Trying to open minecraft in ubuntu

As I wrote here:

For some reason the desktop file for OpenJDK is not installed, even though this file is listed.

$ apt-file list openjdk-8-jre | grep desktop        
openjdk-8-jre: /usr/share/applications/openjdk-8-java.desktop
openjdk-8-jre: /usr/share/applications/openjdk-8-policytool.desktop

$ ls -l /usr/share/applications/openjdk-8-java.desktop
ls: cannot access /usr/share/applications/openjdk-8-java.desktop: No such file or directory

$ dpkg --get-selections | grep openjdk-8
openjdk-8-jre:amd64             install

Install Java with these commands, in order to get the required entry:

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

and then

sudo apt-get install oracle-java8-set-default

And in order to do things more easily, use the Minecraft Installer.

sudo add-apt-repository ppa:minecraft-installer-peeps/minecraft-installer
sudo apt-get update
sudo apt-get install minecraft-installer

Then run Minecraft from the Dash.