It wouldnt work. The reason is that the DecimalFormat wouldnt format your object in any random fashion you desire. Each and every DecimalFormat object is associated to a DecimalFormatSymbols object which define the grouping seperator, thousands seperator symbols etc.
Thus when you specify a
pattern in this fashion ##,###.##, you specify that your thousand seperator is a comma and decimal seperator is a dot. By specifying a comma after every numerical digit, you cannot for instance, force the formatter to overthrow it's thousand count which will remain constant at the number of places reserved for that locale.(3 for english locale etc)
You would have to write custom code to format in the way you desire.
ram.