Openjdk8 is not supported

[wangxiyuan]

When I tried using jdk: openjdk8
The log said that it only support version 9-14.

Then I use openjdk9, but the log said: Error: JAVA_HOME is not defined correctly.

[Michal]

Hi @wangxiyuan

Happy to see you testing ARM builds!

This is Early Release stage, so not all languages are pre-installed yet, including Java. It’s in queue, though.
Until the pre-installed version is delivered you can instruct your ARM build to install certain openjdk by properly adding commands in your .travis.yml in e.g. before_install: section or via

addons:
    apt:
      packages:
          # name the package

Please take a look at Installing Dependencies documentation for reference.

Hope it helps!