chore: use javac -release and kotlinc -Xjdk-release

The change ensures the generated bytecode adheres to the APIs for the target Java release.

Previously, only sourceCompatibility and targetCompatibility were used,
and they might cause issues like NoSuchMethodError when a newer javac compiles
with -target older_release.

Note: it is good to use a new an up to date javac to avoid issues in the compiler itself,
so having a proper `-release ..` configuration is vital.

See https://www.morling.dev/blog/bytebuffer-and-the-dreaded-nosuchmethoderror/

Author: vlsi

buildSrc/build.gradle.kts

@@ -35,16 +35,18 @@ dependencies {
 }
 
 java {
-  sourceCompatibility = JavaVersion.toVersion(toolchainVersion)
-  targetCompatibility = JavaVersion.toVersion(toolchainVersion)
-
   toolchain {
     languageVersion = JavaLanguageVersion.of(toolchainVersion)
     vendor = JvmVendorSpec.ADOPTIUM
   }
 }
 
+tasks.withType<JavaCompile>().configureEach { options.release = toolchainVersion }
+
 kotlin {
   jvmToolchain(toolchainVersion)
-  compilerOptions { jvmTarget = JvmTarget.fromTarget(toolchainVersion.toString()) }
+  compilerOptions {
+    jvmTarget = JvmTarget.fromTarget(toolchainVersion.toString())
+    freeCompilerArgs.add("-Xjdk-release=$toolchainVersion")
+  }
 }

buildSrc/src/main/kotlin/pklAllProjects.gradle.kts

@@ -16,7 +16,7 @@
 import com.diffplug.gradle.spotless.KotlinGradleExtension
 import org.gradle.accessors.dm.LibrariesForLibs
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
 
 plugins { id("com.diffplug.spotless") }
 
@@ -52,15 +52,14 @@ configurations.all {
 }
 
 plugins.withType(JavaPlugin::class).configureEach {
-  val java = project.extensions.getByType<JavaPluginExtension>()
-  java.sourceCompatibility = JavaVersion.VERSION_17
-  java.targetCompatibility = JavaVersion.VERSION_17
+  tasks.withType<JavaCompile>().configureEach { options.release = 17 }
 }
 
-tasks.withType<KotlinCompile>().configureEach {
+tasks.withType<KotlinJvmCompile>().configureEach {
   compilerOptions {
     jvmTarget = JvmTarget.JVM_17
     freeCompilerArgs.addAll("-Xjsr305=strict", "-Xjvm-default=all")
+    freeCompilerArgs.add("-Xjdk-release=17")
   }
 }
 

buildSrc/src/main/kotlin/pklJavaLibrary.gradle.kts

@@ -34,14 +34,9 @@ val libs = the<LibrariesForLibs>()
 val info = project.extensions.getByType<BuildInfo>()
 
 java {
-  val jvmTarget = JavaVersion.toVersion(info.jvmTarget)
-
   withSourcesJar() // creates `sourcesJar` task
   withJavadocJar()
 
-  sourceCompatibility = jvmTarget
-  targetCompatibility = jvmTarget
-
   toolchain {
     languageVersion = info.jdkToolchainVersion
     vendor = info.jdkVendor
@@ -112,10 +107,8 @@ tasks.compileJava {
 }
 
 tasks.withType<JavaCompile>().configureEach {
-  val jvmTarget = JavaVersion.toVersion(info.jvmTarget)
   javaCompiler = info.javaCompiler
-  sourceCompatibility = jvmTarget.majorVersion
-  targetCompatibility = jvmTarget.majorVersion
+  options.release = info.jvmTarget
 }
 
 tasks.withType<JavaExec>().configureEach { jvmArgs(info.jpmsAddModulesFlags) }

buildSrc/src/main/kotlin/pklKotlinLibrary.gradle.kts

@@ -42,5 +42,8 @@ tasks.compileKotlin {
 }
 
 tasks.withType<KotlinJvmCompile>().configureEach {
-  compilerOptions { jvmTarget = JvmTarget.fromTarget(buildInfo.jvmTarget.toString()) }
+  compilerOptions {
+    jvmTarget = JvmTarget.fromTarget(buildInfo.jvmTarget.toString())
+    freeCompilerArgs.addAll("-Xjdk-release=${buildInfo.jvmTarget}")
+  }
 }