Install groovy package on focal
Solution 1:
This package can be installed on Ubuntu 20.04 LTS system by simple download from 20.10 repository using commands below:
cd ~/Downloads
wget -c http://archive.ubuntu.com/ubuntu/pool/universe/k/knxd/knxd_0.14.35-1_amd64.deb
sudo apt-get install ./knxd_0.14.35-1_amd64.deb
You are very lucky here, all dependencies will be satisfied automatically.