ci: using JDK 11+ to compile and JDK 8 to run junit (8) (#1870)

.github/workflows/ci.yaml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [8, 11, 17]
+        java: [11, 17]
     steps:
     - uses: actions/checkout@v3
     - uses: actions/setup-java@v3
@@ -36,14 +36,42 @@ jobs:
     - 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: zulu
+    - run: echo "JAVA8_HOME=${JAVA_HOME}" >> $GITHUB_ENV
+      shell: bash
+    - uses: actions/setup-java@v3
+      with:
+        java-version: 11
+        distribution: zulu
+    - run: echo "JAVA11_HOME=${JAVA_HOME}" >> $GITHUB_ENV
+      shell: bash
+    - run: .kokoro/build.sh
+      env:
+        JOB_TYPE: test
   windows:
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v3
     - uses: actions/setup-java@v3
       with:
-        distribution: zulu
         java-version: 8
+        distribution: zulu
+    - run: echo "JAVA8_HOME=${JAVA_HOME}" >> $GITHUB_ENV
+      shell: bash
+    - uses: actions/setup-java@v3
+      with:
+        java-version: 11
+        distribution: zulu
+    - run: echo "JAVA11_HOME=${JAVA_HOME}" >> $GITHUB_ENV
+      shell: bash
     - run: java -version
     - run: .kokoro/build.bat
       env:

.kokoro/build.sh

@@ -23,6 +23,17 @@ cd ${scriptDir}/..
 # include common functions
 source ${scriptDir}/common.sh
 
+function setJava() {
+  export JAVA_HOME=$1
+  export PATH=${JAVA_HOME}/bin:$PATH
+}
+
+# units-java8 uses both JDK 11 and JDK 8. GraalVM dependencies require JDK 11 to
+# compile the classes touching GraalVM classes.
+if [ ! -z "${JAVA11_HOME}" ]; then
+  setJava "${JAVA11_HOME}"
+fi
+
 # Print out Maven & Java version
 mvn -version
 echo ${JOB_TYPE}
@@ -42,12 +53,19 @@ if [[ ! -z "${GOOGLE_APPLICATION_CREDENTIALS}" && "${GOOGLE_APPLICATION_CREDENTI
     export GOOGLE_APPLICATION_CREDENTIALS=$(realpath ${KOKORO_GFILE_DIR}/${GOOGLE_APPLICATION_CREDENTIALS})
 fi
 
+# units-java8 uses both JDK 11 and JDK 8. We ensure the generated class files
+# are compatible with Java 8 when running tests.
+if [ ! -z "${JAVA8_HOME}" ]; then
+  setJava "${JAVA8_HOME}"
+  mvn -version
+fi
+
 RETURN_CODE=0
 set +e
 
 case ${JOB_TYPE} in
 test)
-    mvn test -B \
+    mvn test -B -V \
       -Dclirr.skip=true \
       -Denforcer.skip=true \
       -Djava.net.preferIPv4Stack=true

.kokoro/release/common.cfg

@@ -9,7 +9,7 @@ build_file: "java-spanner/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
   key: "TRAMPOLINE_IMAGE"
-  value: "gcr.io/cloud-devrel-kokoro-resources/java8"
+  value: "gcr.io/cloud-devrel-kokoro-resources/java11"
 }
 
 before_action {

owlbot.py

@@ -32,6 +32,7 @@
         ".kokoro/presubmit/java8-samples.cfg",
         ".kokoro/presubmit/java11-samples.cfg",
         ".kokoro/presubmit/samples.cfg",
+        ".kokoro/release/common.cfg",
         "samples/install-without-bom/pom.xml",
         "samples/snapshot/pom.xml",
         "samples/snippets/pom.xml",
@@ -40,6 +41,7 @@
         ".github/release-please.yml",
         ".github/blunderbuss.yml",
         ".github/workflows/samples.yaml",
+        ".github/workflows/ci.yaml",
         ".kokoro/build.sh",
     ]
 )

pom.xml

@@ -224,4 +224,17 @@
     </plugins>
   </reporting>
 
+  <profiles>
+    <profile>
+      <!-- JDK 9+ has the "release" option to ensure the generated bytecode is
+       compatible with Java 8. -->
+      <id>compiler-release-8</id>
+      <activation>
+        <jdk>[9,]</jdk>
+      </activation>
+      <properties>
+        <maven.compiler.release>8</maven.compiler.release>
+      </properties>
+    </profile>
+  </profiles>
 </project>