Memory barriers and coding style over a Java VM

Question

Suppose I have a static complex object that gets periodically updated by a pool of threads, and read more or less continually in a long-running thread. The object itself is

Answer 1

Having an immutable Foo with final a and b fields solves the visibility issues with the default values, but so does making theFoo volatile.

Personally I like having immutable value classes anyway as they much harder to misuse.