Create build_jar.yml

.github/workflows/build_jar.yml

@@ -0,0 +1,26 @@
+# This workflow will build the extension jar and retain the artifact.
+ # For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
+
+ name: Build jar
+
+ on: [workflow_dispatch]
+
+ jobs:
+   build:
+     runs-on: ubuntu-latest
+     steps:
+     - uses: actions/checkout@v2
+     - name: Set up JDK 11
+       uses: actions/setup-java@v2
+       with:
+         java-version: '11'
+         distribution: 'adopt-hotspot'
+     - name: Grant execute permission for gradlew
+       run: chmod +x gradlew
+     - name: Build with Gradle
+       run: ./gradlew build -P toolchain=11
+     - uses: actions/upload-artifact@v2
+       with:
+         name: jar
+         path: build/libs
+         retention-days: 1