat for the current
locale!!");
    }

    DecimalFormat decimalformat = (DecimalFormat)formatter.clone();
    StringBuffer stringbuffer = new StringBuffer();
    FieldPosition fieldposition = new FieldPosition(1);
    decimalformat.setMaximumFractionDigits(1000);
    decimalformat.setMinimumFractionDigits(0);

    // Now Division by zero
    System.out.println("Now DecimalFormat.format ...");
    decimalformat.format(wert, stringbuffer, fieldposition);
  }

  static
  {
      try
      {
          System.loadLibrary("TSTDELPH");
          System.out.println("TestDelphiDll: TSTDELPH.DLL geladen");
      }
      catch(UnsatisfiedLinkError e)
      {
          e.printStackTrace();
      }
  }
}

---------- END SOURCE ----------

CUSTOMER WORKAROUND :

======================================================================

You can patch the DecimalFormat-Class by detecting the sign
bit without Division by zero.

boolean isNegative = (number < 0.0) ||
        (number == 0.0 && (Double.doubleToLongBits(number)
& 0x8000000000000000L) != 0L);
        if (isNegative) number = -number;

Btw: Isn't this version not better for detecting the sign-
bit ?
(Review ID: 143369)