This uses TeaVM to compile Java to JavaScript. Launches faster in browser than the desktop (once cached). Download is 1.2mb (compressed) - much smaller than desktop version. Runtime speed seems the same as desktop.
If we would travel back in time to the nineties and tell them we have technology that compiles Java to JavaScript they would put us straight to a psychiatric hospital :D
Do you have any insight or ideas on where the performance increases and size decreases are coming from?
Also, did you have to work a lot to get it working in TeaVM? The last I looked at it (which was admittedly over a year ago), it still required some non-trivial changes for the Java app I was working with at the time.
My app cross compiles to JVM and browser easily now, but I did a lot of work on the SnapKit UI framework, which is like Swing but abstracts out graphics and user input. My app used to be all Swing - that would be almost impossible with TeaVM. There is product called CheerpJ which does Swing with almost no modification, but it has a larger runtime.
This post links to the TeaVM version. TeaVM is also awesome - but it has a reduced runtime, conditional compilation and better built-in DOM support. The whole app + runtime is 1.2mb (compressed) and loads in seconds (instantly once cached).