类继承关系

• Iterable
  • Iterator<T> iterator()
• Collection<E> extends Iterable<E>
  • int size()
  • boolean isEmpty()
  • boolean contains(Object o)
  • Iterator<E> iterator()
  • Object[] toArray()
  • T[] toArray(T[] a)
  • boolean add(E e)
  • boolean remove(Object o)
  • boolean containsAll(Collection<?> c)
  • boolean addAll(Collection<? extends E> c)
  • boolean removeAll(Collection<?> c)
  • boolean retainAll(Collection<?> c)
  • void clear()
  • boolean equals(Object o)
  • int hashCode()