Add Java 9+ module support (JPMS) for jlink compatibility

README.md

@@ -225,6 +225,51 @@ on the current release):
 ```
 
 
+### Java 9+ Module Support (JPMS)
+---------
+
+wolfCrypt JNI/JCE supports the Java Platform Module System (JPMS) introduced
+in Java 9. This enables use with `jlink` for creating custom, minimal Java
+runtimes.
+
+**Module Information:**
+
+- Module name: `com.wolfssl.wolfcrypt`
+- Exported packages: `com.wolfssl.wolfcrypt`, `com.wolfssl.provider.jce`
+- Service provider: `java.security.Provider` (WolfCryptProvider)
+
+**Conditional Compilation:**
+
+The `module-info.java` is conditionally compiled based on the JDK version used
+to build:
+
+| JDK Used to Build | Resulting JAR |
+|-------------------|---------------|
+| Java 8 | Standard JAR (no module-info.class) |
+| Java 9+ | Modular JAR (includes module-info.class) |
+
+When building with Java 8, the `module-info.java` is automatically excluded
+from compilation, and the resulting JAR works as a standard classpath JAR.
+
+**Using with jlink:**
+
+When built with Java 9+, the wolfCrypt JNI/JCE JAR can be used with `jlink` to
+create a custom Java runtime that includes the wolfCrypt module:
+
+```
+$ jlink \
+    --module-path lib/wolfcrypt-jni.jar:$JAVA_HOME/jmods \
+    --add-modules com.wolfssl.wolfcrypt \
+    --output custom-runtime \
+    --no-header-files \
+    --no-man-pages
+
+$ ./custom-runtime/bin/java --list-modules
+```
+
+**Note:** The native wolfCrypt JNI shared library (`libwolfcryptjni.so/dylib`)
+must still be available on the native library path at runtime.
+
 ### Example / Test Code
 ---------
 

build.xml

@@ -23,6 +23,7 @@
 
     <!-- set properties for this build -->
     <property name="src.dir" value="src/main/java/" />
+    <property name="src.java9.dir" value="src/java9/" />
     <property name="jni.dir" value="jni/include/" />
     <property name="lib.dir" value="lib/" />
     <property name="build.dir" value="build" />
@@ -48,6 +49,18 @@
 
     <property environment="env" />
 
+    <!-- Detect Java 9+ for module-info.java compilation -->
+    <condition property="isJava9Plus">
+        <not>
+            <or>
+                <equals arg1="${ant.java.version}" arg2="1.5"/>
+                <equals arg1="${ant.java.version}" arg2="1.6"/>
+                <equals arg1="${ant.java.version}" arg2="1.7"/>
+                <equals arg1="${ant.java.version}" arg2="1.8"/>
+            </or>
+        </not>
+    </condition>
+
     <!-- Detect if running on Windows host -->
     <condition property="isWindows">
         <os family="windows" />
@@ -161,8 +174,24 @@
         </copy>
     </target>
 
+    <!-- Compile module-info.java for Java 9+ module support.
+         Only runs when building with Java 9 or later. When building with
+         Java 8 or earlier, this target is skipped and the resulting JAR
+         will be a standard (non-modular) JAR file. -->
+    <target name="compile-module-info" if="isJava9Plus"
+            description="Compile module-info.java for Java 9+ (skipped on Java 8)">
+        <javac srcdir="${src.java9.dir}"
+               destdir="${build.dir}"
+               release="9"
+               modulepath="${build.dir}"
+               includeantruntime="false">
+            <include name="module-info.java"/>
+        </javac>
+        <echo message="Compiled module-info.java for Java 9+ module support"/>
+    </target>
+
     <!-- create JAR with ONLY JNI classes, not to be used with JCE -->
-    <target name="jar-jni" depends="compile-nativeheaderdir, compile-javah">
+    <target name="jar-jni" depends="compile-nativeheaderdir, compile-javah, compile-module-info">
         <jar jarfile="${lib.dir}/wolfcrypt-jni.jar">
             <manifest>
                 <attribute name="Implementation-Title"
@@ -174,12 +203,13 @@
             </manifest>
             <fileset dir="${build.dir}">
                 <include name="com/wolfssl/wolfcrypt/*.class"/>
+                <include name="module-info.class"/>
             </fileset>
         </jar>
     </target>
 
     <!-- create JAR with JNI and JCE classes, use this when wanting JCE -->
-    <target name="jar-jce" depends="compile-nativeheaderdir, compile-javah">
+    <target name="jar-jce" depends="compile-nativeheaderdir, compile-javah, compile-module-info">
         <jar jarfile="${lib.dir}/wolfcrypt-jni.jar" basedir="${build.dir}">
             <manifest>
                 <attribute name="Implementation-Title"

pom.xml

@@ -69,4 +69,42 @@
             </plugin>
 		</plugins>
 	</build>
+
+    <!-- Profile for Java 9+ module support.
+         Automatically activates when building with JDK 9 or later.
+         Compiles module-info.java and includes it in the JAR. -->
+    <profiles>
+        <profile>
+            <id>java9-module</id>
+            <activation>
+                <jdk>[9,)</jdk>
+            </activation>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-compiler-plugin</artifactId>
+                        <version>3.11.0</version>
+                        <executions>
+                            <!-- Compile module-info.java with Java 9 release -->
+                            <execution>
+                                <id>compile-module-info</id>
+                                <phase>compile</phase>
+                                <goals>
+                                    <goal>compile</goal>
+                                </goals>
+                                <configuration>
+                                    <release>9</release>
+                                    <compileSourceRoots>
+                                        <compileSourceRoot>${project.basedir}/src/java9</compileSourceRoot>
+                                    </compileSourceRoots>
+                                    <multiReleaseOutput>false</multiReleaseOutput>
+                                </configuration>
+                            </execution>
+                        </executions>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
 </project>

src/java9/module-info.java

@@ -0,0 +1,45 @@
+/* module-info.java
+ *
+ * Copyright (C) 2006-2025 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/**
+ * wolfCrypt JNI/JCE Module
+ *
+ * This module provides:
+ * - JNI bindings to the native wolfCrypt cryptography library
+ *   (com.wolfssl.wolfcrypt)
+ * - A JCE provider implementation (com.wolfssl.provider.jce)
+ *
+ * Note: This module-info.java is only compiled when building with Java 9+.
+ * When building with Java 8, this file is excluded and the resulting JAR
+ * will be a standard (non-modular) JAR that works on the classpath.
+ */
+module com.wolfssl.wolfcrypt {
+    /* Required modules */
+    requires java.logging;
+
+    /* Export public API packages */
+    exports com.wolfssl.wolfcrypt;
+    exports com.wolfssl.provider.jce;
+
+    /* Register wolfJCE as a security provider */
+    provides java.security.Provider
+        with com.wolfssl.provider.jce.WolfCryptProvider;
+}