Using group separators. : Formatter Specifiers « Development « Java Tutorial

1. Java Tutorial
2. Development
3. Formatter Specifiers

import java.util.Formatter;

public class Main {
  public static void main(String[] argv) throws Exception {
    Formatter fmt = new Formatter();

    fmt.format("No group separators: %d\n", 123456789);
    fmt.format("With group separators: %,d\n\n", 123456789);
    System.out.println(fmt);
  }
}
/*No group separators: 123456789
With group separators: 123,456,789


*/