E- The type of value in the fast collection.
@Deprecated public interface FastIterable<E> extends Iterable<E>
A fast iterable is an iterable that may support fast iteration — iteration where the same object is returned each time, having been mutated to represent the next state. It can save greatly in object allocation overhead in some circumstances. Using a fast iterator is only possible if the looping code doesn't allow objects returned by the iterator to escape the loop (e.g. it doesn't save them away in other objects or something), but many loops only observe the object and then discard it before the next iteration. Those loops benefit from fast iterators.
@Deprecated Iterator<E> fastIterator()