Negative sign in case of zero in java

I think this would be a workaround to avoid -0.0. Use following code :

DecimalFormat df = new DecimalFormat("#,##0.0");
df.setRoundingMode(RoundingMode.HALF_UP);       
df.setNegativePrefix(""); // set negative prefix BLANK
String formattedValue = df.format(-0.023);
df.setNegativePrefix("-"); // set back to - again
System.out.println(formattedValue);

Output :

0.0

I don't think there's a way of doing it just with DecimalFormat, but this one-liner takes care of the problem:

formattedValue = formattedValue.replaceAll( "^-(?=0(\\.0*)?$)", "");

It removes (replaces with "") the minus sign if it's followed by 0-n characters of "0.00000...", so this will work for any similar result such as "-0", "-0." or "-0.000000000"

Here's some test code:

public static void main(String[] args) {
    System.out.println(format(-0.023));
    System.out.println(format(12.123));
    System.out.println(format(-12.345));
    System.out.println(format(-0.123));
    System.out.println(format(-1.777));
}

public static String format(double number) {
    DecimalFormat df = new DecimalFormat("#,##0.0");
    df.setRoundingMode(RoundingMode.HALF_UP);
    String formattedValue = df.format(number);
    formattedValue = formattedValue.replaceAll("^-(?=0(\\.0*)?$)", "");
    return formattedValue;
}

Output (as expected):

0.0
12.1
-12.3
-0.1
-1.8

Try this: DecimalFormat df = new DecimalFormat("#,##0.0#;(#,##0.0#)");

According to the Javadoc for DecimalFormat:

A DecimalFormat pattern contains a positive and negative subpattern, for example, "#,##0.00;(#,##0.00)". Each subpattern has a prefix, numeric part, and suffix. The negative subpattern is optional; if absent, then the positive subpattern prefixed with the localized minus sign ('-' in most locales) is used as the negative subpattern. That is, "0.00" alone is equivalent to "0.00;-0.00". If there is an explicit negative subpattern, it serves only to specify the negative prefix and suffix; the number of digits, minimal digits, and other characteristics are all the same as the positive pattern. That means that "#,##0.0#;(#)" produces precisely the same behavior as "#,##0.0#;(#,##0.0#)".

That by check if the calculated value = "-0.0" make it equal "0.0"

and you can capsulate the code sush as

public String getFormattedValue(String input) {
        DecimalFormat df = new DecimalFormat("#,##0.0");
        df.setRoundingMode(RoundingMode.HALF_UP);
        String formattedValue = df.format(input);

        if (formattedValue.equalsIgnoreCase("-0.0")) {
            formattedValue = "0.0";
        }

        System.out.println(formattedValue);
        return formattedValue;
    }