1. Internationalization Guide
  2. Supported Encodings

2 Supported Encodings

The java.io.InputStreamReader, java.io.OutputStreamWriter, java.lang.String classes, and classes in the java.nio.charset package can convert between Unicode and a number of other character encodings. The supported encodings vary between different implementations of the Java SE Platform. The class description for java.nio.charset.Charset lists the encodings that any implementation of the Java SE platform is required to support.

The following tables show the encoding sets supported by this version of the Oracle Java SE platform. The canonical names used by the java.nio APIs are in many cases not the same as those used in the java.io and java.lang APIs.

Basic Encoding Set (contained in java.base module)

Canonical Name for java.nio API Canonical Name for java.io API and java.lang API Alias or Aliases Description
CESU-8 CESU8 CESU8 csCESU-8 Unicode CESU-8
GB18030 GB18030 gb18030-2022 or gb18030-2000 if the system property and value jdk.charset.GB18030=2000 are specified Simplified Chinese, PRC standard
IBM00858 Cp858 cp858 ccsid00858 cp00858 858 PC-Multilingual-850+euro Variant of Cp850 with Euro character
IBM437 Cp437 cp437 ibm437 ibm-437 437 cspc8codepage437 windows-437 MS-DOS United States, Australia, New Zealand, South Africa
IBM775 Cp775 cp775 ibm775 ibm-775 775 PC Baltic
IBM850 Cp850 cp850 ibm-850 ibm850 850 cspc850multilingual MS-DOS Latin-1
IBM852 Cp852 cp852 ibm852 ibm-852 852 csPCp852 MS-DOS Latin-2
IBM855 Cp855 cp855 ibm-855 ibm855 855 cspcp855 IBM Cyrillic
IBM857 Cp857 cp857 ibm857 ibm-857 857 csIBM857 IBM Turkish
IBM862 Cp862 cp862 ibm862 ibm-862 862 csIBM862 cspc862latinhebrew PC Hebrew
IBM866 Cp866 cp866 ibm866 ibm-866 866 csIBM866 MS-DOS Russian
ISO-8859-1 ISO8859_1 iso-ir-100 ISO_8859-1 latin1 l1 IBM819 cp819 csISOLatin1 819 IBM-819 ISO8859_1 ISO_8859-1:1987 ISO_8859_1 8859_1 ISO8859-1 ISO-8859-1, Latin Alphabet No. 1
ISO-8859-13 ISO8859_13 iso8859_13 8859_13 iso_8859-13 ISO8859-13 Latin Alphabet No. 7
ISO-8859-15 ISO8859_15 ISO_8859-15 Latin-9 csISO885915 8859_15 ISO-8859-15 ISO8859_15 ISO8859-15 IBM923 IBM-923 cp923 923 LATIN0 LATIN9 L9 csISOlatin0 csISOlatin9 ISO8859_15_FDIS Latin Alphabet No. 9
ISO-8859-16 ISO8859_16 iso-ir-226 ISO_8859-16:2001 ISO_8859-16 latin10 l10 csISO885916 Latin Alphabet No. 10 or South-Eastern European
ISO-8859-2 ISO8859_2 iso8859_2 8859_2 iso-ir-101 ISO_8859-2 ISO_8859-2:1987 ISO8859-2 latin2 l2 ibm912 ibm-912 cp912 912 csISOLatin2 Latin Alphabet No. 2
ISO-8859-4 ISO8859_4 iso8859_4 iso8859-4 8859_4 iso-ir-110 ISO_8859-4 ISO_8859-4:1988 latin4 l4 ibm914 ibm-914 cp914 914 csISOLatin4 Latin Alphabet No. 4
ISO-8859-5 ISO8859_5 iso8859_5 8859_5 iso-ir-144 ISO_8859-5 ISO_8859-5:1988 ISO8859-5 cyrillic ibm915 ibm-915 cp915 915 csISOLatinCyrillic Latin/Cyrillic Alphabet
ISO-8859-7 ISO8859_7 iso8859_7 8859_7 iso-ir-126 ISO_8859-7 ISO_8859-7:1987 ELOT_928 ECMA-118 greek greek8 csISOLatinGreek sun_eu_greek ibm813 ibm-813 813 cp813 iso8859-7 Latin/Greek Alphabet (ISO-8859-7:2003)
ISO-8859-9 ISO8859_9 iso8859_9 8859_9 iso-ir-148 ISO_8859-9 ISO_8859-9:1989 ISO8859-9 latin5 l5 ibm920 ibm-920 920 cp920 csISOLatin5 Latin Alphabet No. 5
KOI8-R KOI8_R koi8_r koi8 cskoi8r KOI8-R, Russian
KOI8-U KOI8_U koi8_u KOI8-U, Ukrainian
US-ASCII ASCII iso-ir-6 ANSI_X3.4-1986 ISO_646.irv:1991 ASCII ISO646-US us IBM367 cp367 csASCII default 646 iso_646.irv:1983 ANSI_X3.4-1968 ascii7 American Standard Code for Information Interchange
UTF-16 UTF-16 UTF_16 utf16 unicode UnicodeBig Sixteen-bit Unicode (or UCS) Transformation Format, byte order identified by an optional byte-order mark
UTF-16BE UnicodeBigUnmarked UTF_16BE ISO-10646-UCS-2 X-UTF-16BE UnicodeBigUnmarked Sixteen-bit Unicode (or UCS) Transformation Format, big-endian byte order
UTF-16LE UnicodeLittleUnmarked UTF_16LE X-UTF-16LE UnicodeLittleUnmarked Sixteen-bit Unicode (or UCS) Transformation Format, little-endian byte order
UTF-32 UTF-32 UTF_32 UTF32 32-bit Unicode (or UCS) Transformation Format, byte order identified by an optional byte-order mark
UTF-32BE UTF-32BE UTF_32BE X-UTF-32BE 32-bit Unicode (or UCS) Transformation Format, big-endian byte order
UTF-32LE UTF-32LE UTF_32LE X-UTF-32LE 32-bit Unicode (or UCS) Transformation Format, little-endian byte order
UTF-8 UTF8 UTF8 unicode-1-1-utf-8 Eight-bit Unicode (or UCS) Transformation Format
windows-1250 Cp1250 cp1250 cp5346 Windows Eastern European
windows-1251 Cp1251 cp1251 cp5347 ansi-1251 Windows Cyrillic
windows-1252 Cp1252 cp1252 cp5348 ibm-1252 ibm1252 Windows Latin-1
windows-1253 Cp1253 cp1253 cp5349 Windows Greek
windows-1254 Cp1254 cp1254 cp5350 Windows Turkish
windows-1257 Cp1257 cp1257 cp5353 Windows Baltic
x-IBM737 Cp737 cp737 ibm737 ibm-737 737 PC Greek
x-IBM874 Cp874 cp874 ibm874 ibm-874 874 IBM Thai
x-UTF-16LE-BOM UnicodeLittle UnicodeLittle Sixteen-bit Unicode (or UCS) Transformation Format, little-endian byte order, with byte-order mark
X-UTF-32BE-BOM X-UTF-32BE-BOM UTF_32BE_BOM UTF-32BE-BOM 32-bit Unicode (or UCS) Transformation Format, big-endian byte order, with byte-order mark
X-UTF-32LE-BOM X-UTF-32LE-BOM UTF_32LE_BOM UTF-32LE-BOM 32-bit Unicode (or UCS) Transformation Format, little-endian byte order, with byte-order mark

 

Extended Encoding Set (contained in jdk.charsets module)

Canonical Name for java.nio API Canonical Name for java.io API and java.lang API Alias or Aliases Description
Big5 Big5 csBig5 Big5, Traditional Chinese
Big5-HKSCS Big5_HKSCS Big5_HKSCS big5hk big5-hkscs big5hkscs Big5 with Hong Kong extensions, Traditional Chinese (incorporating 2001 revision)
EUC-JP EUC_JP euc_jp eucjis eucjp Extended_UNIX_Code_Packed_Format_for_Japanese csEUCPkdFmtjapanese x-euc-jp x-eucjp JISX 0201, 0208 and 0212, EUC encoding Japanese
EUC-KR EUC_KR euc_kr ksc5601 euckr ks_c_5601-1987 ksc5601-1987 ksc5601_1987 ksc_5601 csEUCKR 5601 KS C 5601, EUC encoding, Korean
GB2312 EUC_CN gb2312 gb2312-80 gb2312-1980 euc-cn euccn x-EUC-CN EUC_CN GB2312, EUC encoding, Simplified Chinese
GBK GBK windows-936 CP936 GBK, Simplified Chinese
IBM01140 Cp1140 cp1140 ccsid01140 cp01140 1140 ebcdic-us-037+euro Variant of Cp037 with Euro character
IBM01141 Cp1141 cp1141 ccsid01141 cp01141 1141 ebcdic-de-273+euro Variant of Cp273 with Euro character
IBM01142 Cp1142 cp1142 ccsid01142 cp01142 1142 ebcdic-no-277+euro ebcdic-dk-277+euro Variant of Cp277 with Euro character
IBM01143 Cp1143 cp1143 ccsid01143 cp01143 1143 ebcdic-fi-278+euro ebcdic-se-278+euro Variant of Cp278 with Euro character
IBM01144 Cp1144 cp1144 ccsid01144 cp01144 1144 ebcdic-it-280+euro Variant of Cp280 with Euro character
IBM01145 Cp1145 cp1145 ccsid01145 cp01145 1145 ebcdic-es-284+euro Variant of Cp284 with Euro character
IBM01146 Cp1146 cp1146 ccsid01146 cp01146 1146 ebcdic-gb-285+euro Variant of Cp285 with Euro character
IBM01147 Cp1147 cp1147 ccsid01147 cp01147 1147 ebcdic-fr-277+euro Variant of Cp297 with Euro character
IBM01148 Cp1148 cp1148 ccsid01148 cp01148 1148 ebcdic-international-500+euro Variant of Cp500 with Euro character
IBM01149 Cp1149 cp1149 ccsid01149 cp01149 1149 ebcdic-s-871+euro Variant of Cp871 with Euro character
IBM037 Cp037 cp037 ibm037 ebcdic-cp-us ebcdic-cp-ca ebcdic-cp-wt ebcdic-cp-nl csIBM037 cs-ebcdic-cp-us cs-ebcdic-cp-ca cs-ebcdic-cp-wt cs-ebcdic-cp-nl ibm-037 ibm-37 cpibm37 037 USA, Canada (Bilingual, French), Netherlands, Portugal, Brazil, Australia
IBM1026 Cp1026 cp1026 ibm1026 ibm-1026 1026 IBM Latin-5, Turkey
IBM1047 Cp1047 cp1047 ibm-1047 1047 Latin-1 character set for EBCDIC hosts
IBM273 Cp273 cp273 ibm273 ibm-273 273 IBM Austria, Germany
IBM277 Cp277 cp277 ibm277 ibm-277 277 IBM Denmark, Norway
IBM278 Cp278 cp278 ibm278 ibm-278 278 ebcdic-sv ebcdic-cp-se csIBM278 IBM Finland, Sweden
IBM280 Cp280 cp280 ibm280 ibm-280 280 IBM Italy
IBM284 Cp284 cp284 ibm284 ibm-284 284 csIBM284 cpibm284 IBM Catalan/Spain, Spanish Latin America
IBM285 Cp285 cp285 ibm285 ibm-285 285 ebcdic-cp-gb ebcdic-gb csIBM285 cpibm285 IBM United Kingdom, Ireland
IBM290 Cp290 cp290 ibm290 ibm-290 csIBM290 EBCDIC-JP-kana 290 IBM Japanese Katakana Host Extended SBCS
IBM297 Cp297 cp297 ibm297 ibm-297 297 ebcdic-cp-fr cpibm297 csIBM297 IBM France
IBM420 Cp420 cp420 ibm420 ibm-420 ebcdic-cp-ar1 420 csIBM420 IBM Arabic
IBM424 Cp424 cp424 ibm424 ibm-424 424 ebcdic-cp-he csIBM424 IBM Hebrew
IBM500 Cp500 cp500 ibm500 ibm-500 500 ebcdic-cp-ch ebcdic-cp-bh csIBM500 EBCDIC 500V1
IBM860 Cp860 cp860 ibm860 ibm-860 860 csIBM860 MS-DOS Portuguese
IBM861 Cp861 cp861 ibm861 ibm-861 861 csIBM861 cp-is MS-DOS Icelandic
IBM863 Cp863 cp863 ibm863 ibm-863 863 csIBM863 MS-DOS Canadian French
IBM864 Cp864 cp864 ibm864 ibm-864 864 csIBM864 PC Arabic
IBM865 Cp865 cp865 ibm865 ibm-865 865 csIBM865 MS-DOS Nordic
IBM868 Cp868 cp868 ibm868 ibm-868 868 cp-ar csIBM868 MS-DOS Pakistan
IBM869 Cp869 cp869 ibm869 ibm-869 869 cp-gr csIBM869 IBM Modern Greek
IBM870 Cp870 cp870 ibm870 ibm-870 870 ebcdic-cp-roece ebcdic-cp-yu csIBM870 IBM Multilingual Latin-2
IBM871 Cp871 cp871 ibm871 ibm-871 871 ebcdic-cp-is csIBM871 IBM Iceland
IBM918 Cp918 cp918 ibm-918 918 ebcdic-cp-ar2 IBM Pakistan (Urdu)
IBM-Thai Cp838 cp838 ibm838 ibm-838 838 IBM Thailand extended SBCS
ISO-2022-CN ISO2022CN ISO2022CN csISO2022CN GB2312 and CNS11643 in ISO 2022 CN form, Simplified and Traditional Chinese (conversion to Unicode only)
ISO-2022-JP ISO2022JP iso2022jp jis csISO2022JP jis_encoding csjisencoding JIS X 0201, 0208, in ISO 2022 form, Japanese
ISO-2022-JP-2 ISO2022JP2 csISO2022JP2 iso2022jp2 JIS X 0201, 0208, 0212 in ISO 2022 form, Japanese
ISO-2022-KR ISO2022KR ISO2022KR csISO2022KR ISO 2022 KR, Korean
ISO-8859-3 ISO8859_3 iso8859_3 8859_3 ISO_8859-3:1988 iso-ir-109 ISO_8859-3 ISO8859-3 latin3 l3 ibm913 ibm-913 cp913 913 csISOLatin3 Latin Alphabet No. 3
ISO-8859-6 ISO8859_6 iso8859_6 8859_6 iso-ir-127 ISO_8859-6 ISO_8859-6:1987 ISO8859-6 ECMA-114 ASMO-708 arabic ibm1089 ibm-1089 cp1089 1089 csISOLatinArabic Latin/Arabic Alphabet
ISO-8859-8 ISO8859_8 iso8859_8 8859_8 iso-ir-138 ISO_8859-8 ISO_8859-8:1988 ISO8859-8 cp916 916 ibm916 ibm-916 hebrew csISOLatinHebrew Latin/Hebrew Alphabet
JIS_X0201 JIS_X0201 JIS0201 JIS_X0201 X0201 csHalfWidthKatakana JIS X 0201
JIS_X0212-1990 JIS0212 JIS0212 jis_x0212-1990 x0212 iso-ir-159 csISO159JISX02121990 JIS X 0212
Shift_JIS SJIS sjis shift_jis shift-jis ms_kanji x-sjis csShiftJIS Shift-JIS, Japanese
TIS-620 TIS620 tis620 tis620.2533 TIS620, Thai
windows-1255 Cp1255 cp1255 Windows Hebrew
windows-1256 Cp1256 cp1256 Windows Arabic
windows-1258 Cp1258 cp1258 Windows Vietnamese
windows-31j MS932 MS932 windows-932 csWindows31J Windows Japanese
x-Big5-HKSCS-2001 x-Big5-HKSCS-2001 Big5_HKSCS_2001 big5hk-2001 big5-hkscs-2001 big5-hkscs:unicode3.0 big5hkscs-2001 Big5 with Hong Kong Supplementary Character Set, 2001 revision
x-Big5-Solaris Big5_Solaris Big5_Solaris Big5 with seven additional Hanzi ideograph character mappings for the Solaris zh_TW.BIG5 locale
x-euc-jp-linux EUC_JP_LINUX euc_jp_linux euc-jp-linux JISX 0201, 0208, EUC encoding Japanese
x-eucJP-Open EUC_JP_Solaris EUC_JP_Solaris eucJP-open JISX 0201, 0208, 0212, EUC encoding Japanese
x-EUC-TW EUC_TW euc_tw euctw cns11643 EUC-TW CNS11643 (Plane 1-7,15), EUC encoding, Traditional Chinese
x-IBM1006 Cp1006 cp1006 ibm1006 ibm-1006 1006 IBM AIX Pakistan (Urdu)
x-IBM1025 Cp1025 cp1025 ibm1025 ibm-1025 1025 IBM Multilingual Cyrillic: Bulgaria, Bosnia, Herzegovinia, Macedonia (FYR)
x-IBM1046 Cp1046 cp1046 ibm1046 ibm-1046 1046 IBM Arabic - Windows
x-IBM1097 Cp1097 cp1097 ibm1097 ibm-1097 1097 IBM Iran (Farsi)/Persian
x-IBM1098 Cp1098 cp1098 ibm1098 ibm-1098 1098 IBM Iran (Farsi)/Persian (PC)
x-IBM1112 Cp1112 cp1112 ibm1112 ibm-1112 1112 IBM Latvia, Lithuania
x-IBM1122 Cp1122 cp1122 ibm1122 ibm-1122 1122 IBM Estonia
x-IBM1123 Cp1123 cp1123 ibm1123 ibm-1123 1123 IBM Ukraine
x-IBM1124 Cp1124 cp1124 ibm1124 ibm-1124 1124 IBM AIX Ukraine
x-IBM1129 Cp1129 cp1129 ibm1129 ibm-1129 1129 IBM AIX Vietnamese
x-IBM1166 Cp1166 cp1166 ibm1166 ibm-1166 1166 IBM Cyrillic Multilingual with euro for Kazakhstan
x-IBM1364 Cp1364 cp1364 ibm1364 ibm-1364 1364 IBM EBCDIC KS X 1005-1
x-IBM1381 Cp1381 cp1381 ibm1381 ibm-1381 1381 IBM OS/2, DOS People's Republic of China (PRC)
x-IBM1383 Cp1383 cp1383 ibm1383 ibm-1383 1383 ibmeuccn ibm-euccn cpeuccn IBM AIX People's Republic of China (PRC)
x-IBM300 Cp300 cp300 ibm300 ibm-300 300 IBM Japanese Latin Host Double-Byte
x-IBM33722 Cp33722 cp33722 ibm33722 ibm-33722 ibm-5050 ibm-33722_vascii_vpua 33722 IBM-eucJP - Japanese (superset of 5050)
x-IBM833 Cp833 cp833 ibm833 ibm-833 IBM Korean Host Extended SBCS
x-IBM834 Cp834 cp834 ibm834 834 ibm-834 IBM EBCDIC DBCS-only Korean
x-IBM856 Cp856 cp856 ibm-856 ibm856 856 IBM Hebrew
x-IBM875 Cp875 cp875 ibm875 ibm-875 875 IBM Greek
x-IBM921 Cp921 cp921 ibm921 ibm-921 921 IBM Latvia, Lithuania (AIX, DOS)
x-IBM922 Cp922 cp922 ibm922 ibm-922 922 IBM Estonia (AIX, DOS)
x-IBM930 Cp930 cp930 ibm930 ibm-930 930 Japanese Katakana-Kanji mixed with 4370 UDC, superset of 5026
x-IBM933 Cp933 cp933 ibm933 ibm-933 933 Korean Mixed with 1880 UDC, superset of 5029
x-IBM935 Cp935 cp935 ibm935 ibm-935 935 Simplified Chinese Host mixed with 1880 UDC, superset of 5031
x-IBM937 Cp937 cp937 ibm937 ibm-937 937 Traditional Chinese Host miexed with 6204 UDC, superset of 5033
x-IBM939 Cp939 cp939 ibm939 ibm-939 939 Japanese Latin Kanji mixed with 4370 UDC, superset of 5035
x-IBM942 Cp942 cp942 ibm942 ibm-942 942 IBM OS/2 Japanese, superset of Cp932
x-IBM942C Cp942C cp942C ibm942C ibm-942C 942C cp932 ibm932 ibm-932 932 x-ibm932 Variant of Cp942
x-IBM943 Cp943 cp943 ibm943 ibm-943 943 IBM OS/2 Japanese, superset of Cp932 and Shift-JIS
x-IBM943C Cp943C cp943C ibm943C ibm-943C 943C Variant of Cp943
x-IBM948 Cp948 cp948 ibm948 ibm-948 948 OS/2 Chinese (Taiwan) superset of 938
x-IBM949 Cp949 cp949 ibm949 ibm-949 949 PC Korean
x-IBM949C Cp949C cp949C ibm949C ibm-949C 949C Variant of Cp949
x-IBM950 Cp950 cp950 ibm950 ibm-950 950 PC Chinese (Hong Kong, Taiwan)
x-IBM964 Cp964 cp964 ibm964 ibm-964 ibm-euctw 964 AIX Chinese (Taiwan)
x-IBM970 Cp970 cp970 ibm970 ibm-970 ibm-eucKR 970 AIX Korean
x-ISCII91 ISCII91 iscii ST_SEV_358-88 iso-ir-153 csISO153GOST1976874 ISCII91 ISCII91 encoding of Indic scripts
x-ISO-2022-CN-CNS ISO2022CN_CNS ISO2022CN_CNS ISO-2022-CN-CNS CNS11643 in ISO 2022 CN form, Traditional Chinese (conversion from Unicode only)
x-ISO-2022-CN-GB ISO2022CN_GB ISO2022CN_GB ISO-2022-CN-GB GB2312 in ISO 2022 CN form, Simplified Chinese (conversion from Unicode only)
x-iso-8859-11 x-iso-8859-11 iso-8859-11 iso8859_11 Latin/Thai Alphabet
x-JIS0208 JIS0208 JIS0208 JIS_C6226-1983 iso-ir-87 x0208 JIS_X0208-1983 csISO87JISX0208 JIS X 0208
x-JISAutoDetect JISAutoDetect JISAutoDetect Detects and converts from Shift-JIS, EUC-JP, ISO 2022 JP (conversion to Unicode only)
x-Johab x-Johab ksc5601-1992 ksc5601_1992 ms1361 johab Korean, Johab character set
x-MacArabic MacArabic MacArabic Macintosh Arabic
x-MacCentralEurope MacCentralEurope MacCentralEurope Macintosh Latin-2
x-MacCroatian MacCroatian MacCroatian Macintosh Croatian
x-MacCyrillic MacCyrillic MacCyrillic Macintosh Cyrillic
x-MacDingbat MacDingbat MacDingbat Macintosh Dingbat
x-MacGreek MacGreek MacGreek Macintosh Greek
x-MacHebrew MacHebrew MacHebrew Macintosh Hebrew
x-MacIceland MacIceland MacIceland Macintosh Iceland
x-MacRoman MacRoman MacRoman Macintosh Roman
x-MacRomania MacRomania MacRomania Macintosh Romania
x-MacSymbol MacSymbol MacSymbol Macintosh Symbol
x-MacThai MacThai MacThai Macintosh Thai
x-MacTurkish MacTurkish MacTurkish Macintosh Turkish
x-MacUkraine MacUkraine MacUkraine Macintosh Ukraine
x-MS932_0213 x-MS950-HKSCS MS932-0213 MS932_0213 MS932:2004 windows-932-0213 windows-932:2004 Shift_JISX0213 Windows MS932 Variant
x-MS950-HKSCS MS950_HKSCS MS950_HKSCS Windows Traditional Chinese with Hong Kong extensions
x-MS950-HKSCS-XP x-mswin-936 MS950_HKSCS_XP HKSCS Windows XP Variant
x-mswin-936 MS936 ms936 ms_936 Windows Simplified Chinese
x-PCK PCK pck Solaris version of Shift_JIS
x-SJIS_0213 x-SJIS_0213 sjis-0213 sjis_0213 sjis:2004 sjis_0213:2004 shift_jis_0213:2004 shift_jis:2004 Shift_JISX0213
x-windows-50220 MS50220 ms50220 cp50220 Windows Codepage 50220 (7-bit implementation)
x-windows-50221 MS50221 ms50221 cp50221 Windows Codepage 50221 (7-bit implementation)
x-windows-874 MS874 ms874 ms-874 windows-874 Windows Thai
x-windows-949 MS949 ms949 windows949 windows-949 ms_949 Windows Korean
x-windows-950 MS950 ms950 windows-950 Windows Traditional Chinese
x-windows-iso2022jp windows-iso2022jp windows-iso2022jp Variant ISO-2022-JP (MS932 based)

Printing Charset Information

The following application prints the aliases of each charset supported by Java SE:

import java.nio.charset.*; 

class DisplayCharsetAliases {
    public static void main(String[] args) {
        System.out.println("Charset -> Aliases");
        System.out.println("==================");
        for (Charset cs : Charset.availableCharsets().values()) {
            System.out.println(cs.name() + " -> " + cs.aliases());
        }
    }
}

Default Charset

The default charset is UTF-8. However, in JDK 17 and earlier releases, the default charset depends on the host and the user.

Standard Java APIs use the default charset unless you specify one. These APIs include:

  • In the package java.io, the classes InputStreamReader, FileReader, OutputStreamWriter, FileWriter, and PrintStream, which define constructors to create readers, writers, and print streams that encode or decode using the default charset
  • In the package java.util, the classes Formatter and Scanner, which define constructors whose results use the default charset

Note:

The standard output stream System.out and the standard error output stream System.err don't use the default charset; they use the charset specified by Console.charset().

Specify the encoding for System.out and System.err with the system properties stdout.encoding and stderr.encoding, respectively. The default values of these system properties depend on the platform. The default values take on the value of the native.encoding property when the platform does not provide streams for the console.

Default Charset for JDK 17 and Earlier Releases

In JDK 17 and earlier releases, the default charset is determined when the Java runtime starts. On macOS, the default charset is UTF-8 except in the POSIX C locale. On other operating systems, it depends on the user's locale and the default encoding. For example, on Windows, it's a codepage-based charset such as windows-1252 or windows-31j. The method java.nio.charsets.Charset.defaultCharset() returns the default charset.

You can run the following command to determine the default charset of your JDK:

java -XshowSettings:properties -version 2>&1 | grep file.encoding

Changing the JDK's Default Charset

You can set the value of the file.encoding system property on the command line to one of the following values to specify that the JDK's default charset is UTF-8 or the default charset is determined as in JDK 17 and ealier releases:

  • UTF-8: The default charset is UTF-8.
  • COMPAT: The default charset is determined as in JDK 17 and earlier releases.

Other values for file.encoding are not supported.

Note:

Before deploying your application on a JDK whose default charset is UTF-8, check if it has any charset issues by running it on a JDK whose default charset is not UTF-8 with the following command:
java -Dfile.encoding=UTF-8 <your application>

Running Java Applications on JDK Whose Default Charset Is Determined by Environment

JDK 17 introduced the system property native.encoding. Use this property to obtain the underlying host environment's character encoding name, especially if you specified that your JDK determines the default charset as in JDK 17 and earlier releases.

Note:

Setting the value of the system property native.encoding through the command line or with the method System.setProperty() has no effect.

The following example obtains the default charset from the system property native.encoding. Note that you can run this example on any JDK release; if the system property native.encoding hasn't been defined, then the example obtains the default charset from the method Charset.defaultCharset(): 

String encoding = System.getProperty("native.encoding");
Charset cs = (encoding != null) ? Charset.forName(encoding) : Charset.defaultCharset();

If your application expects the default charset to be determined as in JDK 17 and earlier releases, then use this obtained charset as a constructor argument for objects that rely on a charset, for example:

var reader = new FileReader("file.txt", cs);

Note:

The method call Charset.forName("default") throws an UnsupportedCharsetException. Use Charset.forName("US-ASCII") or Charset.defaultCharset() instead. (In JDK 17 and earlier releases, Charset.forName("default") produces the same result as Charset.forName("US-ASCII").)

The value of native.encoding affects the value of file.encoding:

  • If file.encoding is set to COMPAT on the command line, then the run-time value of file.encoding will be the same as the run-time value of native.encoding.
  • If file.encoding is set to UTF-8 on the command line, then the run-time value of file.encoding may differ from the run-time value of native.encoding.

Ensuring Source File Encoding Is Compatible with Your JDK

The javac compiler assumes that .java source files are encoded with the default charset unless configured otherwise with the -encoding option.

Consequently, before compiling an application on a JDK whose default charset is UTF-8, check for charset issues by compiling your application with the following command:

javac -encoding UTF-8 <source files of your application>

Alternatively, if you prefer to save your source files with an encoding other than UTF-8, specify in the -encoding option the value of the native.encoding system property.