If Java is not recognized as internal or external command, you need to make sure that the installation is not problematic and its path is recognized as system variables.

Here are the three easiest ways to fix Java’s “not recognized as an internal or external command” error: Install or reinstall Java and the JDK on your computer Add Java’s bin directory to the computer ...

I’ll briefly make the case for migrating your code base to Java 11, then guide you through the steps to install Oracle JDK 11 using the Ubuntu command line.