diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f7829a8..d7f619d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,10 +13,11 @@ jobs:
       - uses: actions/checkout@v3
         with:
           fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of analysis
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v3
         with:
-          java-version: 17
+          # Matches Jenkinsfile:deployJdk
+          java-version: 21
           distribution: 'oracle'
       - name: Setup Maven
         uses: stCarolas/setup-maven@v.4.5
diff --git a/Jenkinsfile b/Jenkinsfile
index 669b759..f3d3489 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -134,6 +134,7 @@ def upstreamProjects = [
 
 // JDK versions
 if (!binding.hasVariable('deployJdk')) {
+  // Matches build.yml:java-version
   binding.setVariable('deployJdk', '21')
 }
 if (!binding.hasVariable('buildJdks')) {
diff --git a/book/Jenkinsfile b/book/Jenkinsfile
index 93fa014..633e234 100644
--- a/book/Jenkinsfile
+++ b/book/Jenkinsfile
@@ -153,6 +153,7 @@ def upstreamProjects = [
 
 // JDK versions
 if (!binding.hasVariable('deployJdk')) {
+  // Matches build.yml:java-version
   binding.setVariable('deployJdk', '21')
 }
 if (!binding.hasVariable('buildJdks')) {