The minimum field width specifier by applying it to the %f conversion : Formatter Field Width « Development « Java Tutorial

1. Java Tutorial
2. Development
3. Formatter Field Width

import java.util.Formatter;

public class MainClass {
  public static void main(String args[]) {
    Formatter fmt = new Formatter();

    fmt.format("|%f|%n|%12f|%n|%012f|", 10.12345, 10.12345, 10.12345);

    System.out.println(fmt);

  }
}

|10.123450|
|   10.123450|
|00010.123450|