I don't see what for me would be the key document: how is this technology addressing the plethora of reasons which made the applets fail.
Applets were executed completely outside of the browser sandbox. An absolute disaster from the security standpoint.
CheerpJ is effectively just a very sophisticated JavaScript/WebAssembly library and it plays by the rules of the browser sandbox.
> Applets were executed completely outside of the browser sandbox. An absolute disaster from the security standpoint.
It is easy to forget Java (applets, web start) was a thing during the Windows 98 era, meaning a time when there was (almost?) no security. People were downloading and running random .exe files all the time.
There was no browser sandboxing and you could run wild Basic code in IE.
Sun with Java were the first one to try to solve that problem. It was imperfect but way better than what others were doing at the time.
WASM has a better security sandbox. (Designed in from the beginning, not the thousand-fingers-in-the-dike retrofit that was the Java SecurityManager -- which was eventually deprecated and abandoned along with the Applet tech it was intended to support.)
I’d imagine the biggest one is that it doesn’t require the user to have installed a Java runtime on their computer.
Applets didn’t fail because of missing JRE, it was included in IE. It was only after Microsoft started playing around with the implementation that Sun asked them to stop, which they did. Only then did a missing JRE become an issue.