Seems like JDK 13 is the default JDK on MacOS – install-jdk.sh is not invoked by Travis CI on that configuration. Compare the output to the other ones of MacOS:
11: https://travis-ci.org/forax/pro/jobs/628128983#L54 – 14 lines of installation log
12: https://travis-ci.org/forax/pro/jobs/628128984#L54 – 14 lines of installation log
13: https://travis-ci.org/forax/pro/jobs/628128985#L54 – empty
14: https://travis-ci.org/forax/pro/jobs/628128986#L54 – 14 lines of installation log
By not invoking install-jdk.sh, the JAVA_HOME environment variable is not set. It should point to:
/Library/Java/JavaVirtualMachines/openjdk-13.0.1.jdk/Contents/Home