NumberFormat.getInstance() : Number Format « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Number Format

import java.text.NumberFormat;

public class MainClass {

  public static void main(String[] args) {

    NumberFormat nf = NumberFormat.getInstance();
    for (double x = Math.PI; x < 100000; x *= 10) {
      String formattedNumber = nf.format(x);
      System.out.println(formattedNumber + "\t" + x);
    }
  }
}

3.142	3.141592653589793
31.416	31.41592653589793
314.159	314.1592653589793
3,141.593	3141.5926535897934
31,415.927	31415.926535897932