Java BigDecimal Issue

Question

I want to convert String "0.955000" to "0.96" using Java DecimalFormat

Here's my code snippet:

String inputVal = "0.955000";
DecimalFormat decFmt = new DecimalFormat("0.00")
decFmt.setRoundingMode(RoundingMode.HALF_UP);
String outputVal = decFmt.format(Double.valueof(inputVal));

Here I get the output value as "0.95". I was expecting output to be "0.96". Does anyone know what's wrong in my code? And is there a way, I can get "0.96" using decimal format.

Your title talk about an issue with `BigDecimal`, but your code doesn't use it. With what do you need help? — Tunaki, Jun 24 '16 at 20:21
To tack onto @Tunaki 's answer, if you were using BigDecimal, you could use the `.setScale(..)` method and accomplish what you want. — lucasvw, Jun 24 '16 at 20:22
Why using `DecimalFormat` to perform the rounding which `BigDecimal` supports this directly. If you want to do your own rounding you may as well use `double`. — Peter Lawrey, Jun 24 '16 at 20:39
Possible duplicate of [RoundingMode.HALF\_DOWN issue in Java8](http://stackoverflow.com/questions/30778927/roundingmode-half-down-issue-in-java8) — Xiong Chiamiov, Jun 24 '16 at 21:51

Wael · Answer 1 · 2016-06-24T21:07:35.357

2

This is the code I tried:

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


public class Test
{
  public static void main(String[] args)
  {
    String inputVal      = "0.955000";
    DecimalFormat decFmt = new DecimalFormat("0.00");
    decFmt.setRoundingMode(RoundingMode.HALF_UP);
    String outputVal = decFmt.format(Double.valueOf(inputVal));
    System.out.println(outputVal);
  }
}

The output I got using jdk 7 is 0.96 but with jdk 8 I got 0.95.

Here is why: 0.955 as double is: 0.9549999833106995 in IEEE binary format

The round half up will become: 0.95 which is the correct answer.

edited Jun 24 '16 at 21:07

answered Jun 24 '16 at 20:29

Wael

1,533
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1

I get 0.95 when I run your code using 1.8.0_40 – azurefrog Jun 24 '16 at 20:40
This is similar to the following question: http://stackoverflow.com/questions/30778927/roundingmode-half-down-issue-in-java8 – Wael Jun 24 '16 at 21:03
Thanks for your answer. Got the issue now. – Suvan Piya Jun 27 '16 at 14:44

score 0 · Answer 2 · answered Jun 24 '16 at 21:07

0

Found the issue with this. Earlier I was trying with Java 7 and was getting 0.96. Now after changing to Java 8, I got it as 0.95. I thinks it's a Java version issue. Java 7 and 8 are behaving differently for Decimal Format.

answered Jun 24 '16 at 21:07

Suvan Piya

9

The correct output is 0.95 and not 0.96 this is because the double is stored in IEEE binary format. See my update above – Wael Jun 24 '16 at 21:08

Java BigDecimal Issue

2 Answers2