Windows Native Access

On Windows, Æsh Readline needs access to the Windows Console API (Kernel32) for raw terminal input, console mode control, and terminal size detection. The terminal-tty module ships as a multi-release JAR with two implementations:

On Java 22+, the Foreign Function & Memory API calls Kernel32 directly from pure Java – no DLL, no native compilation, no cross-compiler toolchain.

Runtime Requirements

Java 22+

Applications running on Java 22+ must enable native access for the FFM API:

java --enable-native-access=ALL-UNNAMED -jar myapp.jar

Without this flag, Java 22-23 prints a warning and Java 24+ throws an IllegalCallerException.

Java 23+

Starting with Java 23, the JVM also warns when JNI loads native libraries without --enable-native-access. This means the flag is required on Java 23+ regardless of which implementation is active. The FFM path is the better choice here since it eliminates the DLL entirely.

Java 8 – 22

No special flags are needed. The JNI implementation loads aesh-console.dll from the JAR automatically.

How It Works

The multi-release JAR contains two versions of WinConsoleNative:

terminal-tty.jar
├── org/aesh/terminal/tty/impl/WinConsoleNative.class          (JNI, Java 8)
├── META-INF/versions/22/org/aesh/terminal/tty/impl/WinConsoleNative.class  (FFM, Java 22+)
├── META-INF/MANIFEST.MF                                        (Multi-Release: true)
└── native/windows-x86_64/aesh-console.dll                      (for JNI fallback)

The JVM automatically selects the correct class based on the runtime version. No configuration or code changes are needed – callers like WinSysTerminal and AbstractWindowsTerminal use the same API regardless of which implementation is active.

Both implementations wrap these Windows Console API functions:

Building from Source

The multi-release JAR is built automatically based on the JDK used:

With Java 22+ – produces a multi-release JAR with both JNI and FFM variants:

export JAVA_HOME=/path/to/jdk-24
mvn clean package

With Java 8-21 – produces a standard JAR with only the JNI variant:

export JAVA_HOME=/path/to/jdk-21
mvn clean package

For releases, build with Java 22+ to include the FFM implementation.

GraalVM Native Image

The FFM implementation is compatible with GraalVM native-image (25+). For GraalVM 23-24, use the JNI implementation – the resource-config.json in the JAR ensures the DLL is included in native images.

Maven Configuration for Downstream Projects

If your project uses maven-surefire-plugin or maven-exec-plugin and runs on Java 22+, add the native access flag:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <argLine>--enable-native-access=ALL-UNNAMED</argLine>
    </configuration>
</plugin>

To avoid breaking builds on older JDKs, use a profile:

<profile>
    <id>java22-native-access</id>
    <activation>
        <jdk>[22,)</jdk>
    </activation>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <argLine>--enable-native-access=ALL-UNNAMED</argLine>
                </configuration>
            </plugin>
        </plugins>
    </build>
</profile>

Cygwin and MSYS2

When running under Cygwin or MSYS2, Æsh Readline detects the POSIX-compatible environment and uses PTY-based terminal access instead of the Windows Console API. Neither JNI nor FFM is used in this case.