Github action: setup-java with multiple JDKs and corresponding environment variables

Question

Background: I've a spring-boot 2.3 project using reactive driver for cassandra that is built on Java 11. For integration test though, when I spin up an embedded Cassandra database, I rely on presence of Java 8 on the machine with accompanying environment variable JAVA8_HOME.

Question: How can I configure GitHub action setup-java to utilise multiple JDKs for my build and let JAVA_HOME point to Java 11 but JAVA8_HOME point to Java8?

Answer 1

Using multiple JDKs with GitHub actions is already possible today. One great and neat way is to leverage the strategy.matrix job configuration like that in your .github/workflows/maven.yml:

name: github

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        java-version: [ 8, 11, 15 ]

    steps:
    - uses: actions/checkout@v2
    - uses: actions/setup-java@v1
      with:
        java-version: ${{ matrix.java-version }}
    - run: mvn -B install --no-transfer-progress --file pom.xml

I didn't check if this does include the environment variable configuration for JAVA_HOME you need - but it clearly isolates the build environments for the separate Java versions. Here's a full example project using this setup: https://github.com/codecentric/cxf-spring-boot-starter and here's a green build log.

Also the GitHub actions GUI for matrix builds is quite nice: