install gradle:
https://linuxhint.com/installing_gradle_ubuntu/

wget -c https://services.gradle.org/distributions/gradle-7.5.1-bin.zip -P /tmp
sudo unzip -d /opt/gradle /tmp/gradle-7.5.1-bin.zip

create sample application with gradle:
https://docs.gradle.org/current/samples/sample_building_java_applications.html

install jdk18 if not in apt
https://askubuntu.com/questions/1421306/how-to-install-openjdk-18
* wget the tar
* unpack to /opt
* set the bin folder in the JAVA_HOME ev