Why is this not working???

Question

https://code.sololearn.com/c5aBK236096e/?ref=app

Answer 1

ooh Applet, you need a browser to run an applet. since in SL the program run in SL server so its imposible here.
and if you want to develop in desktop, you'll need an older browser. newer version of major browser already remove applet support

Answer 2

this chrome add on, compile java applets to js, (I didn't try it)
https://chrome.google.com/webstore/detail/cheerpj-applet-runner/bbmolahhldcbngedljfadjlognfaaein