Look up DoD (DoW?) 882 and LOR ratings. This is a fancy way of saying “Java can’t do that because we haven’t certified a toolchain for it”

And for bonus points, go find the last certified compilers for LOR1 rating that follow 882 guidelines.

Now you’ve scratched the surface of safety-critical software. Actually writing it is a blast. I think most web developers would weep in frustration. “Wait, I can’t allocate memory that way? Or that way? Or in this way not at all?! There’s no framework?! You mean I need to do all this to verify a button click??!!”

Most web developers don't know what "memory allocation" is and let alone how to manually allocate it.

I think people that don't write safety-critical software in general will weep in frustration, not just web developers.