Using a MacOS, you are trying to run a command (e.g., a "java" command) from the Terminal utility (character prompt). You get the message "No Java runtime present", and the command fails. What should you do?
Using the GUI, download the .dmg file from here.
Once it is downloaded, double click it. Follow the menu steps (Continue -> Install -> (enter a password if/when prompted), -> Close). Make sure it is installed. Now you should not see that problem again.
To browse Mac products, see this link.