Something

    public static String replaceChar(String theString, String starString,  String newChar)
    {
        int foundPos = -2;
        int foundCount = 0; 
        String newString = "";
        while((foundPos = theString.indexOf(newChar, foundPos + 1)) != -1)
        {
            String newWord = starString.substring(0, foundPos);
            String newWord2 = starString.substring(foundPos + 1, theString.length());
            starString = newWord + newChar + newWord2;
        }
        newString = starString;

        return newString;
    }