Atomically updates (with memory effects as specified by VarHandle.compareAndSet) the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.

Parameters:

obj		An object whose field to get and set
x		the update value
accumulatorFunction		a side-effect-free function of two arguments

Returns:  the previous value

Since:  1.8