[emehrkay]

Does everything that happens in the JVM happen on a single tread? I think that is the biggest bottleneck when you see slow performing web apps. I think that moving things off to web workers is the natural progression, but browser support...

[craigching]

Not everything, just UI work for AWT/Swing. Pretty much every UI framework that I've worked with over my 20 years of experience is single-threaded, uses an event-based queueing architecture. I'm sure others have a different experience though ;)

[jfim]

You're supposed to do all your graphics-related stuff in a single thread. Swing and JavaFX aren't thread-safe.