public abstract boolean weakCompareAndSet (T obj, long expect, long update)

Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value. This method is guaranteed to be atomic with respect to other calls to compareAndSet and set, but not necessarily with respect to other changes in the field.

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.

obj    An object whose field to conditionally set
expect    the expected value
update    the new value

Returns:  true if successful