If you just count the JS and HTML, then a minimal Electron app is (hopefully) also tiny.

That's not the same though. You have to bundle electron to run your app. Your Java app is fine as long as Java is installed.

Yes, but theoretically Electron apps could use the browser. (I think Google killed that option though.)

Yeah, it would be nice if the API's were standardized and then every browser had an "App Mode".

I should have been more explicit; this is the default in memory footprint of a simple hello world app. I didn't really try to reduce the heap or stack of the JVM, I'm sure that would help.

Oh I think this is a misunderstanding. I thought you were talking about the binary file size which is very big for electron apps since they ship a full-blown browser. It is possible that JavaFX apps also use a lot of memory (RAM) but I was referring to the file size of the .jar file of a JavaFX app.