Upgraded to Kotlin 1.5.31.

examples/build.gradle.kts

@@ -3,7 +3,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 plugins {
     id("application")
     id("com.github.ben-manes.versions") version "0.39.0"
-    kotlin("jvm") version "1.5.30"
+    kotlin("jvm") version "1.5.31"
 }
 
 // ./gradlew run runJava
@@ -21,6 +21,11 @@ dependencies {
     implementation("net.thauvin.erik:akismet-kotlin:0.9.3-SNAPSHOT")
 }
 
+java {
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
+}
+
 application {
     mainClass.set("com.example.AkismetExampleKt")
 }