Explicitly specify the JVM version (#98)

By default, setup-gradle action uses Java 17. But we need to compile our
plugins with Java 11 for now.

Also, this PR adds parameters to always compile the classes for Java 11
(no matter which Jvm is used - 11 or above)

Author: OptimumCode

Diff for: .github/workflows/build-and-test.yml

@@ -11,11 +11,15 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
-      - name: Validate Gradle Wrapper
-        uses: gradle/actions/wrapper-validation@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 11
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
          gradle-version: wrapper
+         validate-wrappers: 'true'
       - name: Run build with Gradle
         run: ./gradlew clean build --info

Diff for: .github/workflows/publish-gradle-plugin.yml

@@ -38,12 +38,16 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
-      - name: Validate Gradle Wrapper
-        uses: gradle/actions/wrapper-validation@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 11
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
           gradle-version: wrapper
+          validate-wrappers: 'true'
       - name: Publish plugins to Gradle portal
         run: >
           ./gradlew clean build publishPlugins --info
@@ -55,12 +59,16 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
-      - name: Validate Gradle Wrapper
-        uses: gradle/actions/wrapper-validation@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 11
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
           gradle-version: wrapper
+          validate-wrappers: 'true'
       - name: Publish plugins to Gradle portal
         run: >
           ./gradlew clean build publishToSonatype closeAndReleaseStagingRepositories --info

Diff for: .github/workflows/verify-publish-configuration.yml

@@ -13,12 +13,16 @@ jobs:
     steps:
       - name: Checkout project sources
         uses: actions/checkout@v4
-      - name: Validate Gradle Wrapper
-        uses: gradle/actions/wrapper-validation@v4
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 11
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
         with:
           gradle-version: wrapper
+          validate-wrappers: 'true'
       - name: Validate Gradle portal publication configuration
         run: >
           ./gradlew clean publishPlugins --info --validate-only

Diff for: plugin/build.gradle.kts

@@ -1,3 +1,4 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 import org.jetbrains.kotlin.util.capitalizeDecapitalize.capitalizeAsciiOnly
 import org.jlleitschuh.gradle.ktlint.reporter.ReporterType
 
@@ -13,6 +14,18 @@ plugins {
     alias(libs.plugins.gradle.functional.test)
 }
 
+java {
+    targetCompatibility = JavaVersion.VERSION_11
+    sourceCompatibility = JavaVersion.VERSION_11
+}
+
+kotlin {
+    compilerOptions {
+        jvmTarget = JvmTarget.JVM_11
+        freeCompilerArgs.add("-Xjdk-release=11")
+    }
+}
+
 repositories {
     mavenCentral()
     gradlePluginPortal()