Build a multi-release jar to provide module-info for JDK 11

CONTRIBUTING.md

@@ -1,4 +1,7 @@
 # Contributing
 
 Feel free to fork the project and create pull requests. Please use the `develop` branch for new features,
-I like to keep the `master` branch stable.
+I like to keep the `master` branch stable.
+
+Note that JDK 11 is required to build. Older versions do not allow creating a Multi-Release JAR and 
+newer versions do not support `--release 6`.

argon2-jvm-nolibs/build.gradle

@@ -2,18 +2,38 @@ plugins {
     id 'org.sonarqube' version '3.0'
 }
 
+sourceSets {
+    java11 {
+        java {
+            srcDirs = ['src/main/java', 'src/main/java11']
+        }
+    }
+}
+
 jar {
     manifest {
         attributes(
-                'Automatic-Module-Name': 'de.mkammerer.argon2.nolibs'
+                'Automatic-Module-Name': 'de.mkammerer.argon2.nolibs',
+                'Multi-Release': 'true'
         )
     }
+    into('META-INF/versions/11') {
+        from sourceSets.java11.output
+    }
 }
 
 dependencies {
     implementation 'net.java.dev.jna:jna:5.8.0'
 }
 
+compileJava11Java {
+    sourceCompatibility = 11
+    targetCompatibility = 11
+    options.compilerArgs.addAll([
+            '--release', '11',
+            '--module-path', sourceSets.main.compileClasspath.asPath]);
+}
+
 sonarqube {
     properties {
         property 'sonar.exclusions', 'src/main/java/de/mkammerer/argon2/jna/*.java'

argon2-jvm-nolibs/src/main/java11/module-info.java

@@ -0,0 +1,5 @@
+module de.mkammerer.argon2.nolibs {
+    exports de.mkammerer.argon2;
+    exports de.mkammerer.argon2.jna;
+    requires com.sun.jna;
+}

build.gradle

@@ -15,6 +15,10 @@ subprojects {
         options.encoding = 'UTF-8'
     }
 
+    compileJava {
+        options.compilerArgs.addAll(['--release', '6']);
+    }
+
     java {
         sourceCompatibility = JavaVersion.VERSION_1_6
         targetCompatibility = JavaVersion.VERSION_1_6