The Minecraft.deb has the default-jre dependency. On Ubuntu 20.04 this is openjdk-11-jre.
There are two (admittedly hacky) solutions I came up with to fix this:
• Edit the Minecraft.deb file by unpacking the 'control' file and replacing the "default-jre" dependency by "openjdk-8-jre". Then put the .deb package back together.
• Download the Minecraft.tar.gz archive from the website (Other distributions button). Unpack it into your desired location (default for the deb is /opt/minecraft-launcher). Create a symlink in /usr/bin and/or a .desktop file in /usr/share/applications. Make sure just openjdk-8-jre is installed.
There are probably better solutions out there, but those are the ones I came up with. The update-alternatives command could probably work too and would be way simpler, but I didn't try yet.
The Minecraft.deb has the default-jre dependency. On Ubuntu 20.04 this is openjdk-11-jre.
There are two (admittedly hacky) solutions I came up with to fix this:
• Edit the Minecraft.deb file by unpacking the 'control' file and replacing the "default-jre" dependency by "openjdk-8-jre". Then put the .deb package back together.
• Download the Minecraft.tar.gz archive from the website (Other distributions button). Unpack it into your desired location (default for the deb is /opt/minecraft-launcher). Create a symlink in /usr/bin and/or a .desktop file in /usr/share/applications. Make sure just openjdk-8-jre is installed.
There are probably better solutions out there, but those are the ones I came up with. The update-alternatives command could probably work too and would be way simpler, but I didn't try yet.