StringBuilder, replace

private void replace(StringBuilder sb, String strFrom, String strTo) {

    if (sb == null) return;

    if (strFrom == null) return;

    if (strTo == null) return;

    while (sb.indexOf(strFrom) > -1) {

        int idxStart = sb.indexOf(strFrom);

        sb.replace(idxStart, idxStart + strFrom.length(), strTo);

    }

}