Travis CI couldn't install openjdk11

It seems to be an TLS certificate error of download.java.net. Current TLS certificate exposed by download.java.net is invalid: it's for download.oracle.com.

The 51 return code was returned by the curl download command.

You can download the install-jdk.sh script :

curl -o /tmp/install-jdk.sh -L https://raw.githubusercontent.com/sormuras/bach/master/install-jdk.sh

Then run it:

bash -x /tmp/install-jdk.sh --target "/home/travis/openjdk11" --workspace "/home/travis/.cache/install-jdk" --feature "11" --license "GPL" --cacerts

Failing command is:

curl -o /dev/null --silent --head --write-out '%{http_code}' https://download.java.net/java/GA/jdk11/9/GPL/openjdk-11.0.2_osx-x64_bin.tar.gz

with a 51 return code

To avoid this problem, try something like this in your .travis.yml configuration file:

language: java
dist: xenial
sudo: required

jdk:
  - openjdk11