build: use JDK 17 or 21 to run Gradle; compile/test with JDK 11, 17, and 21

- on CI build with Java 21, test with 11, 17 and 21
- on Dev machine, build can also be 17
- Decouple JDK to run Gradle from the JDK used to compile/test.
- Use Java toolchains to select JDK 11 for compilation and test
- Set javac --release 11 for consistent API/bytecode.
- Launch Test tasks with the JDK 11 toolchain for non-xtend cases
- Launch test tasks with JDK 17, 21 for all tests
- Update Tycho to newer version that works with Java 21

Co-authored-by: Jonah Graham <[email protected]>

Author: sebthom

.github/workflows/validate.yml

@@ -45,13 +45,15 @@ jobs:
       uses: actions/checkout@v5  # https://github.com/actions/checkout
 
 
-    - name: "Install: JDK 11 ☕"
+    - name: "Install: JDKs for building and testing"
       uses: actions/setup-java@v5  # https://github.com/actions/setup-java
       with:
         distribution: temurin
-        java-version: 11
+        java-version: |
+          11
+          17
+          21
         cache: gradle
 
-
     - name: Build with Gradle 🏗️
-      run: ./gradlew build
+      run: ./gradlew build testOlderJavas

gradle.properties

@@ -0,0 +1,9 @@
+org.gradle.daemon=false
+org.gradle.java.installations.auto-detect=true
+org.gradle.java.installations.auto-download=true
+
+# Optionally, you can hint custom JDK locations (semicolon-separated on Windows):
+# org.gradle.java.installations.paths=C:\\jdks\\jdk-11;C:\\jdks\\jdk-21
+
+# To run Gradle itself on a specific JDK (machine-specific), prefer setting JAVA_HOME
+# before invoking Gradle or use --java-home on the command line.

gradle/java-compiler-settings.gradle

@@ -10,8 +10,32 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  ******************************************************************************/
 
+// Use central version from gradle/versions.gradle
+
+// --- Enforce Java version for running Gradle itself ---
+def currentJava = JavaVersion.current()
+def minJava = JavaVersion.VERSION_17 // xtend requires Java >= 17
+def maxJava = JavaVersion.VERSION_21 // Gradle 9.x is required for Java 25
+
+if (currentJava < minJava || currentJava > maxJava) {
+    throw new GradleException("""
+This build must be run with Java between ${minJava} and ${maxJava}.
+
+Current Java:
+  JavaVersion.current() = ${currentJava}
+  java.version          = ${System.getProperty('java.version')}
+  java.home             = ${System.getProperty('java.home')}
+
+Please switch your JAVA_HOME or use the Gradle wrapper with a compatible JDK.
+
+In addition, to run testOlderJavas tasks Java 17 and Java 11 must be discovrable.
+See https://docs.gradle.org/8.6/userguide/toolchains.html#sec:auto_detection
+""")
+}
+
 java {
-	sourceCompatibility = JavaVersion.VERSION_11
+	sourceCompatibility = JavaVersion.toVersion(versions.java)
+	targetCompatibility = JavaVersion.toVersion(versions.java)
 }
 
 tasks.withType(Javadoc) {
@@ -21,6 +45,8 @@ tasks.withType(Javadoc) {
 
 tasks.withType(JavaCompile) {
 	options.encoding = 'UTF-8'
+	// Ensure cross-compilation targets specified Java version
+    options.release = versions.java as Integer
 }
 
 task sourcesJar(type: Jar, dependsOn: classes) {
@@ -87,3 +113,59 @@ if (findProperty('ignoreTestFailures') == 'true') {
 		ignoreFailures = true
 	}
 }
+
+def testDir = file('src/test/java')
+def xtendTestClassPatterns = []
+
+if (testDir.exists()) {
+	testDir.eachFileRecurse { File f ->
+		if (f.name.endsWith('.xtend')) {
+			// Path relative to src/test/java, with Unix-ish separators
+			def rel = testDir.toPath().relativize(f.toPath()).toString()
+			rel = rel.replace(File.separatorChar, '/' as char)
+
+			// Replace .xtend with .class, wildcard anything before it
+			// e.g. com/foo/BarTest.xtend -> **/com/foo/BarTest.class
+			def classPattern = "**/${rel[0..-6]}class"
+			xtendTestClassPatterns << classPattern
+		}
+	}
+}
+
+tasks.register('testJava11', Test) {
+	description = 'Runs non-xtend tests on Java 11 JVM'
+	group = 'verification'
+
+	testClassesDirs = sourceSets.test.output.classesDirs
+	classpath = sourceSets.test.runtimeClasspath
+
+	// Current version of xtend require JVM >= 17 to run, 
+	// so exclude xtend based tests
+	if (!xtendTestClassPatterns.isEmpty()) {
+		exclude xtendTestClassPatterns
+	}
+
+	javaLauncher.set(
+		javaToolchains.launcherFor {
+			languageVersion = JavaLanguageVersion.of(11)
+		}
+	)
+}
+
+tasks.register('testJava17', Test) {
+	description = 'Runs tests on Java 17 JVM'
+	group = 'verification'
+
+	testClassesDirs = sourceSets.test.output.classesDirs
+	classpath = sourceSets.test.runtimeClasspath
+
+	javaLauncher.set(
+		javaToolchains.launcherFor {
+			languageVersion = JavaLanguageVersion.of(17)
+		}
+	)
+}
+
+tasks.register('testOlderJavas') {
+	dependsOn tasks.named('testJava17'), tasks.named('testJava11')
+}

gradle/manifest-gen.gradle

@@ -21,7 +21,7 @@ def qualifiedVersion = baseVersion + '.v' + buildTime
 jar.bundle.bnd (
 	'Bundle-Version': qualifiedVersion,
 	'Bundle-Vendor': 'Eclipse LSP4J',
-	'Bundle-RequiredExecutionEnvironment': 'JavaSE-11',
+	'Bundle-RequiredExecutionEnvironment': "JavaSE-${versions.java}",
 	"-exportcontents": "org.eclipse.lsp4j.*",
 	"-savemanifest": "build/tmp/bnd/MANIFEST.MF",
 )

gradle/versions.gradle

@@ -14,6 +14,9 @@ version = '1.0.0-SNAPSHOT'
 
 ext.versions = [
 	'xtend_lib': '2.32.0',
+	// Additional JDK version configuration is in java-compiler-settings
+	'java': '11',
+
 	'guava': '[32.1.2,34)',
 	'gson': '[2.9.1,3.0)',
 

org.eclipse.lsp4j/build.gradle

@@ -1,23 +1,18 @@
 /******************************************************************************
  * Copyright (c) 2016 TypeFox and others.
- * 
+ *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0,
  * or the Eclipse Distribution License v. 1.0 which is available at
  * http://www.eclipse.org/org/documents/edl-v10.php.
- * 
+ *
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  ******************************************************************************/
 
 ext.title = 'LSP4J'
 description = 'Java bindings for the Language Server Protocol'
 
-java {
-	sourceCompatibility = JavaVersion.VERSION_11
-	targetCompatibility = JavaVersion.VERSION_11
-}
-
 dependencies {
 	compileOnly project(":org.eclipse.lsp4j.generator")
 	api project(":org.eclipse.lsp4j.jsonrpc")

releng/build.Jenkinsfile

@@ -7,7 +7,9 @@ pipeline {
   }
   tools {
     maven 'apache-maven-latest'
-    jdk 'temurin-jdk11-latest'
+    // Default JDK picked up from here, build and test requires
+    // older JDKs too, which are discovered by gradle from ~/.m2/toolchains.xml
+    jdk 'temurin-jdk21-latest'
   }
   options {
     timestamps()
@@ -32,12 +34,13 @@ pipeline {
           sh "echo $JAVA_HOME"
           sh "java -version"
           sh "which java"
+          sh "cat ~/.m2/toolchains.xml"
           sh "./gradlew \
                 --no-daemon \
                 -PignoreTestFailures=true \
                 --refresh-dependencies \
                 --continue \
-                clean build signJar publish \
+                clean build testOlderJavas signJar publish \
                 "
         }
       }
@@ -81,8 +84,8 @@ pipeline {
   }
   post {
     always {
-      junit '**/build/test-results/test/*.xml'
-      archiveArtifacts 'build/**'
+      junit '**/build/test-results/**/*.xml'
+      archiveArtifacts 'build/**,**/build/reports/'
     }
     cleanup {
       script {

releng/pom.xml

@@ -8,7 +8,7 @@
 	<packaging>pom</packaging>
 
 	<properties>
-		<tycho-version>2.7.5</tycho-version>
+		<tycho-version>5.0.0</tycho-version>
 		<root-dir>${maven.multiModuleProjectDirectory}/..</root-dir>
 	</properties>