On: Myths Programmers Believe about CPU Caches (2018)

[jcranmer]

Okay, it looks like those were added in Java 9, which was after I stopped following Java (and well after the C++ memory model was largely settled, in 2007).

[re-thc → jcranmer]

Before Java 9 it could have been done using Unsafe. VarHandle just provides a slightly higher level construct.

[gpderetta → re-thc]

Was the behavior of more relaxed operations fully formalized in the way it fits with the rest of the memory model?

[hashmash → gpderetta]

Not with the Unsafe class. It was never intended to be used by anything except the built-in concurrency support classes, and it was just barely good enough. External libraries which made use of the Unsafe class did so by studying how it was used, and then assumed/concluded how it worked. Java 9 formalized everything with the VarHandle class, and it offers much more features than the Unsafe class.

[gpderetta → hashmash]

Thanks for the clarification. Java was obviously a trailblazer on formally introducing advanced memory models on practical languages, but it did take a few tries to get it correct.

[CyberDildonics → jcranmer]

Okay, it seems strange to make a sweeping generalization while assuming java had stagnated.