Moved the failing call to ln into the guarded block via Don't link system CA certificates if target dir doesn't exist · sormuras/bach@c185fb8 · GitHub – version 2019-07-03 needs to be copied over to Travis CI. Again.
As stated here https://github.com/travis-ci/travis-build/pull/1347#issuecomment-385885801 and in various other places, the install-jdk.sh script was designed to just download and extract the latest-and-greatest JDK (from jdk.java.net) into a clean (CI) environment. Nothing more, nothing less.
I (still) don’t want to support more complex scenarios within the script. There are better solutions available, but I don’t know how if/whether Travis CI may make use of them: http(s) caching proxy techniques like http://www.squid-cache.org does is one option. The archived and released JDK URLs are very stable and should be pre-installed within Travis CI images, the EA releases change every 1-3 weeks. Supporting the latter was and is the main goal of install-jdk.sh.
Perhaps switching to a more complete Java Version Manager like GitHub - shyiko/jabba: (cross-platform) Java Version Manager is an option (for archived/released JDKs) for Travis CI.
Cheers,
Christian