Installing Openhabian on Ubuntu 20.04.1 - Which Java to install?

I have been running Pi3 Openhabian for about 6 months now. Regulars here would have seen my pleas for help at times.
I inherited an Intel NUC so I decided I would install Openhabian on it. I’ve followed the installation documentation but it says very little on the Java install.
openhabian-config shows Zulu 8 32 & 64 bit, Zulu 11 32 & 64 bit and AdoptOpenJDK 11 but the docs give no indication which is preferred. As they are all available I guess they all work.
Can someone suggest the best option?

there is a recommendation in the prerequisites https://www.openhab.org/docs/installation/#prerequisites which describes the requirements.

This is the problem with the documentation. I’m installing Openhabian so I would expect everything pertaining to the installation of Openhabian to be there but no it is in the Openhab installation docs.
The Openhab documentation above states;
" Make sure that you have an up to date Java 8 platform installed on your host system."
but openhabian-config offers versions 8 & 11 for installation. Is the documentation out of date and now Openhab supports Java 11 or should I stick with Java 8?

openHABian was not designed to run on Ubuntu, so don’t expect it to run properly or being well documented for your use case…

The Documentation is not out of date, openHAB 2.5.x still requires Java 8 whereas openHAB 3.0 will require Java 11 (and only Java 11, not 12/13/14 or whatever will be available)

Now I’m even more confused. The Openhabian documentation states clearly;

Other Linux Systems (add openHABian just like any other software)

openHABian is also supposed to run on generic Debian based systems on x86 and some ARM hardware platforms. Start with a fresh installation of your operating system, login and run etc.

Isn’t Ubuntu a Debian based Linux?

And why does the openhabian-config for Openhabian 2.5 offer Java 8 & 11 for installation?

There is no openHABian 2.5, it’s version is 1.6
If you search the community, you will find a longer thread where poeple tested openHAB 2.x with Java 11.
Some tests had been positive, some failed. So this is why the option for Java 11 was added.

Openhabian is a bunch of scripts to install openHAB and other features.

Which of those other features are you using?

I’ve run openHAB on Ubuntu using the install instructions from the openHAB documentation, and it all went smoothly. If you don’t need the extra features that come bundled with the openhabian scripts, you may be better off manually installing. All the extra features can usually be installed separately anyway.

And for openHAB 2.5, use Java 8.

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My mistake, openhabian 1.6, it’s openhab that is 2.5. As I said at the beginning I’ve been using OpenHAB2 on a Pi3 by using the Openhabian image that is why I went down the openhabian path for my Linux install.
From openhabian-config I’ve installed the latest openhab, mosquitto, samba and now I’ve got to install Java. My initial question was what version of Java to install and that has been answered. I still don’t understand why openhabian-config 1.6 for openhab 2.5 offers menu options to install Java 8 or 11 if Java 11 doesn’t work with openhab 2.5.

Most functionality already works with Java 11. openHABian has the Java 11 option so users can help testing how well it works (you’ve got to start somewhere to iron out bugs).

If you want something that just works go for Java 8 unless you already know you want to use some Java 11 functionality in your rules. You can always change your Java version later on if you decide to do so.

As for the 32/64-bit option, go for the option your OS allows for. That will probably be 64-bit on a NUC.

No this is the problem with people being too hasty and careless.
It’s all there - if you look in the right place, the openHABian README.

openHAB consists of various sub projects from various contributors (e.g. bindings), each to contribute their own documentation. Assembling all of that into a single ‘monolithic’ docs structure and style isn’t easy.

But a README is the first thing one should read when downloading a new software package, isn’t it ?

I’ve added (another) prominent link from the official docs over there (it takes some time to get replicated).

You’ve just highlighted the problem. Why would I have gone there?
The Openhabian documents are here (https://www.openhab.org/docs/installation/openhabian.html) with no link to the readme page, however, the readme refers to this documentation for installation details.
I can’t see anything about the Java version needed in the readme.
How is a beginner to know that not all documentation is in the one place?

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The proper place for user documentation is the OH website. If you want it elsewhere set the website documentation to be a redirect.

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Thanks Bruce, that is exactly where I went for installation information when I decided to do a Linux installation.
I think openhabian is a good route for someone with little Linux experience to get Openhab up and running. Not as easy as the image for Raspberry Pi but that’s to be expected.

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@lesterb Although as a lazy Unix admin I agree with you the openHABian developers want to concentrate on the Raspberry Pi.