diff --git a/build.gradle b/build.gradle
index 88738b9..1747233 100644
--- a/build.gradle
+++ b/build.gradle
@@ -30,9 +30,16 @@ test {
     }
 }
 
+def jvmTargetVersion = "11"
 compileKotlin {
-    kotlinOptions.jvmTarget = "11"
+    kotlinOptions.jvmTarget = jvmTargetVersion
+}
+compileJava {
+    targetCompatibility = jvmTargetVersion
 }
 compileTestKotlin {
-    kotlinOptions.jvmTarget = "11"
+    kotlinOptions.jvmTarget = jvmTargetVersion
+}
+compileTestJava {
+    targetCompatibility = jvmTargetVersion
 }