Hi Neil,
Endless OS 3.0 took a bold shift with regard to how applications are distributed/installed and it now relies on flatpak, which is well-known and secure way to distribute applications in Linux, regardless of the specific environment you’re running (e.g. you could install the same app in Fedora, Endless, Debian…).
For that reason, the Java JRE that you could run directly in Endless 2.6.x has been moved into Endless’s flatpak runtime, so that apps installed via the app store can still use Java, which is the only officially supported way to run Java on Endless at the moment.
Unfortunately, this means you can no longer run java programs directly from the system (e.g. from the terminal), since the JRE is no longer accessible there. However, if you want to take a workaround, you could always install Oracle’s Java Runtime into /opt and then you’d have java available again in your system, but this is not supported in any way by Endless, so you’d be on your own there. If you still want to do it, these would be the steps, roughly:
- Download Sun’s JRE by selecting the “Linux x64” tarball from http://java.com/en/download/linux_manual.jsp
- Install (uncompress) the JRE somewhere under /opt (e.g. /opt/jre1.8.0_91)
- Set up PATH and other environment variables you might need (e.g. CLASSPATH) to run your java thing
- Probably something else I might be forgetting
Hope this helps!
Mario