How to install Zulu java from azulsystems as an alternative to OpenJDK.
OpenJDK is sometimes slightly behind the official Oracle releases as well as that OpenJDK doesn't provide all the Java versions for all OS'es. (For instance Java 12 isn't available from repo on Ubuntu 16 but only on Ubuntu 18)

Simplest way to install is via repository. Procedure described here is for Ubuntu but for other flavors of Linux the procedures are here: https://docs.azul.com/zulu/zuludocs/ZuluUserGuide/PrepareZuluPlatform/AttachAzulPackageRepositories.htm

Adding the repo

Import Public Key

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0xB1998361219BD9C9

Add the actual repository

apt-add-repository 'deb http://repos.azulsystems.com/ubuntu stable main'

Update the cache for all packages

apt-get update

or

apt update

Installing

Actual installation of packages

apt install zulu-{version number}

or

apt-get install zulu-{version number}