java - Format of BigDecimal number

Question

BigDecimal val = BigDecimal.valueOf(0.20);
System.out.println(a);

I want to store in val a value 0.20 and not 0.2. What I can do ?

I dont think I can use NumberFormat in this case, when I use NumberFormat I must know what the length of my decimal number is! I can have 0.20 or 0.5000, I don't know the exact length of my decimal number, so I cannot use :

DecimalFormat df = new DecimalFormat("#0.00");

or

DecimalFormat df = new DecimalFormat("#0.00000");

maybe I have just 2 numbers after point or 5 numbers or more, and this program doesn't work:

 BigDecimal a = BigDecimal.valueOf(0.20);//i give an example of 0.2 i can have 0.98...0
         System.out.println(a);

         NumberFormat nf1 = NumberFormat.getInstance();
         System.out.println(nf1.format(0.5000));

Answer 1

BigDecimal remembers the trailing zeros - with some significant side-effect:

BigDecimal bd1 = new BigDecimal("0.20"); 
BigDecimal bd2 = new BigDecimal("0.2");

System.out.println(bd1);
System.out.println(bd2);
System.out.println(bd1.equals(bd2));

will print

0.20
0.2
false

And we need to remember, that we can't use BiGDecimal for numbers, where the decimal expansion has a period:

BigDecimal.ONE.divide(new BigDecimal(3));

will throw an exception (what partially answers your concerns in your comments)