So ran into same issue. Seems even though Linux Mint java is a ..."1.8.???", that it's some IBM version of Java (that or I downloaded that version and installed by accident).
My answer was to uninstall (sudo apt-get remove) all versions I could find, and in some cases just delete the folders.
Problem #2 was I kept trying to make openjdk-11 work. But when I used the link Beelee provided (https://www.pcsteps.com/5492-how-to-install-java-linux-mint-ubuntu/), and copy pasted the commands into Terminal
sudo apt-get install openjdk-8-jre -y
sudo nano /etc/environment Then appending the file at the end on a new line
I was able to download maps. So I don't know enough about the CLI yet to tell if there is a problem with the Linux Mint default Java, but that is a possibility.
Mint has many 'quirks' for one reason or another, but it uses up much less memory than Ubuntu, hence can be popular on low power machines (Like my Toshiba CB-30; that couldn't run Ubuntu, but works well with Mint).