Last I heard you still had to call out into JavaScript, manipulating the same old DOM to get anything done.

Maybe someone could set up a library that implements Swing on top of a HTML Canvas? Just waiting for all the classes to download would help with that nostalgic feeling.

Already done.

https://leaningtech.com/cheerpj/

https://teavm.org/

The cheerpj implementation of swing seems to work quite well. Just some lag when it loads resources not quite asynchronously and hard crashing sometimes when I switch the look and feel to Motif. Better than I expected.