diff --git a/.github/workflows/build-kdoc.yml b/.github/workflows/build-kdoc.yml
index 8dcfd61..60365e5 100644
--- a/.github/workflows/build-kdoc.yml
+++ b/.github/workflows/build-kdoc.yml
@@ -18,7 +18,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: temurin
-          java-version: 21
+          java-version: 21   # keep in sync with gradle/gradle-daemon-jvm.properties
           cache: gradle
       - uses: gradle/actions/setup-gradle@v6
 
diff --git a/.github/workflows/test-dev.yml b/.github/workflows/test-dev.yml
index 1c50a8d..d6afbf4 100644
--- a/.github/workflows/test-dev.yml
+++ b/.github/workflows/test-dev.yml
@@ -13,7 +13,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: temurin
-          java-version: 21
+          java-version: 21   # keep in sync with gradle/gradle-daemon-jvm.properties
           cache: gradle
       - uses: gradle/actions/setup-gradle@v6
 
@@ -28,7 +28,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: temurin
-          java-version: 21
+          java-version: 21   # keep in sync with gradle/gradle-daemon-jvm.properties
           cache: gradle
       - uses: gradle/actions/setup-gradle@v6
 
diff --git a/gradle/gradle-daemon-jvm.properties b/gradle/gradle-daemon-jvm.properties
new file mode 100644
index 0000000..0b57590
--- /dev/null
+++ b/gradle/gradle-daemon-jvm.properties
@@ -0,0 +1,4 @@
+#
+# https://docs.gradle.org/current/userguide/gradle_daemon.html#sec:configuring_daemon_jvm
+#
+toolchainVersion=21
diff --git a/jitpack.yml b/jitpack.yml
index 40331e0..7883572 100644
--- a/jitpack.yml
+++ b/jitpack.yml
@@ -1,5 +1,5 @@
 jdk:
-  - openjdk21
+  - openjdk21   # keep in sync with gradle/gradle-daemon-jvm.properties
 before_install:
   - sdk install java 21.0.2-open
   - sdk use java 21.0.2-open
\ No newline at end of file