[roblabla]

Basically, just recompile for the M1. For the rare apps that have some assembly or cpu-specific intrinsics (e.g. for vectorization in math-heavy code), you'll need to port those to ARM64 as well, but that should be very rare.

[jsheard]

Atomics can be a pain point as well. The strong memory model of x86 tolerates sloppy use of atomics so bugs can easily fly under the radar, until the code is re-compiled for a weaker memory model like ARMs and suddenly you have a nightmare web of race conditions to deal with.

[Tuna-Fish]

IDEA contains a JRE which has a JIT compiler. This is of course entirely cpu-specific, so had to be completely redone. OFC, ARM JITs for java already existed so they just had to ship to one of those.