Use java.text.DecimalFormat to format integer : Decimal « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Decimal

import java.text.DecimalFormat;

public class Main {

  public static void main(String args[]) {    
    System.out.println(new DecimalFormat("0.#####E0").format(123456));
  }
}
//1.23456E5