They are talking about his https://en.wikipedia.org/wiki/Java_applet

Which were absolutely everywhere at the turn of century.

So, yeah...if you are only thinking about web applets, which died over 20 years ago, and ignoring Android, which runs on most of the world's phones, I see why you might think "Java is dead."

Thanks to WebAssembly it is back.

http://teavm.org/

The web client specifically