FULL PRODUCT VERSION :
Under Windows2000Professional: java version "1.4.2_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_02-b03)
Java HotSpot(TM) Client VM (build 1.4.2_02-b03, mixed mode)

Under HP-UX: Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1.10-030630-10:50)
Java HotSpot(TM) Server VM (build 1.3.1 1.3.1.10-_30_jun_2003_11_52 PA2.0, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows 2000 [Version 5.00.2195] (checked bug with java.version=1.4.2_02)
HP-UX B.11.11 U 9000/800 1113474677 (checked bug with java.runtime.version=1.3.1.10-030630-10:50)

A DESCRIPTION OF THE PROBLEM :
The class java.text.DecimalFormat with #0.00 pattern fail rounding.
It fails when the centesimal number is par, is correct otherwise (odd).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Make instace of java.text.DecimalFormat("#0.00") and then try to round the double value 0.025 (or every other number with decimal number par, i.e 0.045 0.065 ...)


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
    n=0.024 : 0.02
    n=0.025 : 0.03 <== see here
    n=0.026 : 0.03
    ...
    ...
    n=0.034 : 0.03
    n=0.035 : 0.04
    n=0.036 : 0.04
    
ACTUAL -
    n=0.024 : 0.02
    n=0.025 : 0.02 <== MUST BE 0.3
    n=0.026 : 0.03
    ...
    ...
    n=0.034 : 0.03
    n=0.035 : 0.04 <== IS OK!
    n=0.036 : 0.04
    

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.text.DecimalFormat;

/**
 *
 * @author Daniele Belli <a href=mailto:###@###.###>Daniele Belli</a>
 * The pourpose of this class is to show a bug of DecimalFormat class.<br>
 * This tester class print a table of number from 0.000 to 0.999 and its rounded number to two decimal from 0.00 to 1.00<br>
 * using #0.00 format string.<br>
 *
 * The bug is in rounding (for example): <br>
    n=0.024 : 0.02 <br>
    n=0.025 : 0.02 <== MUST BE 0.3 <br>
    n=0.026 : 0.03 <br>
    ... <br>
    ... <br>
    n=0.034 : 0.03 <br>
    n=0.035 : 0.04 <== IS OK! <br>
    n=0.036 : 0.04 <br><br>
    
    Seems that with a decimal number odd the round of number hundredth is correct.<br>
    Instead of with a par decimal number the round fails.
    
 */

public class DecimalFormatTester {
    
    public DecimalFormatTester() {
        
        int multiplier = 1000;
        double n=0;
        
        DecimalFormat df=new DecimalFormat("#0.00");
        
        for (int i=1 ; i<multiplier ; i++) {
            
            n = i/ ((double) multiplier) ;
            System.out.println("n=" + n + "\t : " + df.format(n) );
        }

    }
    
    public static void main (String args[]) {
        System.getProperties().list(System.out);
        new DecimalFormatTester();
    }
}


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