Ref: https://travis-ci.org/walterhiggins/ScriptCraft/builds/641863564
Build error is:

Expected feature release number in range of 9 to 15, but got: 8

Ref:
https://changelog.travis-ci.com/xenial-as-the-default-build-environment-99476

Xenial as the default build environment (9 months ago)
As announced two weeks ago, we've started incrementally updating the default build environment to Ubuntu Xenial 16.04.
Right now, 5% of the repositories building that do not explicitly specify an Operating System, os: key, or an Ubuntu Linux distribution, via the dist: key are now being routed to Ubuntu Xenial 16.04 instead of Ubuntu Trusty 14.04.
We'll continue increasing the percentage of repositories using the new default throughout the next few weeks and posting updates here as we move forward.
To test how Xenial will work for you, please specify it directly with
dist: xenial.
Make sure to bring any questions you might have to the Travis CI Community Forum: Xenial.
If you'd like to stay on Trusty, that's also an option, you can pin your repository to continue using Ubuntu Trusty 14.04, by specifing dist: trusty in your .travis.yml file.

As directed by the Travis CI team, I'm going to change the .travis.yml file, first to use Xenial, and if that doesn't work, I'll bump the JDK to v9.

Ref build https://travis-ci.org/walterhiggins/ScriptCraft/builds/641867679
This one completed successfully after .travis.yml was set to use OpenJDK9.
When building ScriptCraft we can still use v8, this change was only made for the Travis CI.
Though we should always use the latest stable JDK and JRE.

Leaving open for @walterhiggins to view and close.