Name: rmT116609 Date: 05/14/2003


FULL PRODUCT VERSION :
java version "1.4.1_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1_02-b06)
Java HotSpot(TM) Client VM (build 1.4.1_02-b06, mixed mode)

java version "1.4.2-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-beta-b19)
Java HotSpot(TM) Client VM (build 1.4.2-beta-b19, mixed mode)

FULL OS VERSION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
java.math.BigDecimal does not implement Banker's Rounding (round half to even) correctly. Some values will not be rounded correctly, such as
  1.15 rounded to 1 decimal
  1.275 rounded to 2 decimals

This is probably the root cause to Bug ID 4848133 "NumberFormat.format() not using ROUND_HALF_EVEN".

The bug is a huge problem when implementing an accounting system. Workaround would be highly appreciated.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run provided source code.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected output:
1.28
1.24
2.26
1.2
1.2
ACTUAL -
Actual output:
1.27
1.24
2.25
1.1
1.2

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.math.BigDecimal;

public class BigDecimalBug
{
  public static void main(String[] args)
  {
    System.out.println(new BigDecimal(1.275).setScale(2,BigDecimal.ROUND_HALF_EVEN).toString());
    System.out.println(new BigDecimal(1.235).setScale(2,BigDecimal.ROUND_HALF_EVEN).toString());
    System.out.println(new BigDecimal(2.255).setScale(2,BigDecimal.ROUND_HALF_EVEN).toString());

    System.out.println(new BigDecimal(1.15).setScale(1,BigDecimal.ROUND_HALF_EVEN).toString());
    System.out.println(new BigDecimal(1.25).setScale(1,BigDecimal.ROUND_HALF_EVEN).toString());
  }
}

---------- END SOURCE ----------
(Review ID: 185793)
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