How to set customize currency in java?

I tried to make manual currency. Here is my code

DecimalFormat df = new DecimalFormat();
DecimalFormatSymbols dfs = new DecimalFormatSymbols();
dfs.setCurrencySymbol("$");
dfs.setGroupingSeparator('.');
dfs.setDecimalSeparator('.');
df.setDecimalFormatSymbols(dfs);
System.out.println(df.format(3333454));

Program output is

3.333.454

Why the currency symbol I set didn't appear?