Altering number of decimal places of formatted number

Using http://java.sun.com/docs/books/tutorial/i18n/format/numberFormat.html I have worked out how to format a number, almost. When I follow the example in this tutorial that shows how format a double, it always rounds it to 3 decimal places. How do I alter the number of decimal places that this formatting procedure outputs? I used the US as the locale and English as the language. I am assuming that if these parameters are chosen, 3 decimal places is the output. Is this assumption correct?

[500 byte] By [carparka] at [2007-10-3 10:37:50]