Raspberry Pi’s come with Java pre-installed. If you are using less than version 11, it is recommended you run a distribution upgrade on your Pi.
sudo apt update sudo apt dist-upgrade sudo apt clean sudo reboot
The following will install the pi4j library that Java will use to interface with your Raspberry Pi hardware controls such as the GPIO.
curl -ssl https://pi4j.com/install | sudo bash
If you have any issues with the above command, check the detailed installation instructions for pi4j
wget -o - https://packagecloud.io/headmelted/codebuilds/gpgkey| sudo apt-key add - sudo apt-get install code-oss=1.29.0-1539702286 apt-mark hold code-oss
Instructions sourced from makeuseof