Fun fact: The original, original demo (pre-acquisition) was Lua based. Andy was skeptical that enough people would know what Lua was so I shifted it over to Javascript. So for a while we were Javascript + 2d render engine. Smells a bit like WebOS or Flutter (though much less fancy in that early sketch).
Shifting from Lua to JS is not trivial! What JS engine did you use?
And can you tell us a bit more about the choice of Java to create apps? Wasn't it frustrating for all the C++ coders in your team to use such a "slow" language for apps?
At the time (very very early) there was only a small amount of code and small amount of native bindings, so it only took a couple days to rebuild the lower layers and I recall Chris got the "framework" running again in js pretty quickly after that was done. I think maybe we used spidermonkey? It's been 15+ years... somebody at Google with access to the fadden demo should be able to figure it out quickly enough.
As for Java, it worked well enough for Hiptop at Danger on a 24MHz ARM7TDMI platform. We felt we could use a similar approach (use Java more for "business logic" and do the heavy lifting in native libraries and services) to get sufficient performance on the 200MHz+ ARM9 platforms we were looking at, and take advantage of having a real MMU for process protection and eventually supporting native code (the latter, more contentious).
Everyone basically did Lua back in that era since it was so damn small. I had it running on 400kb of memory on the PSP, used it for multiple UI frameworks around that era on mobile hardware.
Someone still hasn't built an equivalent to LuaJIT. Quickjs is in the same spirit but still interpreted, the way LuaJIT does C FFI is just pure awesome[1].
