please post the code snippet for the program that are given in the text box

String source = "Hello world";
int i, len = source.length();
StringBuffer dest = new StringBuffer(len);

for (i = (len - 1); i >= 0; i--)
{
  if (i == 0)
  {
    dest.append(source.charAt(len - 1));
  }
  else
  {
    if (i == (len - 1))
    {
      dest.append(source.charAt(0));
    }
    else
    {
      dest.append(source.charAt(i));
    }
  }
}

System.out.println(dest.toString());