Is Java installed on Linux Mint?

You can set the default Java version on your system according to your specific requirements. That is all about the installation of Java in Linux Mint 20.

Does Linux come with Java?

There are many Linux distributions available and many of them come with one or more Java platform/s pre-installed. In the vast majority of the cases the Java platform which comes pre-installed on a Linux machine is not the official Oracle Java, but another one such as OpenJKD or IBM Java.