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. Starting with version 3.6, 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.