Use a DecimalFormatter:

double number = 0.9999999999999;
DecimalFormat numberFormat = new DecimalFormat("#.00");
System.out.println(numberFormat.format(number));

Will give you "0.99". You can add or subtract 0 on the right side to get more or less decimals.

Or use '#' on the right to make the additional digits optional, as in with #.## (0.30) would drop the trailing 0 to become (0.3).

That code will die a horrible death if the division has a non-terminating decimal expansion. See javadoc of divide(BigDecimal divisor):

if the exact quotient cannot be represented (because it has a non-terminating decimal expansion) an ArithmeticException is thrown.

Example:

BigDecimal one = BigDecimal.ONE;
BigDecimal x = BigDecimal.valueOf(7);
one.divide(x); // throws java.lang.ArithmeticException: Non-terminating decimal expansion; no exact representable decimal result.

Use one of the other overloads of divide(), e.g. divide(BigDecimal divisor, int scale, RoundingMode roundingMode):

BigDecimal one = BigDecimal.ONE;
BigDecimal x = BigDecimal.valueOf(7);
BigDecimal quotient = one.divide(x, 5, RoundingMode.HALF_UP);
System.out.println(quotient); // prints: 0.14286

BigDecimal one = BigDecimal.ONE;
BigDecimal x = BigDecimal.valueOf(7);
BigDecimal quotient = one.divide(x, 30, RoundingMode.HALF_UP);
System.out.println(quotient); // prints: 0.142857142857142857142857142857

    public static String format(Double d, int decimalPlace) {
        String pattern = "0." + String.format("%0" + decimalPlace + "d", 0);
        DecimalFormat df = new DecimalFormat(pattern);
        return df.format(d);
    }

Example

• format(12.345124,1) -> 12.3
• format(12.345124,2) -> 12.34
• format(12.345124,3) -> 12.345
• format(12.345124,4) -> 12.3451