Instructions on how to install and manage Java in Ubuntu 20

install-java.md

Java Installation and Management in Ubuntu 20

Installation

sudo apt-get install openjdk-8-jdk

# don't worry, you can apt-get multiple java versions
sudo apt-get install openjdk-11-jdk
#sudo apt-get install openjdk-...  <tab complete to see all available versions>

Management

# list available javas
update-java-alternatives --list  # you should see 8 and 11 if you followed my instructions from above
sudo update-java-alternatives --set /path/to/java/version  # you will get the right path from the previous step

# make sure to have this line in your .bashrc or .zshrc
# export JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:bin/javac::")