FULL PRODUCT VERSION :
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
If I am using rounding half down, and have a number that ends with 5(half), then the output of the formattor will be incorrect.
For example:
new DecimalFormat("#,##0.0000");
Double toFormat = 10.55555;
the output will be 10.5556, and I am expecting 10.5555.

REGRESSION. Last worked in version 7u75

ADDITIONAL REGRESSION INFORMATION:
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a DecimalFormat like this:
DecimalFormat format = new DecimalFormat("#,##0.0000");
Set rounding half down
format.setRoundingMode(RoundingMode.HALF_DOWN);
Give this number to format:
Double toFormat = 10.55555;
Call the method format(Object obj) on the formatter

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
10.5555
ACTUAL -
10.5556

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package testjava8;

import java.math.RoundingMode;
import java.text.DecimalFormat;

/**
 * Created by cristian.nandrean on 6/11/2015.
 */
public class Formatori {

    public static void main(String[] args) {
        DecimalFormat format = new DecimalFormat("#,##0.0000");
        format.setRoundingMode(RoundingMode.HALF_DOWN);
        Double toFormat = 10.55555;
        System.out.println("Round down");
        System.out.println(format.format(toFormat));//working BAD (is a BUG)

        format.setRoundingMode(RoundingMode.HALF_UP);
        toFormat = 10.55555;
        System.out.println("Round up");
        System.out.println(format.format(toFormat));//working GOOD
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
There isn't one.