Value integrity guarantee for concurrent long writes in 64-bit OpenJDK 7/8

Question

Note: this question isn\'t related to volatile, AtomicLong, or any perceived deficiency in the described use case.

The property I am trying to prove or rule out is as f

Answer 1

In fact, you've already answered your own question.

There is no "non-atomic treatment" of double and long on 64-bit HotSpot JVM, because

1. HotSpot uses 64-bit registers to store 64-bit values (x86_64.ad vs. x86_32.ad).
2. HotSpot aligns 64-bit fields on 64-bit boundary (universe.inline.hpp)