Write barrier for G1GC SATB wasn't atomic?

[Narihiro Nakamura]

> That's ok. The goal of SATB is to snapshot the object graph and track
> the changes to it. So, in your example, obj0 was the contents of the
> field before the snapshot. It doesn't matter if we capture it multiple
> times or values that were stored to the field after the snapshot - all
> of this will be filtered later. The important part is that we captured
> the value that was before the snapshot at least once.

Aha! I understand :)
Thank you very much for your detailed explanation and quick reply!!

-- 
Narihiro Nakamura (nari)
http://www.narihiro.info/index.en.html