Answers for "4 digit of double in java'"

decimal up to 6 places in java

double num = 1.34567;
System.out.format("%.4f", num);

java double to string fixed precision

Double toBeTruncated = new Double("3.5789055");

Double truncatedDouble = BigDecimal.valueOf(toBeTruncated)
    .setScale(3, RoundingMode.HALF_UP)
    .doubleValue();