Change the decimal separator is set to "." : Decimal « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Decimal

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

public class Main {
  public static void main(String args[]) {
    double d = 123456.7890;
    DecimalFormat df = new DecimalFormat("#####0.00");
    DecimalFormatSymbols dfs = df.getDecimalFormatSymbols();

    dfs.setDecimalSeparator('.');
    df.setDecimalFormatSymbols(dfs);
    System.out.println(df.format(d));
  }
}