Java example which replaces character present at particular position

public class StringTest {


    public static void main(String[] args)
    {
        int i =0;
        for(char c: test.toCharArray())
        {
            System.out.println(i++ + "=" + c);
        }
       
        String sample = "akckekghkjklmnopqrstuvwxyz";
        System.out.println(sample);
        char c = sample.charAt(10);
        System.out.println(c);
        System.out.println("test "+sample.substring(0, 10));
        System.out.println(getStringByReplacingTenthPosition(sample).length());

    }

    private static String getStringByReplacingTenthPosition(String sample) {
        return sample.substring(0, 10) + " " + sample.substring(11);
    }
}