Iterable and Collection
Most of the core interfaces are rooted in Iterable and its Collection subinter-
face. Their generic types are Iterable<T> and Collection<E> .
Iterable describes any object that can return its contained objects in some se-
quence.Thisinterfacedeclaresan Iterator<T> iterator() methodthatreturns
an Iterator instance for iterating over all the contained objects.
Collection representsacollectionofobjectsthatareknownas elements .Thisin-
terfaceprovidesmethodsthatarecommontothe Collection subinterfacesonwhich
many collections are based. Table 5-1 describes these methods.