Java 16 install (manual) on Ubuntu or Linux w/Azul

 This article was a lifesaver for me when trying to upgrade the Java version for my kid's Minecraft server.  Seems the latest Minecraft Server 1.17.1, requires Java 16 which requires a little finagling on my Ubuntu VM.

All credit goes to https://docs.azul.com/core/zulu-openjdk/install/debian

Install from Azul APT repository

You can add Azul’s APT repository to the list of package sources on your system and install Azul Zulu by using your OS package manager.

Note	The Azul’s repository contains DEB packages for the x86 architectures. If the CPU architecture of your machine is different from x86 (for example, arm64 or arm32), consider installing the appropriate TAR.GZ package. You can find TAR.GZ packages for all supported platforms on the Downloads page.

Installing with a package manager requires root privileges. Log in as root or use sudo when running the commands listed below.

1. Set up the Azul APT repository:

    # install the necessary dependencies
   sudo apt-get -q update
   sudo apt-get -yq install gnupg curl 
   
   # add Azul's public key
   sudo apt-key adv \
     --keyserver hkp://keyserver.ubuntu.com:80 \
     --recv-keys 0xB1998361219BD9C9
   
   # download and install the package that adds 
   # the Azul APT repository to the list of sources 
   sudo curl -O https://cdn.azul.com/zulu/bin/zulu-repo_1.0.0-2_all.deb
   
   # install the package
   sudo apt-get install ./zulu-repo_1.0.0-2_all.deb
   
   # update the package sources
   sudo apt-get update 

2. When the repository is set up, install the required Azul Zulu package by running apt-get install <package>. For example, to install Azul Zulu JDK 11, run:

    # install Azul Zulu JDK 11
   sudo apt-get install zulu11-jdk 

   See the Azul Zulu Packages section below for information about available packages.

3. To verify your installation, run the java -version command. You should see output similar to the following:

    $ java -version
   openjdk version "11.0.10" 2021-01-19 LTS
   OpenJDK Runtime Environment Zulu11.45+27-CA (build 11.0.10+9-LTS)
   OpenJDK 64-Bit Server VM Zulu11.45+27-CA (build 11.0.10+9-LTS, mixed mode)