diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e3bb26e37..29d078511 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,23 +1,8 @@
-# Copyright 2022 Google LLC
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-# Github action job to test core java library features on
-# downstream client libraries before they are released.
-on:
+'on':
   push:
     branches:
-    - main
-  pull_request:
+      - 2.27.x
+  pull_request: null
 name: ci
 jobs:
   units:
@@ -25,65 +10,101 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [8, 11, 17]
+        java:
+          - 11
+          - 17
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-java@v3
-      with:
-        distribution: zulu
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: test
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: test
+  units-java8:
+    name: units (8)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          java-version: 8
+          distribution: temurin
+      - name: >-
+          Set jvm system property environment variable for surefire plugin (unit
+          tests)
+        run: echo "SUREFIRE_JVM_OPT=-Djvm=${JAVA_HOME}/bin/java" >> $GITHUB_ENV
+        shell: bash
+      - uses: actions/setup-java@v3
+        with:
+          java-version: 17
+          distribution: temurin
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: test
   windows:
     runs-on: windows-latest
     steps:
-    - name: Support longpaths
-      run: git config --system core.longpaths true
-    - uses: actions/checkout@v3
-    - uses: actions/setup-java@v3
-      with:
-        distribution: zulu
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/build.bat
-      env:
-        JOB_TYPE: test
+      - name: Support longpaths
+        run: git config --system core.longpaths true
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/build.bat
+        env:
+          JOB_TYPE: test
   dependencies:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [8, 11, 17]
+        java:
+          - 17
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/dependencies.sh
+  javadoc:
+    runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-java@v3
-      with:
-        distribution: zulu
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/dependencies.sh
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 17
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: javadoc
   lint:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-java@v3
-      with:
-        distribution: zulu
-        java-version: 11
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: lint
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 11
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: lint
   clirr:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-java@v3
-      with:
-        distribution: zulu
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: clirr
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: clirr