Unfortunately the javapackager tool will be removed with JDK 11 - as it is part of JavaFX, which will also be removed. Hence, there will be no "official" and easy way to create native Java application bundles for Mac or Windows any longer.
I tried to re-use the native launcher files generated by Java 9/10's javapackager (on Mac: my.app/Contents/MacOS/my) and they still seem to work with JDK 11. However that's a bit of a dirty solution. Any ideas about how to natively package and launch applications with Java 11 and beyond (Mac platform preferred)?
As ccpizza commented above:
As of JDK14 you can now use jpackage as shown here: stackoverflow.com/a/66511673/191246 (still incubating though) – ccpizza