DecimalFormat and doubles

Question

DecimalFormat parses Double.toString() representation (which could be in scientific and financial format).

Why Sun has chosen this approach, instead of direct converting double to String?

PS: To be more concrete. Why DecimalFormat internally uses Double.toString() in order to format Double, instead of formatting internal representation of Double itself?

Answer 1

DecimalFormat gives you more control over the format by allowing you to give it a formatting pattern.

Answer 2

may be he ask like "Double.toString(withSomeParameters)" will do the job instead of using DecimalFormat.

i think the reason, could be i18n. in some places you can type 1,800.39 .. while somewhere else you can type 1.800,39

Answer 3

I'm not shure what you mean by "direct converting", but toString() is always a debug information only! You should not use it to display values in a frontend. Use DecimalFormat for parsing and formatting!

Answer 4

For financial applications, use BigDecimal instead, that give you control over rounding modes and precision.

Answer 5

Perhaps Sun is following DRY principles.