public class Main {

  public static void main(String[] args) {

    // Default

    System.out.printf("%f%n", 123456.78);

    // Two decimal digits

    System.out.printf("%.2f%n", 123456.78);

​

    // No decimal digits

    System.out.printf("%.0f%n", 123456.78);

​

    // No decimal digits but keep the decimal point

    System.out.printf("%#.0f%n", 123456.78);

​

    // Group digits

    System.out.printf("%,.2f%n", 123456.78);

​

    // Scientific notation with two digits of precision

    System.out.printf("%.2e", 123456.78);

  }

}

​