[pjmlp]

> Does java detect that this escaped the stack? How?

There isn't one Java, rather lots of it.

So, in what concerns Oracle, there are reports from Oracle Labs that Graal is better than Hotspot on escape analysis.

No idea where IBM, Azul, Aicas, microEJ, PTC stand.

Even less regarding Android, because not only Google has done their own thing, each OEM also has the freedom to change how ART works.

Regarding your actual question, I have this feeling none of them is able to detect it.