RoundOffError

RoundOffError.java

import java.math.BigDecimal;
import java.math.RoundingMode;

public class RoundOffError {

    private static final int DEVIDE_DECIMAL_SCALE = 20;
    private static final int CALC_DECIMAL_SCALE = 10;

    public static void main(String[] args) {
        BigDecimal num3000  = new BigDecimal(3000);
        BigDecimal num12000 = new BigDecimal(12000);
        BigDecimal num64    = new BigDecimal(64);

        BigDecimal hiritu1  = num64.divide(num12000, DEVIDE_DECIMAL_SCALE, RoundingMode.HALF_UP);
        BigDecimal result1  = hiritu1.multiply(num3000);
        int int1            = result1.intValue();
        BigDecimal decimal1 = result1.subtract(new BigDecimal(int1));
        System.out.println("hiritu1  [" + hiritu1.scale() + "][" + hiritu1.precision() + "] = " + hiritu1.toPlainString());
        System.out.println("result1  [" + result1.scale() + "][" + result1.precision() + "] = " + result1.toPlainString());
        System.out.println("int1              = " + int1);
        System.out.println("decimal1 [" + decimal1.scale() + "][" + decimal1.precision() + "] = " + decimal1.toPlainString());

        System.out.println();

        BigDecimal hiritu2  = num3000.divide(num12000, DEVIDE_DECIMAL_SCALE, RoundingMode.HALF_UP);
        BigDecimal result2  = hiritu2.multiply(num64);
        int int2            = result2.intValue();
        BigDecimal decimal2 = result2.subtract(new BigDecimal(int2));
        System.out.println("hiritu2  [" + hiritu2.scale() + "][" + hiritu2.precision() + "] = " + hiritu2.toPlainString());
        System.out.println("result2  [" + result2.scale() + "][" + result2.precision() + "] = " + result2.toPlainString());
        System.out.println("int2              = " + int2);
        System.out.println("decimal2 [" + decimal2.scale() + "][" + decimal2.precision() + "] = " + decimal2.toPlainString());
    }
}