If not, install the latest version from adoptopenjdk.net.
This is the development environment and platform on which JJazzLab-X is built.
Netbeans IDE menu Team/Git/Clone
Enter repository address https://github.com/jjazzboss/JJazzLab-X.git
Leave user and password blank
Press Next and select the master branch (or another branch, if you know what you're doing)
Let Netbeans open the JJazzLab-X project from the cloned files
Select the JJazzLab-X project, right-click Build. When it's done you should see "BUILD SUCCESSFUL" in the Output window.
Select the JJazzLab-X project, right-click Run.
JJazzLab-X should start with the default language set up for your computer, e.g. if you use Windows in the German language, you should see JJazzLab in German. If a source phrase is not translated in the target language, the English one is used.
You can't switch the language from within the JJazzLab-X application when it is run from Netbeans IDE. But it's still possible to change language for test purposes:
In Netbeans, Projects tab, open the JJazzLab-X project, then the Important Files folder
Open Project Properties
Find "run.args.extra=..." and insert "--locale xx:XX " right after the "=" For example: "run.args.extra=--locale fr:FR \"
Use fr:FR for French, de:DE for German, en:US for English, it:IT for Italian, es:ES for Spanish, ja:JP for Japanese, zh:CN for Chinese (mandarin).