Note: This is major release of ICU4J. It contains bug fixes and adds implementations of inherited API and introduces new API or functionality.
For the most recent release, see the ICU4J download site.
The International Components for Unicode (ICU) library provides robust and full-featured Unicode services on a wide variety of platforms. ICU supports the most current version of the Unicode standard, including support for supplementary characters (needed for GB 18030 repertoire support).
Java provides a strong foundation for global programs, and IBM and the ICU team played a key role in providing globalization technology to Java. But because of its long release schedule, Java cannot always keep up with evolving standards. The ICU team continues to extend Java's Unicode and internationalization support, focusing on improving performance, keeping current with the Unicode standard, and providing richer APIs, while remaining as compatible as possible with the original Java text and internationalization API design.
ICU4J is an add-on to the regular JRE that provides:
Note: We continue to provide assistance to Java, and in some cases, ICU4J support has been rolled into a later release of Java. For example, BCP47 language tag support including Unicode locale extensions is now in Java 7. However, the most current and complete version is always found in ICU4J.
See the ICU 62 download page about new features in this release.
The list of API changes since the previous ICU4J release is available here.
The ICU projects (ICU4C and ICU4J) are hosted by the Unicode Consortium. The ICU binary and source files are distributed under the UNICODE DATA FILES AND SOFTWARE LICENSE. The full copy of the license and third party software licences are available in LICENSE file included in this package.
ICU4J 62 depends on J2SE 6 functionality. Therefore, ICU4J only runs on JRE version 6 or later. ICU4J 62 is tested on JRE 6, 7, 8 and 9.
There are a few different ways to download the ICU4J releases.
<dependency> <groupId>com.ibm.icu</groupId> <artifactId>icu4j</artifactId> <version>62.1</version> </dependency> <dependency> <groupId>com.ibm.icu</groupId> <artifactId>icu4j-charset</artifactId> <version>62.1</version> </dependency> <dependency> <groupId>com.ibm.icu</groupId> <artifactId>icu4j-localespi</artifactId> <version>62.1</version> </dependency>
For more details on how to download ICU4J directly from the web site, please see the ICU download page at http://www.icu-project.org/download/
Below, all directory pathes are relative to the directory where the ICU4J source archive is extracted.
Information and build files:
|readme.html||A description of ICU4J (International Components for Unicode for Java)|
|build.html||The main Ant build file for ICU4J. See How to Install and Build for more information|
ICU4J runtime class files:
|Path||Sub-component Name||Build Dependencies||Public API Packages||Description|
|Collator APIs and implementation. Also includes some public API classes that depend on Collator. This sub-component is packaged as a part of icu4j.jar.|
|ICU core API classes and implementation. This sub-component is packaged as a part of icu4j.jar.|
|main/classes/currdata||icu4j-currdata||icu4j-core||n/a||No public API classes. Provides access to currency display data. This sub-component is packaged as a part of icu4j.jar.|
|main/classes/langdata||icu4j-langdata||icu4j-core||n/a||No public API classes. Provides access to language display data. This sub-component is packaged as a part of icu4j.jar.|
|n/a||Implementation of various locale-sensitive service providers defined
|main/classes/regiondata||icu4j-regiondata||icu4j-core||n/a||No public API classes. Provides access to region display data. This sub-component is packaged as a part of icu4j.jar.|
|main/classes/translit||icu4j-translit||icu4j-core||com.ibm.icu.text||Transliterator APIs and implementation. This sub-component is packaged as a part of icu4j.jar.|
ICU4J unit test files:
|Path||Sub-component Name||Runtime Dependencies||Description|
|Test suite for charset sub-component.|
|Test suite for collate sub-component.|
|Test suite for core sub-component.|
|main/tests/framework||icu4j-test-framework||icu4j-core||Common ICU4J unit test framework and utilities.|
|Test suite for localespi sub-component.|
|Test suite for sub-component packaging.|
|Test suite for translit sub-component.|
|main/shared||Files shared by ICU4J sub-components under the
|demos||ICU4J demo programs.|
|perf-tests||ICU4J performance test files.|
|tools||ICU4J tools including:
|lib||Folder used for downloading depedency libraries.
Note: ICU4J runtime libraries do not depend on any external libraries other than JDK. These dependencies are for testing (such as JUnit).
The ICU user's guide contains lots of general information about ICU, in its C, C++, and Java incarnations.
The complete API documentation for ICU4J (javadoc) is available on the ICU4J web site, and can be built from the sources:
To install ICU4J, simply place the prebuilt jar file icu4j.jar on your Java CLASSPATH. If you need Charset API support please also place icu4j-charset.jar on your class path along with icu4j.jar.
To build ICU4J, you will need JDK 7 or later (JDK 8 is the reference envionment for this release)
and the Apache Ant version 1.9 or later. It's recommended to install both the JDK and Ant
somewhere outsidethe ICU4J directory. For example, on Linux you might install
set JAVA_HOME=C:\jdk1.8.0 set ANT_HOME=C:\apache-ant set PATH=%JAVA_HOME%\bin;%ANT_HOME%\bin;%PATH%
Once the JDK and Ant are configured, run the desired target defined in build.xml. The default target is "jar" which compiles ICU4J library class files and create ICU4J jar files. For example:
Note: The above output is an example. The numbers are likely to be different with the current version ICU4J.C:\icu4j>ant Buildfile: C:\icu4j\build.xml info: [echo] ----- Build Environment Information ------------------- [echo] Java Home: C:\jdk1.8.0\jre [echo] Java Version: 1.8.0_144 [echo] Ant Home: C:\apache-ant [echo] Ant Version: Apache Ant(TM) version 1.9.4 compiled on April 29 2014 [echo] OS: Windows 10 [echo] OS Version: 10.0 [echo] OS Arch: amd64 [echo] Host: ICUDEV [echo] ------------------------------------------------------- core: @compile: [echo] build-local: ../../shared/../../build-local.properties [echo] --- java compiler arguments ------------------------ [echo] source dir: C:\icu4j\main\classes\core/src [echo] output dir: C:\icu4j\main\classes\core/out/bin [echo] bootclasspath: [echo] classpath: [echo] source: 1.6 [echo] target: 1.6 [echo] debug: on [echo] encoding: UTF-8 [echo] compiler arg: -Xlint:all,-deprecation,-dep-ann,-options,-overrides [echo] ---------------------------------------------------- [mkdir] Created dir: C:\icu4j\main\classes\core\out\bin [javac] Compiling 415 source files to C:\icu4j\main\classes\core\out\bin [javac] Note: Some input files use or override a deprecated API. [javac] Note: Recompile with -Xlint:deprecation for details. compile: @copy: [copy] Copying 24 files to C:\icu4j\main\classes\core\out\bin [copy] Copied 4 empty directories to 3 empty directories under C:\icu4j\mai n\classes\core\out\bin set-icuconfig-datapath: copy-data: [unjar] Expanding: C:\icu4j\main\shared\data\icudata.jar into C:\icu4j\main\ classes\core\out\bin [unjar] Expanding: C:\icu4j\main\shared\data\icutzdata.jar into C:\icu4j\mai n\classes\core\out\bin ... ... ... _build-localespi: @compile: [echo] build-local: ../../shared/../../build-local.properties [echo] --- java compiler arguments ------------------------ [echo] source dir: C:\icu4j\main\classes\localespi/src [echo] output dir: C:\icu4j\main\classes\localespi/out/bin [echo] bootclasspath: [echo] classpath: C:\icu4j\main\classes\core\out\lib\icu4j-core.jar;C: \icu4j\main\classes\collate\out\lib\icu4j-collate.jar [echo] source: 1.6 [echo] target: 1.6 [echo] debug: on [echo] encoding: UTF-8 [echo] compiler arg: -Xlint:all,-deprecation,-dep-ann,-options [echo] ---------------------------------------------------- [mkdir] Created dir: C:\icu4j\main\classes\localespi\out\bin [javac] Compiling 22 source files to C:\icu4j\main\classes\localespi\out\bin compile: @copy: [copy] Copying 11 files to C:\icu4j\main\classes\localespi\out\bin copy: @jar: [mkdir] Created dir: C:\icu4j\main\classes\localespi\out\lib [copy] Copying 1 file to C:\icu4j\main\classes\localespi\out [jar] Building jar: C:\icu4j\main\classes\localespi\out\lib\icu4j-localesp i.jar jar: @src-jar: [jar] Building jar: C:\icu4j\main\classes\localespi\out\lib\icu4j-localesp i-src.jar src-jar: build: jar: [copy] Copying 1 file to C:\icu4j [copy] Copying 1 file to C:\icu4j BUILD SUCCESSFUL Total time: 30 seconds
The following are some targets that you can provide to ant.
For more targets run
ant -projecthelp or see the build.xml file.
|jar (default)||Create ICU4J runtime library jar archives (
|check||Build all ICU4J runtime library classes and corresponding unit test cases, then run the tests.|
|clean||Remove all build output files.|
|main||Build all ICU4J runtime library sub-components (under the directory
|tests||Build all ICU4J unit test sub-components (under the directory
|tools||Build the tools.|
|docs||Run javadoc over the ICU4J runtime library files, generating an HTML documentation
tree in the subdirectory
|jarDocs||Create ICU4J doc jar archive (
|jarDemos||Create ICU4J demo jar archive (
For more information, read the Ant documentation and the build.xml file.
Note: If you get an OutOfMemoryError when you are running "ant check", you can set the heap size of the jvm by setting the environment variable JVM_OPTIONS to the appropriate java options.
Eclipse users: See the ICU4J site for information on how to configure Eclipse to build and develop ICU4J on Eclipse IDE.
Note: To install and configure ICU4J Locale Service Provider, please refer the user guide page ICU4J Locale Service Provider.
Note: the demos provided with ICU4J are for the most part undocumented. This list can show you where to look, but you'll have to experiment a bit. The demos are unsupported and may change or disappear without notice.
The icu4j.jar file contains only the ICU4J runtime library classes, not the demo classes, so unless you build ICU4J there is little to try out.
java -cp $icu4j_root/icu4j.jar:$icu4j_root/icu4j-charset.jar <your program>
The other demo programs are not supported and exist only to let you experiment with the ICU4J classes. First, build ICU4J using ant jarDemos. Then launch the demos as below:
java -jar $icu4j_root/icu4jdemos.jar
By default the ICU4J distribution includes all of the standard resource information. It is located under the directory com/ibm/icu/impl/data. Depending on the service, the data is in different locations and in different formats. Note: This will continue to change from release to release, so clients should not depend on the exact organization of the data in ICU4J.
com.ibm.icu.util.ULocaleclass, and the use of these names in searching for resources is documented in
Some of the data files alias or otherwise reference data from other data files. One reason for this is because some locale names have changed. For example, he_IL used to be iw_IL. In order to support both names but not duplicate the data, one of the resource files refers to the other file's data. In other cases, a file may alias a portion of another file's data in order to save space. Currently ICU4J provides no tool for revealing these dependencies.
Localeclass silently converts the language code "he" to "iw" when you construct the Locale (for versions of Java through Java 5). Thus Java cannot be used to locate resources that use the "he" language code. ICU, on the other hand, does not perform this conversion in ULocale, and instead uses aliasing in the locale data to represent the same set of data under different locale ids.
Resource files that use locale ids form a hierarchy, with up to four
levels: a root, language, region (country), and variant. Searches for
locale data attempt to match as far down the hierarchy as possible,
for example, "he_IL" will match he_IL, but
"he_US" will match he (since there is no US
variant for he, and "xx_YY will match root (the
default fallback locale) since there is no xx language code
in the locale hierarchy. Again, see
java.util.ResourceBundle for more information.
Currently ICU4J provides no tool for revealing these dependencies between data files, so trimming the data directly in the ICU4J project is a hit-or-miss affair. The key point when you remove data is to make sure to remove all dependencies on that data as well. For example, if you remove he.res, you need to remove he_IL.res, since it is lower in the hierarchy, and you must remove iw.res, since it references he.res, and iw_IL.res, since it depends on it (and also references he_IL.res).
Unfortunately, the jar tool in the JDK provides no way to remove items from a jar file. Thus you have to extract the resources, remove the ones you don't want, and then create a new jar file with the remining resources. See the jar tool information for how to do this. Before 'rejaring' the files, be sure to thoroughly test your application with the remaining resources, making sure each required resource is present.
Warning: Resource file formats can change across releases of ICU4J! The format of ICU4J resources is not part of the API. Clients who develop their own resources for use with ICU4J should be prepared to regenerate them when they move to new releases of ICU4J.
We are still developing ICU4J's resource mechanism. Currently it is not possible to mix icu's new binary .res resources with traditional java-style .class or .txt resources. We might allow for this in a future release, but since the resource data and format is not formally supported, you run the risk of incompatibilities with future releases of ICU4J.
Resource data in ICU4J is checked in to the repository as a jar file containing the resource binaries, $icu4j_root/main/shared/data/icudata.jar. This means that inspecting the contents of these resources is difficult. They currently are compiled from ICU4C .txt file data. You can view the contents of the ICU4C text resource files to understand the contents of the ICU4J resources.
The files in icudata.jar get extracted to com/ibm/icu/impl/data in the build output directory by some build targets.
ICU4J library includes the latest time zone data, as of the release date. However, time zone data is frequently updated in response to changes made by local governments around the world. If you need to update the time zone data, please refer the ICU user guide topic Updating the Time Zone Data.
You can optionally configure ICU4J date and time service classes to use underlying JDK TimeZone implementation (see the ICU4J API reference TimeZone for the details). When this configuration is enabled, ICU's own time zone data won't be used and you have to get time zone data patches from the JRE vendor.
http://www.icu-project.org/ is the home page of International Components for Unicode development project
Your comments are important to making ICU4J successful. We are committed to investigate any bug reports or suggestions, and will use your feedback to help plan future releases.
To submit comments, request features and report bugs, please see ICU bug database information or contact us through the ICU Support mailing list. While we are not able to respond individually to each comment, we do review all comments.
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