[Java] Add Java 16-ea to the build matrix.

Author: vyazelenko

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [ '8', '11', '15' ]
+        java: [ '8', '11', '15', '16-ea' ]
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
@@ -39,8 +39,17 @@ jobs:
         uses: actions/setup-java@v1
         with:
           java-version: ${{ matrix.java }}
+      - name: Setup BUILD_JAVA_HOME
+        if: runner.os == 'Linux'
+        run: echo "BUILD_JAVA_HOME=${JAVA_HOME}" >> $GITHUB_ENV
+      - name: Setup java 8 to run the Gradle script
+        uses: actions/setup-java@v1
+        with:
+          java-version: 8
       - name: Build with Gradle
         run: ./gradlew
+        env:
+          BUILD_JAVA_VERSION: ${{ matrix.java }}
 
   csharp-build:
     name: C# ${{ matrix.dotnet }}

build.gradle

@@ -28,6 +28,25 @@ plugins {
 
 defaultTasks 'clean', 'build'
 
+static def getBuildJavaVersion()
+{
+    def buildJavaVersion = System.getenv('BUILD_JAVA_VERSION') ?: JavaVersion.current().getMajorVersion()
+    if (buildJavaVersion.indexOf('.') > 0)
+    {
+        buildJavaVersion = buildJavaVersion.substring(0, buildJavaVersion.indexOf('.'))
+    }
+    if (buildJavaVersion.indexOf('-') > 0)
+    {
+        buildJavaVersion = buildJavaVersion.substring(0, buildJavaVersion.indexOf('-'))
+    }
+    Integer.parseInt(buildJavaVersion)
+}
+int buildJavaVersion = getBuildJavaVersion()
+
+def javaLauncher = javaToolchains.launcherFor {
+    languageVersion = JavaLanguageVersion.of(buildJavaVersion)
+}
+
 def checkstyleVersion = '8.37'
 def hamcrestVersion = '2.2'
 def mockitoVersion = '3.6.0'
@@ -130,6 +149,10 @@ allprojects {
             failOnVersionConflict()
         }
     }
+
+    tasks.withType(JavaExec).configureEach {
+        executable = javaLauncher.get().executablePath
+    }
 }
 
 jar.enabled = false
@@ -142,6 +165,12 @@ subprojects {
     group = sbeGroup
     version = sbeVersion
 
+    java {
+        toolchain {
+            languageVersion = JavaLanguageVersion.of(buildJavaVersion)
+        }
+    }
+
     checkstyle.toolVersion = "${checkstyleVersion}"
 
     tasks.withType(Sign) {
@@ -156,7 +185,7 @@ subprojects {
     }
 
     tasks.withType(JavaCompile) {
-        if (JavaVersion.current().isJava9Compatible()) {
+        if (buildJavaVersion >= 9) {
             options.compilerArgs.addAll(['--add-exports', 'java.base/java.lang.reflect=ALL-UNNAMED'])
             options.compilerArgs.addAll(['--add-exports', 'jdk.unsupported/sun.misc=ALL-UNNAMED'])
         }
@@ -172,18 +201,20 @@ subprojects {
         options.docEncoding = 'UTF-8'
         options.charSet = 'UTF-8'
         options.links("https://www.javadoc.io/doc/org.agrona/agrona/${agronaVersion}/")
-        if (JavaVersion.current().isJava11Compatible()) {
-            options.links("https://docs.oracle.com/en/java/javase/${JavaVersion.current().majorVersion}/docs/api/")
+        if (buildJavaVersion >= 16) { // Work around for early access versions for which no JavaDoc is published
+            options.links("https://docs.oracle.com/en/java/javase/15/docs/api/")
+        } else if (buildJavaVersion >= 11) {
+            options.links("https://docs.oracle.com/en/java/javase/${buildJavaVersion}/docs/api/")
         } else {
-            options.links("https://docs.oracle.com/javase/${JavaVersion.current().majorVersion}/docs/api/")
+            options.links("https://docs.oracle.com/javase/${buildJavaVersion}/docs/api/")
         }
-        if (JavaVersion.current().isJava10Compatible()) {
+        if (buildJavaVersion >= 10) {
             options.addBooleanOption 'html5', true
         }
     }
 
     test {
-        if (JavaVersion.current().isJava9Compatible()) {
+        if (buildJavaVersion >= 9) {
             jvmArgs('--add-opens', 'java.base/java.lang.reflect=ALL-UNNAMED')
             jvmArgs('--add-exports', 'jdk.unsupported/sun.misc=ALL-UNNAMED')
         }

gradle.properties

@@ -1,4 +1,5 @@
-org.gradle.daemon=true
+org.gradle.java.installations.auto-download=false
+org.gradle.java.installations.fromEnv=BUILD_JAVA_HOME
 
 # HTTP timeouts for Gradle
 systemProp.org.gradle.internal.http.connectionTimeout=300000