Installing Java Modules

System Compatibility

Java modules are regularly built and tested on macOS and Linux distributions.

Java Compatibility

Java modules are compatible with JDK 8 and above. Currently, JDK 8, 11, 17, and 18 are tested in CI.

When using Java 9 or later, some JDK internals must be exposed by adding --add-opens=java.base/java.nio=ALL-UNNAMED to the java command:

# Directly on the command line
$ java --add-opens=java.base/java.nio=ALL-UNNAMED -jar ...
# Indirectly via environment variables
$ env _JAVA_OPTIONS="--add-opens=java.base/java.nio=ALL-UNNAMED" java -jar ...

Otherwise, you may see errors like module java.base does not "opens java.nio" to unnamed module.

If using Maven and Surefire for unit testing, this argument must be added to Surefire as well.

Installing from Maven

By default, Maven will download from the central repository: https://repo.maven.apache.org/maven2/org/apache/arrow/

Configure your pom.xml with the Java modules needed, for example: arrow-vector, and arrow-memory-netty.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.example</groupId>
    <artifactId>demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <arrow.version>9.0.0</arrow.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.arrow</groupId>
            <artifactId>arrow-vector</artifactId>
            <version>${arrow.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.arrow</groupId>
            <artifactId>arrow-memory-netty</artifactId>
            <version>${arrow.version}</version>
        </dependency>
    </dependencies>
</project>

To use the Arrow Flight dependencies, also add the os-maven-plugin plugin. This plugin generates useful platform-dependent properties such as os.detected.name and os.detected.arch needed to resolve transitive dependencies of Flight.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.example</groupId>
    <artifactId>demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <arrow.version>9.0.0</arrow.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.arrow</groupId>
            <artifactId>flight-core</artifactId>
            <version>${arrow.version}</version>
        </dependency>
    </dependencies>
    <build>
        <extensions>
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>1.7.0</version>
            </extension>
        </extensions>
    </build>
</project>

The --add-opens flag must be added when running unit tests through Maven:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>3.0.0-M6</version>
            <configuration>
                    <argLine>--add-opens=java.base/java.nio=ALL-UNNAMED</argLine>
            </configuration>
        </plugin>
    </plugins>
</build>

Or they can be added via environment variable, for example when executing your code:

_JAVA_OPTIONS="--add-opens=java.base/java.nio=ALL-UNNAMED" mvn exec:java -Dexec.mainClass="YourMainCode"

Installing from Source

See Java Development.

IDE Configuration

Generally, no additional configuration should be needed. However, ensure your Maven or other build configuration has the --add-opens flag as described above, so that the IDE picks it up and runs tests with that flag as well.

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