okay I can finally show off these things- Sun SPOTs, weird little java on metal microcontrollers from 2005/2006!

http://nug.only9fans.com/penny/SunSPOTs/

@penny it's not Java, but nowadays you can have crazy features on a microcontroller with an ESP32 and AtomVM, including Erlang Distribution so you can cluster together microcontrollers 😉