DiscoCLI

 Aloha,

As some of you might know I've created the so called DiscoAPI for foojay.io. This api should help you to get an OpenJDK distribution of your choice. In addition to the api itself I've also created different plugins for IDE's and browsers and also some tools like JDKMon.

That's all good stuff but I was always missing a command line tool which enables me to simply download an OpenJDK package of my choice in the terminal. Thank god there is Picocli which makes it possible to create a command line interface using Java.

If you use Picocli in combination with GraalVM's native image feature you can create a single binary which was exactly what I was looking for.

And even better...you can build the binaries for x64 based platforms easily using github actions.

Long story short, I've created the Disco Command Line Client or short DiscoCLI which makes it easy to download an OpenJDK distribution of your choice.

Here are some examples on how to use it:

Get Zulu with version 17.0.2 for the current operating system including JavaFX:

discocli -d zulu -v 17.0.2 -fx


Get the latest version of JDK 16 for Liberica on Windows:

discocli -d liberica -v 16 -os windows -latest

Get the JDK 17.0.2 of temurin for macos with aarch64 as a tar.gz and store it to a folder

discocli -d temurin -v 17.0.2 -os macos -arc aarch64 -at tar.gz -p /Users/hansolo


In case a JDK pkg cannot be found discocli will try to give you the available pkgs.

discocli -d liberica -v 12 -os linux -arc x64 -fx -latest

Sorry, defined pkg not found in Disco API

Packages available for Liberica for version 12:
discocli -d liberica -v 12.0.2 -os linux -lc glibc -arc amd64 -at tar.gz -pt jdk
discocli -d liberica -v 12.0.1 -os linux -lc glibc -arc amd64 -at tar.gz -pt jdk
discocli -d liberica -v 12 -os linux -lc glibc -arc amd64 -at tar.gz -pt jdk

It's also possible to simply check what packages are available for given set of parameters. If we would like

to know what packages are available of Zulu for Macos on aarch64 that come as tar.gz and offer a jdk for 

version 17.0.2, we could type the following:

discocli -f -d zulu -v 17.0.2 -os macos -arc aarch64 -pt jdk -at tar.gz

Packages found for Zulu for version 17:
discocli -d zulu -v 17.0.2 -os macos -lc libc -arc x64 -at tar.gz -pt jdk -fx
discocli -d zulu -v 17.0.2 -os macos -lc libc -arc x64 -at tar.gz -pt jdk

As always the code is available on github if you would like to build it yourself but if you simply would

like to download the binary, feel free to get it from the github releases.

I provide binaries for the following platforms:

- Macos x64 (but this also works on M1 chips because of Rosetta 2)

- Linux x64

- Linux aarch64

- Windows x64

For those of you that are asking themselves if this is not the same as SDKMan? No, it's not, SDKMan is much more

than this. DiscoCLI really only helps you downloading an OpenJDK distribution and that's it, no installation 

and nothing else than OpenJDK distributions. 

And in the near future DiscoCLI might also be available via SDKMan using JReleaser... :)

That's it for today...so keep coding... :)

Friday Fun LXIII - JDKMon

 Aloha,

I've took some days off this week and continued working on a little tool I wrote, JDKMon. Because I have a couple of JDK's on my machine and I usually don't use tools like sdkman or other installers but instead install the JDK's by hand I always wanted to have a tool that keeps track on the latest available versions and inform me about updates.

Well because I've created the Disco API for foojay I'm now able to use this api to create this tool. In principle the tool will try to find all JDK's installed in a folder (that you can define) and checks the Disco API for updates for each of the JDK's found. If an update was found it will tell you the latest available version for the distribution and give you the ability to download the different available versions.

Just to be clear, the tool won't scan your whole harddrive for installed JDK's but only the given folder with all it's subfolders. For me that works fine because I have all JDK's installed in the same folder. 

On MacOS this folder usually can be found at /Library/Java/JavaVirtualMachines where on Windows it can be C:\Program Files\Java and on Linux it might be /usr/lib/jvm. But like mentioned you can choose the folder JDKMon should look for JDK's.

JDKMon will scan for new updates every 3 hours and will show you a notification if there are updates available. The app makes use of FXTrayIcon which makes it possible to have the app running in the SystemTray (if available). On MacOS and Windows that works fine. On Linux it won't work so in this case it is simply an app that comes with a menu.

After the app started it will scan for JDK's and will then show a window with all JDK's found. On MacOS that window will like look like follows:

On the screenshot above you see the alphabetical list of JDK's found in the folder that is shown on top. The distributions where the tool found updates will have additional info like the arrow followed by the latest available version and some colored buttons. The buttons on the right will show the available archive types for each distribution. Once you click on one button it will ask you for a folder to download the package to and after you have selected one it will download the selected package to that folder.

So the tool won't install automatically the downloaded JDK...this is up to you. The tool will also adopt to the selected screen mode (dark/bright) on MacOS and Windows. I've also tried to make the main window and notifications look like the native windows. Here is a screenshot of the Windows version on a bright themed Windows 10 installation:

The supported distributions at the moment are:

- Adoptium (but there are no packages yet)

- AdoptOpenJDK HotSpot

- AdoptOpenJDK OpenJ9

- Corretto

- Dragonwell

- GraalVM CE

- Liberica

- Liberica Native

- Mandrel

- Microsoft Build of OpenJDK*

- OJDK Build

- Oracle JDK (no direct download)

- Oracle OpenJDK

- RedHat (no direct download)

- SAP Machine

- Trava

- Zulu

* The Microsoft Build of OpenJDK is currently not available on the public Disco API but only on my own server which is the reason why you can see it on the Windows screenshot. But it will come with the next deployment.

Like already mentioned this is just a tool that I needed for my own machine and I also used it to test the detection of dark/light mode etc.

Because the Disco API still is under development it might come to situation where you don't find the latest available JDK of a distribution directly but I'm working on that so that it will hopefully be up to date most of the times.

As always the source code is available over at github where you can also find the installers/jars in the releases section.

I'm using github actions to build and upload the artifacts with each build so that you can also find the latest available artifacts for MacOS and Windows in the actions section.

The tool is not finished yet because it needs a bit more love for Linux which will be the next task to do. At least it should look not like a MacOS app on Linux forever. So I will try to adjust it to maybe the Ubuntu UI.

That's it for today, so enjoy the upcoming weekend and...keep coding... 

"Poor man's" dark mode detection

 Aloha,

I recently read a lot about how to detect the dark mode on MacOS or Windows from Java which is really interesting when you develop desktop applications in Java (yes they still exists).

And there are different ways in figuring this out, one of them is to use jSystemThemeDetector which not only detects the theme but also gives you the ability to listen to changes of the theme. This little library makes use of different other libraries like OSHI, JFA, Jetbrains Annotations and JNA. 

Because I also wrote a little tool that helps me to figure out the system color theme I thought I might share this with you.

So my approach is a bit different in the way that I simply make use of the already existing operating systems tools to get the information I need. If you don't need to listen to theme switches (which is usually the case because users do not change their theme all the time) but only need to know if the operating system is currently using the dark theme or the light theme then you might want to use my approach.

I simply call operating system routines on the command line using Java's Runtime.getRuntime().exec() method and parse the result.

Because I'm on MacOS I've also added the ability to get the current accent color that is used in MacOS which is useful if your application should be as close to the native MacOS apps as possible.

Because the JavaFX stage does not recognize the current MacOS theme means you have to draw the window frame on your own dependent on the current theme but that's fine. I might add another blogpost about the native looking MacOS windows frame I've created.

The thing that I like most about my little tool is that it is only one class that offers some utility methods and everything is plain Java without any dependencies. 

It works on MacOS and Windows 10 and for those of you that are interested in that tool, I've created a little gist.

At the moment this utility class is made for JavaFX but it should be easy to change the Color definitions from JavaFX to Java Swing if you need them :)

That's it for today, enjoy your weekend and keep coding... :)