Install Leiningen using SDKMAN

First install SDKMAN

If you use Ubuntu maybe you will need to install the curl package: sudo apt install curl
Open new terminal and enter: curl -s "https://get.sdkman.io" | bash
always after from the terminal: source "$HOME/.sdkman/bin/sdkman-init.sh" or open new terminal
Check if it has been installed correctly: sdk version

Now install Java

To install the latest stable version of Java: sdk install java
To verify that Java has been correctly installed: java -version

Install Leiningen

Now you can finally install Leiningen with the command: sdk install leiningen
lein version to check if it has been installed