Precision of mathamatical operation of data of double data type

Java - double data precision

import java.math.BigDecimal;

public class Main {
	
	public static void main(String[] args){
		double dNum = .012 ;
		double sumNum = dNum + dNum + dNum;
		System.out.println("Result : " + sumNum );
		
		//convert the double to string
		String sNum = Double.toString(dNum);
		//pass sNum to BigDecimal
		BigDecimal bigVal = new BigDecimal(sNum);
		
		
		bigVal = bigVal.add(bigVal).add(bigVal);
		//precise value
		System.out.println("Big Decimal Value : " + bigVal);
		
	}

}