Format currency without currency symbol

The following works. It's a bit ugly, but it fulfils the contract:

NumberFormat nf = NumberFormat.getCurrencyInstance();
DecimalFormatSymbols decimalFormatSymbols = ((DecimalFormat) nf).getDecimalFormatSymbols();
decimalFormatSymbols.setCurrencySymbol("");
((DecimalFormat) nf).setDecimalFormatSymbols(decimalFormatSymbols);
System.out.println(nf.format(12345.124).trim());

You could also get the pattern from the currency format, remove the currency symbol, and reconstruct a new format from the new pattern:

NumberFormat nf = NumberFormat.getCurrencyInstance();
String pattern = ((DecimalFormat) nf).toPattern();
String newPattern = pattern.replace("\u00A4", "").trim();
NumberFormat newFormat = new DecimalFormat(newPattern);
System.out.println(newFormat.format(12345.124));

Set it with an empty string instead:

DecimalFormat formatter = (DecimalFormat) NumberFormat.getCurrencyInstance(Locale.US);
DecimalFormatSymbols symbols = formatter.getDecimalFormatSymbols();
symbols.setCurrencySymbol(""); // Don't use null.
formatter.setDecimalFormatSymbols(symbols);
System.out.println(formatter.format(12.3456)); // 12.35