Java add space/char to specific position in string

/**
 * @author lautturi.com
 * Java example: add char in specific position of string
 */

import java.util.*;

public class Lautturi {

	public static void main(String[] args) {

		String str = "123456789";
		str = str.substring(0, 6) + " " + str.substring(6);
		System.out.println(str);
	}

}

output

123456 789