How to define JAVA_HOME
Determine and set JAVA_HOME to execute Java command-line applications.
Java
How to display Java settings
Use a dedicated option to display Java settings.
How to install OpenJDK 8 on Debian
Use AdoptOpenJDK/Eclipse Adoptium to install OpenJDK 8 (LTS)/OpenJDK 11 (LTS) or OpenJDK 15 (Latest) using Eclipse OpenJ9 or HotSpot Java virtual machine.