Format a number with leading sign

How do I format in Java a number with its leading sign?

Negative numbers are correctly displayed with leading -, but obviously positive numbers are not displayed with +.

How to do that in Java? My current currency format string is \#\#\#,\#\#\#,\#\#\#,\#\#\#,\#\#0.00 (yes, I need to format positive/negative currency values)