build: Add support for Java 16

This pull request adds support for building OpenDC using Java 16. 

To make this possible, we have upgraded the following dependencies:
- Kotlin from 1.4.3 to 1.5.0
- Jacoco from 0.8.6 to 0.8.7
- Gradle from 7.0 to 7.0.2

3 files changed, 12 insertions, 34 deletions

diff --git a/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts b/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts
index 3e8aa741..1ea5de4c 100644
--- a/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts
+++ b/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts
@@ -1,3 +1,5 @@
+import gradle.kotlin.dsl.accessors._a850a9ab866951e91ee43960bbc39582.jacoco
+
 /*
  * MIT License
  *
@@ -32,6 +34,11 @@ repositories {
     mavenCentral()
 }
 
+jacoco {
+    // Necessary for Kotlin 1.5.0. See https://github.com/jacoco/jacoco/issues/1155
+    toolVersion = "0.8.7"
+}
+
 tasks.register<JacocoReport>("codeCoverageReport") {
     group = "Coverage reports"
     description = "Generates an aggregate report based on all subprojects"
diff --git a/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts b/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts
index d0534d4f..5c7aea83 100644
--- a/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts
+++ b/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts
@@ -25,41 +25,13 @@ plugins {
     jacoco
 }
 
+jacoco {
+    // Necessary for Kotlin 1.5.0. See https://github.com/jacoco/jacoco/issues/1155
+    toolVersion = "0.8.7"
+}
+
 tasks.jacocoTestReport {
     reports {
         html.isEnabled = true
     }
 }
-
-/* Share sources folder with other projects for aggregated JaCoCo reports */
-configurations.create("transitiveSourcesElements") {
-    isVisible = false
-    isCanBeResolved = false
-    isCanBeConsumed = true
-    extendsFrom(configurations.implementation.get())
-    attributes {
-        attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
-        attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.DOCUMENTATION))
-        attribute(DocsType.DOCS_TYPE_ATTRIBUTE, objects.named("source-folders"))
-    }
-    sourceSets.main.get().java.srcDirs.forEach {
-        outgoing.artifact(it)
-    }
-}
-
-/* Share the coverage data to be aggregated for the whole product */
-configurations.create("coverageDataElements") {
-    isVisible = false
-    isCanBeResolved = false
-    isCanBeConsumed = true
-    extendsFrom(configurations.implementation.get())
-    attributes {
-        attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
-        attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.DOCUMENTATION))
-        attribute(DocsType.DOCS_TYPE_ATTRIBUTE, objects.named("jacoco-coverage-data"))
-    }
-    // This will cause the test task to run if the coverage data is requested by the aggregation task
-    outgoing.artifact(tasks.test.map { task ->
-        task.extensions.getByType<JacocoTaskExtension>().destinationFile!!
-    })
-}
diff --git a/buildSrc/src/main/kotlin/kotlin-conventions.gradle.kts b/buildSrc/src/main/kotlin/kotlin-conventions.gradle.kts
index 703e9938..7fda64a2 100644
--- a/buildSrc/src/main/kotlin/kotlin-conventions.gradle.kts
+++ b/buildSrc/src/main/kotlin/kotlin-conventions.gradle.kts
@@ -39,6 +39,5 @@ java {
 
 tasks.withType<KotlinCompile>().configureEach {
     kotlinOptions.jvmTarget = Libs.jvmTarget.toString()
-    kotlinOptions.useIR = true
     kotlinOptions.freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
 }