Build a multi-release and provide a module descriptor

.github/workflows/build-and-test.yml

@@ -11,22 +11,23 @@ on:
 
 
 jobs:
-  buildon-linux:
+  build-on-linux:
     strategy:
       matrix:
         os: [ ubuntu-latest ]
-        # New gradle doesn't run on <= 8
-        # Java >= 12 doesn't support source/target level 6 anymore
-        java: [ 8, 9, 10, 11 ]
+        # See CONTRIBUTING.md on JDK 11 build requirement
+        java: [ 11 ]
         architecture: [ x86, x64 ]
+        distribution: [ 'zulu', 'adopt' ]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
       - name: Set up JDK ${{ matrix.java }}
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v2
         with:
           java-version: ${{ matrix.java }}
           architecture: ${{ matrix.architecture }}
+          distribution: ${{ matrix.distribution }}
       - name: Cache Gradle packages
         uses: actions/cache@v2
         with:
@@ -41,19 +42,20 @@ jobs:
     strategy:
       matrix:
         os: [ macos-latest ]
-        # New gradle doesn't run on <= 8
-        # Java >= 12 doesn't support source/target level 6 anymore
-        java: [ 8, 9, 10, 11 ]
+        # See CONTRIBUTING.md on JDK 11 build requirement
+        java: [ 11 ]
         # MacOS has no support for x86 ("Error: No valid download found for version 11.x and package jdk.")
         architecture: [ x64 ]
+        distribution: [ 'zulu', 'adopt' ]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
       - name: Set up JDK ${{ matrix.java }}
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v2
         with:
           java-version: ${{ matrix.java }}
           architecture: ${{ matrix.architecture }}
+          distribution: ${{ matrix.distribution }}
       - name: Cache Gradle packages
         uses: actions/cache@v2
         with:
@@ -68,10 +70,10 @@ jobs:
     strategy:
       matrix:
         os: [ windows-latest ]
-        # New gradle doesn't run on <= 8
-        # Java >= 12 doesn't support source/target level 6 anymore
-        java: [ 8, 9, 10, 11 ]
+        # See CONTRIBUTING.md on JDK 11 build requirement
+        java: [ 11 ]
         architecture: [ x86, x64 ]
+        distribution: [ 'zulu', 'adopt' ]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
@@ -80,6 +82,7 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
           architecture: ${{ matrix.architecture }}
+          distribution: ${{ matrix.distribution }}
       - name: Cache Gradle packages
         uses: actions/cache@v2
         with:

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

@@ -2,20 +2,41 @@ 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
+        exclude('de/**')
+    }
 }
 
 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