List子介面的實現類:ArrayList/Vector/LinkedList

List集合：元素有序。可重複的集合，List集合預設按元素的新增順序設定元素的索引，通過索引來訪問物件

List集合原始碼？

public interface List<E> extends Collection<E> {
//定義了Collection集合的通用方法

int size();
boolean isEmpty();
Iterator<E> iterator();
Object[] toArray();
boolean add(E e);
boolean containsAll(Collection<?> c);
boolean addAll(Collection<? extends E> c);
boolean addAll(int index, Collection<? extends E> c);
boolean removeAll(Collection<?> c);
boolean retainAll(Collection<?> c);
@since 1.8從jdk8開始介面支援有方法體，必須為static/default修飾
default void replaceAll(UnaryOperator<E> operator) {
    Objects.requireNonNull(operator);
    final ListIterator<E> li = this.listIterator();
    while (li.hasNext()) {
        li.set(operator.apply(li.next()));
    }
}
default void sort(Comparator<? super E> c) {
    Object[] a = this.toArray();
    Arrays.sort(a, (Comparator) c);
    ListIterator<E> i = this.listIterator();
    for (Object e : a) {
        i.next();
        i.set((E) e);
    }
}
void clear();
boolean equals(Object o);
int hashCode();
//定義List集合介面專有的方法

E get(int index);
E set(int index, E element);
void add(int index, E element);
E remove(int index);
int indexOf(Object o);
int lastIndexOf(Object o);
ListIterator<E> listIterator();
ListIterator<E> listIterator(int index);
List<E> subList(int fromIndex, int toIndex);
}