diff --git a/build.gradle.kts b/build.gradle.kts
index 8063d23..7cbba06 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -68,6 +68,11 @@ sourceSets {
     }
 }
 
+tasks.compileJava {
+    sourceCompatibility = JavaVersion.VERSION_21.toString()
+    targetCompatibility = JavaVersion.VERSION_21.toString()
+}
+
 tasks.compileKotlin {
     kotlinOptions { jvmTarget = "21" }
 }