diff --git a/buildSrc/src/main/kotlin/JvmToolchain.kt b/buildSrc/src/main/kotlin/JvmToolchain.kt
index 94bebc6d99a..735f2ff912c 100644
--- a/buildSrc/src/main/kotlin/JvmToolchain.kt
+++ b/buildSrc/src/main/kotlin/JvmToolchain.kt
@@ -43,6 +43,9 @@ fun Project.shouldOverrideObsoleteJdk(
 fun Project.configureJvmToolchain(
     jdkVersion: JdkMajorVersion
 ) {
+    // Ensure java only modules also set default toolchain
+    configureJavaOnlyToolchain(jdkVersion)
+
     plugins.withId("org.jetbrains.kotlin.jvm") {
         val kotlinExtension = extensions.getByType<KotlinTopLevelExtension>()
 
diff --git a/prepare/compiler/build.gradle.kts b/prepare/compiler/build.gradle.kts
index f8a062af6bd..ea477e4c525 100644
--- a/prepare/compiler/build.gradle.kts
+++ b/prepare/compiler/build.gradle.kts
@@ -11,7 +11,6 @@ plugins {
     java
 }
 
-val JDK_18: String by rootProject.extra
 
 val fatJarContents by configurations.creating {
     isCanBeResolved = true