Select software version

Example: Choose Java 8 as default

sudo update-alternatives --config java

Enable PipeWire on Ubuntu 21.04

Sources: 1, 2

sudo apt install pipewire pipewire-audio-client-libraries libspa-0.2-bluetooth libspa-0.2-jack
sudo touch /etc/pipewire/media-session.d/with-pulseaudio
sudo cp /usr/share/doc/pipewire/examples/systemd/user/pipewire-pulse.* /etc/systemd/user/
systemctl --user daemon-reload
systemctl --user --now disable pulseaudio.service pulseaudio.socket
systemctl --user mask pulseaudio
systemctl --user --now enable pipewire pipewire-pulse
systemctl --user --now enable pipewire-media-session.service
reboot

To check which server is used:

pactl info