Is this a thread-safe problem?

[Forrest Wang]

Hi wusheng:
        Is there a thread-safe problem about the following field? Is it 
necessary to make all of the elements of this array volatile?
        For example, when thread A set buffer[1] to null, but the old value of 
buffer[1] is in the cache of cpu which Thread B is running on. Then the save 
action will fail if strategy is IF_POSSIBLE.
B.R.