diff --git a/.github/workflows/reusable-unit-tests.yml b/.github/workflows/reusable-unit-tests.yml
index 34d992c397c2..06a48362c404 100644
--- a/.github/workflows/reusable-unit-tests.yml
+++ b/.github/workflows/reusable-unit-tests.yml
@@ -59,9 +59,15 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: setup jdk${{ inputs.jdk }}
-        run: echo "JAVA_HOME=$JAVA_HOME_${{ inputs.jdk }}_X64" >> $GITHUB_ENV
+      # skip the "cache: maven" step from setup-java. We explicitly use a
+      # different cache key since we cannot reuse it across commits.
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: ${{ inputs.jdk }}
 
+      # the build step produces SNAPSHOT artifacts into the local maven repository,
+      # we include github.sha in the cache key to make it specific to that build/jdk
       - name: Restore Maven repository
         id: maven-restore
         uses: actions/cache/restore@v3
diff --git a/.github/workflows/standard-its.yml b/.github/workflows/standard-its.yml
index 2648dc0993b6..ae78a1f2a836 100644
--- a/.github/workflows/standard-its.yml
+++ b/.github/workflows/standard-its.yml
@@ -153,6 +153,8 @@ jobs:
       - name: Setup java
         run: export JAVA_HOME=$JAVA_HOME_8_X64
 
+      # the build step produces SNAPSHOT artifacts into the local maven repository,
+      # we include github.sha in the cache key to make it specific to that build/jdk
       - name: Restore Maven repository
         id: maven-restore
         uses: actions/cache/restore@v3
diff --git a/.github/workflows/static-checks.yml b/.github/workflows/static-checks.yml
index 4b1c4db0c68d..49cd516f5cae 100644
--- a/.github/workflows/static-checks.yml
+++ b/.github/workflows/static-checks.yml
@@ -41,7 +41,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [ '8', '11', '17' ]
+        java: [ '8', '11', '17', '21' ]
     runs-on: ubuntu-latest
     steps:
       - name: checkout branch
diff --git a/.github/workflows/unit-and-integration-tests-unified.yml b/.github/workflows/unit-and-integration-tests-unified.yml
index 6ff6c8bd6500..d834143695d3 100644
--- a/.github/workflows/unit-and-integration-tests-unified.yml
+++ b/.github/workflows/unit-and-integration-tests-unified.yml
@@ -56,16 +56,21 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        jdk: [ '8', '11', '17' ]
+        jdk: [ '8', '11', '17', '21' ]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout branch
         uses: actions/checkout@v3
 
-      - name: setup jdk${{ matrix.jdk }}
-        run: |
-          echo "JAVA_HOME=$JAVA_HOME_${{ matrix.jdk }}_X64" >> $GITHUB_ENV
+      # skip the "cache: maven" step from setup-java. We explicitly use a
+      # different cache key since we cannot reuse it across commits.
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: ${{ matrix.jdk }}
 
+      # the build step produces SNAPSHOT artifacts into the local maven repository,
+      # we include github.sha in the cache key to make it specific to that build/jdk
       - name: Cache Maven m2 repository
         id: maven
         uses: actions/cache@v3
@@ -112,7 +117,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        jdk: [ 11, 17 ]
+        jdk: [ 11, 17, 21 ]
     name: "unit tests (jdk${{ matrix.jdk }}, sql-compat=true)"
     uses: ./.github/workflows/unit-tests.yml
     needs: unit-tests