Clojure is a hosted language, so we need to install a Java run-time environment (JRE). Java is typically installed on all modern operating systems.
Open a terminal and run the following command (you will be prompted for your login password to complete the install)
sudo apt-get install openjdk-8-jre
openjdk-8 not available or not the right version?
If openjdk-8 is not available, add the WebUpd8 Java personal package archive
sudo add-apt-repository ppa:webupd8team/java sudo apt-get update
Switching between Java versions If you have more than one version of Java installed, set the version by opening a terminal and using the following command
sudo update-alternatives --config java
Available java versions will be listed. Enter the list number for the version you wish to use.
Using Homebrew, run the following command in a terminal to install Java 11:
brew cask install adoptopenjdk11
If that command does not work, use this instead to install the latest version.
brew tap AdoptOpenJDK/openjdk
Switching between Java versions
You can run more than one version of Java on MacOS. Set the Java version by opening a terminal and using one of the following commands
Show the Java versions installed
Switch to Java version 1.8
export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)
Change back to Java version 11
export JAVA_HOME=$(/usr/libexec/java_home -v 11)
Chocolatey is a package manager for Windows (similar to Homebrew for MacOSX)
Install the Java Runtime (JRE) using the following commands in a command window
choco install javaruntime
Run the file once downloaded and follow the install instructions.
Check Java is working
Open a terminal and run the command
If Java is installed, you will see something like this in your terminal:
The details of Java's version may differ from what you see above; that is perfectly fine, so long as you have Java version 8 or above.