The article literally links to a frontend that does just that, run the JVM on top of WASM. It performs fine: https://teavm.org/gallery.html

I'm not sure if I'd use it for a website or anything, but if my goal was to embed a simulation or complex widget, I wouldn't ignore it as an option.

It doesn't run the JVM. It's an ahead-of-time compiler that converts Java bytecode to wasm.

	▲	jeroenhd 3 days ago \| parent [-]
		Oh, if you want a full fat JVM, then you want CheerpJ https://cheerpjdemos.leaningtech.com/SwingDemo.html#demo Takes a few seconds longer to load because it loads all of Java Spring, but it still performs just fine on my phone (though the lack of on screen keyboard activation makes it rather unfortunate for use in modern web apps).