If you need the charAt() function for the string format then hex is
probably better because the mapping between bytes and character
positions is much simpler than with Base64.
You mean I must use charsetName in string create? I found following
char sets using Charset.availableCharsets(), but there is no Base16
{Big5=Big5, Big5-HKSCS=Big5-HKSCS, EUC-JP=EUC-JP, EUC-KR=EUC-KR,
GB18030=GB18030, GB2312=GB2312, GBK=GBK, IBM-Thai=IBM-Thai,
IBM00858=IBM00858, IBM01140=IBM01140, IBM01141=IBM01141,
IBM01142=IBM01142, IBM01143=IBM01143, IBM01144=IBM01144,
IBM01145=IBM01145, IBM01146=IBM01146, IBM01147=IBM01147,
IBM01148=IBM01148, IBM01149=IBM01149, IBM037=IBM037, IBM1026=IBM1026,
IBM1047=IBM1047, IBM273=IBM273, IBM277=IBM277, IBM278=IBM278,
IBM280=IBM280, IBM284=IBM284, IBM285=IBM285, IBM297=IBM297,
IBM420=IBM420, IBM424=IBM424, IBM437=IBM437, IBM500=IBM500,
IBM775=IBM775, IBM850=IBM850, IBM852=IBM852, IBM855=IBM855,
IBM857=IBM857, IBM860=IBM860, IBM861=IBM861, IBM862=IBM862,
IBM863=IBM863, IBM864=IBM864, IBM865=IBM865, IBM866=IBM866,
IBM868=IBM868, IBM869=IBM869, IBM870=IBM870, IBM871=IBM871,
IBM918=IBM918, ISO-2022-CN=ISO-2022-CN, ISO-2022-JP=ISO-2022-JP,
ISO-2022-JP-2=ISO-2022-JP-2, ISO-2022-KR=ISO-2022-KR,
ISO-8859-1=ISO-8859-1, ISO-8859-13=ISO-8859-13,
ISO-8859-15=ISO-8859-15, ISO-8859-2=ISO-8859-2, ISO-8859-3=ISO-8859-3,
ISO-8859-4=ISO-8859-4, ISO-8859-5=ISO-8859-5, ISO-8859-6=ISO-8859-6,
ISO-8859-7=ISO-8859-7, ISO-8859-8=ISO-8859-8, ISO-8859-9=ISO-8859-9,
JIS_X0201=JIS_X0201, JIS_X0212-1990=JIS_X0212-1990, KOI8-R=KOI8-R,
KOI8-U=KOI8-U, Shift_JIS=Shift_JIS, TIS-620=TIS-620, US-ASCII=US-
ASCII, UTF-16=UTF-16, UTF-16BE=UTF-16BE, UTF-16LE=UTF-16LE,
UTF-32=UTF-32, UTF-32BE=UTF-32BE, UTF-32LE=UTF-32LE, UTF-8=UTF-8,
windows-1250=windows-1250, windows-1251=windows-1251,
windows-1252=windows-1252, windows-1253=windows-1253,
windows-1254=windows-1254, windows-1255=windows-1255,
windows-1256=windows-1256, windows-1257=windows-1257,
windows-1258=windows-1258, windows-31j=windows-31j, x-Big5-Solaris=x-
Big5-Solaris, x-euc-jp-linux=x-euc-jp-linux, x-EUC-TW=x-EUC-TW, x-
eucJP-Open=x-eucJP-Open, x-IBM1006=x-IBM1006, x-IBM1025=x-IBM1025, x-
IBM1046=x-IBM1046, x-IBM1097=x-IBM1097, x-IBM1098=x-IBM1098, x-
IBM1112=x-IBM1112, x-IBM1122=x-IBM1122, x-IBM1123=x-IBM1123, x-
IBM1124=x-IBM1124, x-IBM1381=x-IBM1381, x-IBM1383=x-IBM1383, x-
IBM33722=x-IBM33722, x-IBM737=x-IBM737, x-IBM834=x-IBM834, x-IBM856=x-
IBM856, x-IBM874=x-IBM874, x-IBM875=x-IBM875, x-IBM921=x-IBM921, x-
IBM922=x-IBM922, x-IBM930=x-IBM930, x-IBM933=x-IBM933, x-IBM935=x-
IBM935, x-IBM937=x-IBM937, x-IBM939=x-IBM939, x-IBM942=x-IBM942, x-
IBM942C=x-IBM942C, x-IBM943=x-IBM943, x-IBM943C=x-IBM943C, x-IBM948=x-
IBM948, x-IBM949=x-IBM949, x-IBM949C=x-IBM949C, x-IBM950=x-IBM950, x-
IBM964=x-IBM964, x-IBM970=x-IBM970, x-ISCII91=x-ISCII91, x-ISO-2022-CN-
CNS=x-ISO-2022-CN-CNS, x-ISO-2022-CN-GB=x-ISO-2022-CN-GB, x-
iso-8859-11=x-iso-8859-11, x-JIS0208=x-JIS0208, x-JISAutoDetect=x-
JISAutoDetect, x-Johab=x-Johab, x-MacArabic=x-MacArabic, x-
MacCentralEurope=x-MacCentralEurope, x-MacCroatian=x-MacCroatian, x-
MacCyrillic=x-MacCyrillic, x-MacDingbat=x-MacDingbat, x-MacGreek=x-
MacGreek, x-MacHebrew=x-MacHebrew, x-MacIceland=x-MacIceland, x-
MacRoman=x-MacRoman, x-MacRomania=x-MacRomania, x-MacSymbol=x-
MacSymbol, x-MacThai=x-MacThai, x-MacTurkish=x-MacTurkish, x-
MacUkraine=x-MacUkraine, x-MS950-HKSCS=x-MS950-HKSCS, x-mswin-936=x-
mswin-936, x-PCK=x-PCK, x-UTF-16LE-BOM=x-UTF-16LE-BOM, X-UTF-32BE-
BOM=X-UTF-32BE-BOM, X-UTF-32LE-BOM=X-UTF-32LE-BOM, x-windows-50220=x-
windows-50220, x-windows-50221=x-windows-50221, x-windows-874=x-
windows-874, x-windows-949=x-windows-949, x-windows-950=x-windows-950,
x-windows-iso2022jp=x-windows-iso2022jp}