For the overflow, Jagex with RuneScape did it in Java. They also did stupid Object arrays 7 or so levels deep, doing casts on casts in between. The bytecode its

For the overflow, Jagex with RuneScape did it in Java. They also did stupid Object arrays 7 or so levels deep, doing casts on casts in between. The bytecode itself made the actual runtime slow to a crawl (anywhere from 5 to 10x slowdown.) This was circa 2014.