Remove Jvm toolchain from conventions, upgrade Github workflow Jdk to 21

.github/workflows/generate-screenshots.yml

@@ -36,7 +36,7 @@ jobs:
       - uses: actions/setup-java@v3
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
           cache: gradle
 
       - name: Build OPENRNDR

.github/workflows/release-candidate-to-maven-central.yml

@@ -11,7 +11,7 @@ jobs:
       - uses: actions/setup-java@v3
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
       - name: Build ORX
         run: ./gradlew -Prelease.useLastTag=true build
       - name: Decode

.github/workflows/release-to-maven-central.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/setup-java@v3
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
       - name: Build ORX
         run: ./gradlew -Prelease.useLastTag=true build
       - name: Decode

buildSrc/src/main/kotlin/org/openrndr/extra/convention/kotlin-jvm.gradle.kts

@@ -57,9 +57,7 @@ dependencies {
     "demoRuntimeOnly"(libs.slf4j.simple)
 }
 
-kotlin {
+
-    jvmToolchain(libs.versions.jvmTarget.get().toInt())
-}
 
 tasks {
     @Suppress("UNUSED_VARIABLE")
@@ -79,14 +77,19 @@ tasks {
         }
     }
     withType<KotlinCompile>() {
+        kotlinOptions.jvmTarget = libs.versions.jvmTarget.get()
         kotlinOptions.apiVersion = libs.versions.kotlinApi.get()
         kotlinOptions.languageVersion = libs.versions.kotlinLanguage.get()
+        kotlinOptions.freeCompilerArgs += "-Xexpect-actual-classes"
+        kotlinOptions.freeCompilerArgs += "-Xjdk-release=${libs.versions.jvmTarget.get()}"
     }
 }
 
 java {
     withJavadocJar()
     withSourcesJar()
+    targetCompatibility = JavaVersion.valueOf("VERSION_${libs.versions.jvmTarget.get()}")
+    sourceCompatibility = JavaVersion.valueOf("VERSION_${libs.versions.jvmTarget.get()}")
 }
 
 val isReleaseVersion = !(version.toString()).endsWith("SNAPSHOT")

buildSrc/src/main/kotlin/org/openrndr/extra/convention/kotlin-multiplatform.gradle.kts

@@ -4,7 +4,10 @@ import CollectScreenshotsTask
 import org.gradle.accessors.dm.LibrariesForLibs
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.gradle.nativeplatform.platform.internal.DefaultNativePlatform
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.dsl.KotlinCompile
+import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
+
 
 val libs = the<LibrariesForLibs>()
 
@@ -28,14 +31,18 @@ repositories {
 
 group = "org.openrndr.extra"
 
-tasks.withType<KotlinCompile>() {
+tasks.withType<KotlinCompile<*>> {
     kotlinOptions.apiVersion = libs.versions.kotlinApi.get()
     kotlinOptions.languageVersion = libs.versions.kotlinLanguage.get()
+    kotlinOptions.freeCompilerArgs += "-Xexpect-actual-classes"
+    kotlinOptions.freeCompilerArgs += "-Xjdk-release=${libs.versions.jvmTarget.get()}"
+}
+tasks.withType<KotlinJvmCompile>().configureEach {
+    compilerOptions.jvmTarget.set(JvmTarget.fromTarget(libs.versions.jvmTarget.get()))
 }
 
 kotlin {
     jvm {
-        jvmToolchain(libs.versions.jvmTarget.get().toInt())
         compilations {
             val main by getting