Minimwatch 2, Java and Gnome TopiconsPlus

[nickc]

I'm running Linux Manjaro Gnome release 20.0.3, Gnome v 3.36.4 and for some time the Minimwatch icons for my two instances of MinimServer (both on QNAPs) have not produced menus when clicked on. (They load on boot, are green, but inert.) They used to work fine, so I assume they lost functionality after a system upgrade of some kind. (I've tried replacing TopIconsPlus with TopIconsFix, but to no avail.)

I've now got round to upgrading to MinimServer 2, as that seemed a sensible first step. But I'm having uncertainty about installing Minimwatch 2 because I'm unsure of my Java setup. The terminal gives a result I don't fully understand:

Code:

[nick@nick-pc-3 ~]$ java -version
openjdk version "1.8.0_252"
OpenJDK Runtime Environment (build 1.8.0_252-b09)
OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)

When I look in 'Add/remove software' it tells me both OpenJDK Java 10 full and headless are installed (plus earlier versions too).

What I don't understand is how to a) check and b) remedy if necessary that the correct java version is available in the way Minimwatch 2 will need it. In other words, I think I need a little unpacking of this section of the Minimwatch 2 installation guide:

"After installing Java, use the command
java -version
to make sure Java is installed correctly and is available on the path. This is important for correct operation of the MinimWatch command scripts. "

I have done a quick search on the forum, but if the guidance/explanation I'm seeking is already out there and I've not found it, please forgive me and point me to a link.

Great to see the MinimServer eco system evolving like this, btw - congratulations!

[nickc]

Reflecting further, and re-reading Simon's instructions for installing Java, I'm wondering if the terminal result I posted refers to the Java in use with a Virtual Machine I have installed. But it doesn't seem to be version 10, which is definitely installed somewhere. Where can I find it? There isn't a Java folder in /usr/local/ and I'm loath to download another copy of Java and unpack to /usr/local/ in case I further muddy already troubled waters. I need a bit better grasp of what I'm trying to do.

[simoncn]

The correct way to to switch between multiple installed Java versions is to use the sudo update-alternatives command. There is a good explanation of this on this page. Note that the examples use "update-alternatives" but you will need to change this to "sudo update-alternatives".

It is not possible to get the icon displayed using Java 8. It you are using Java 9 or later, this should be possible.

[nickc]

Thanks for getting me on the right track, Simon.

It turns out that "update-alternatives" may be viable only on Debian and Ubuntu; I got a "command not found".

For the benefit of others, on Manjaro and ArchLinux, the command to use is "archlinux-java". So to find the current default version of java in use on the system it's: "archlinux-java status". Switching between versions (and much else) is covered very well here.

[simoncn]

Your "here" link is not working.

[nickc]

(28-07-2020 21:10)simoncn Wrote:  Your "here" link is not working.

Woops! Sorry about that - I think it does now.

[simoncn]

Yes, the link is working now. This page is extremely informative and comprehensive. Perhaps I should give Arch Linux a try. Is the icon working now?

[nickc]

(29-07-2020 07:48)simoncn Wrote:  Yes, the link is working now. This page is extremely informative and comprehensive. Perhaps I should give Arch Linux a try. Is the icon working now?

Yes it is, as is the one for the instance of Minimserver (not yet upgraded) running on my old TS-109. It seems as though it was at the point that MinimWatch required Java 9 or above on my Gnome desktop that the icons must have stopped working; I found the system default was Java 8 and as soon as I changed it to Java 10 they sprang back into life.

After moving from Ubuntu to Manjaro I've never really looked back.

[simoncn]

MinimServer 2 supports the TS-109 (this was an interesting challenge) so please take advantage and do the upgrade. The instructions are on this page.